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The Phaeton Chassis Design and Function

Self-Study Program Course Number 893303

Volkswagen of America, Inc. Service Training Printed in U.S.A. Printed 08/2003 Course Number 893303 ©2003 Volkswagen of America, Inc. All rights reserved. All information contained in this manual is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of Volkswagen of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, nor may these materials be modified or reposted to other sites without the prior expressed written permission of the publisher. All requests for permission to copy and redistribute information should be referred to Volkswagen of America, Inc. Always check Technical Bulletins and the Volkswagen Worldwide Repair Information System for information that may supersede any information included in this booklet. Trademarks: All brand names and product names used in this manual are trade names, service marks, trademarks, or registered trademarks; and are the property of their respective owners.

Table of Contents

Introduction ............................................................................... 1 The Chassis Front Axle .................................................................................. 4 Front Axle Rear Axle .................................................................................. 10 Rear Axle for Front-Wheel Drive, Rear Axle for 4Motion Alignment ................................................................................ 14 Measurement Guidelines Steering .................................................................................... 16 Steering System Overview, Steering Column, Servotronic II Variable Effort Power Steering Brakes ....................................................................................... 30 Brake System Overview, Wheel Brakes, Foot Parking Brake, Brake Lines and Cables, Pedal Cluster, Bosch 5.7 Antilock Brake System Wheels and Tires ..................................................................... 46 Tire Pressure Monitoring Knowledge Assessment ......................................................... 57 New!

Important/Note! The Self-Study Program provides you with information regarding designs and functions. The Self-Study Program is not a Repair Manual. For maintenance and repair work, always refer to the current technical literature.

i

Introduction In top form, the Phaeton chassis fulfills even the most challenging demands on comfort and driving dynamics. The Phaeton makes important contributions to active vehicle safety through several of its chassis components, including: • Speed-dependent power-assisted steering. • Four-link front suspension. • Trapezoidal wishbone rear suspension. • Electronic Stabilization Program (ESP) with Brake Assist.

SSP277/033

1

Introduction The Chassis Major chassis components and features on the new Phaeton include: • Four-link front suspension with 64.09-inch (1628 mm) track width • Trapezoidal wishbone rear suspension with 63.46-inch (1612 mm) track width • Front and rear anti-roll bars • Independent wheel suspension front and rear • Air suspension with continuously controlled damping • Foot-actuated parking brake • Brake Assist • Speed-dependent power-assisted steering • Ventilated disc brakes • Tire pressure monitor • Electronic Stabilization Program (ESP)

2

Introduction

SSP277/002

3

Front Axle Front Axle The Phaeton front axle is equipped with four-link suspension. The multitude of guide elements produces the following advantages:

• Good driving comfort. • Exceptional anti-squat and anti-dive performance.

• Isolation from unwanted drive forces from the steering. • High steering precision through optimized positioning of the pivot axis.

SSP277/129

4

Front Axle Component Overview

Bearing Block (Cast Aluminum)

Front and Rear Upper Suspension Links (Forged Aluminum)

Wheel Bearing Housing (Cast Steel)

Subframe (Hydroformed Steel)

Guide Link (Forged Aluminum) Anti-Roll Bar (Steel)

Bearing Link (Forged Steel) SSP277/010

5

Front Axle Bolted Wheel Bearings Wheel Hub

Wheel Bearing Housing Bolted Connection

Wheel Bearing

The wheel bearings are not pressed into the wheel bearing housings. They are bolted to the wheel bearing housing. This enables the wheel bearing to be installed without removing the pivot bearing or jointed shaft.

Bolted Connection

SSP277/044

Anti-Roll Bar

Rubber Bushing with Aluminum Pipe Clamps

Depending on the engine, the Phaeton has either a solid anti-roll bar 1.38 inches (35 mm) in diameter or a tubular anti-roll bar 1.38 inches (35 mm) in diameter with a wall thickness of 0.24 inch (6 mm). The rubber bushings and aluminum pipe clamps are vulcanized onto the anti-roll bar in this design and cannot be replaced. This support arrangement was designed to have radially rigid and rotationally flexible characteristics.

SSP277/025

6

Front Axle Subframe The subframe is made of high-pressure hydroformed tubular steel. It is bolted to the body using rubber-metal bushings. This flexible connection keeps the body free of forces and impacts that the chassis introduces. The additional bolted brace ensures ample transverse rigidity.

Brace SSP277/026

Air Spring Strut to Suspension Link Connection The air spring strut is attached to the bearing link with a rubber-metal bushing.

Air Spring Strut

Bearing Link

SSP277/037

7

Front Axle Virtual Steering Axis

The steering axis thus formed by the line through these two points of intersection is in free space. This is why it is referred to as a virtual steering axis.

With the Phaeton four-link front suspension, the steering axis does not run through the upper and lower joints on the wheel bearing housing as with conventional front axle designs.

It does not change position at full steering lock.

On the Phaeton front axle, the steering axis runs through two intersection points that are derived by extending the lines formed by the two axes of the connections between the two upper suspension link joints, and similarly derived from the connections between the two lower suspension link joints.

This arrangement enables the steering axis to be placed close to the wheel center plane. This has a positive effect on the scrub radius which improves handling.

1-4

Directions of the Suspension Links R Wheel Center Point A Wheel Contact Point n Trail nv Castor Offset p Scrub Radius a Road Feedback Lever Arm Point AS = Piercing Point of the Steering Axis on the Road Surface

2

1

4

R

3

nv a

AS

A n

p SSP277/029

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Front Axle Full Steering Lock Positions This axle design allows the virtual steering axes to be shifted much further outboard than would otherwise be possible.

Link Position for Left Turn

The position of the steering axis determines the castor angle and the steering swivel inclination. By optimizing the axle geometry, it is possible to reduce the effects of torque steer. Since the wheels are located using four ball sockets on the ends of the transverse links, the pivot axis can run approximately through the vertical center of each wheel, regardless of physical space requirements.

SSP277/070

Link Position for Straight Driving

The wheel moves around the virtual steering axis. The virtual steering axis changes position as the steering mechanism moves the wheels from lock to lock. The defined movement of the virtual steering axis during steering reduces the space requirements in comparison to conventional axle systems with fixed-space steering axes. SSP277/040

Link Position for Right Turn

SSP277/072

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Rear Axle Rear Axle for Front-Wheel Drive (Not Available in the North American Market) In the Phaeton, the rear axle is designed with unequal length trapezoidal wishbone suspension. All wheel location elements are mounted to a rigid subframe that resists torsion and warping.

The subframe is connected to the body using large dimension rubber bushings. This configuration achieves exact wheel location and good ride quality.

Wheel Bearing Housing

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Wheel Hub

Bolted Connection

Rear Wheel Hub Stub Axle

Bolted Connection

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Instead of the bolted constant velocity joint pivot, the wheel bearing is pre-stressed with a stub axle. The rear axle for front wheel drive vehicles is similar to the axle for all-wheel drive vehicles, but the rear axle drive and jointed shafts are not used.

Rear Axle Rear Axle for 4Motion All Phaetons sold in the North American market have 4Motion all-wheel-drive systems. The subframe holds the rear differential at three points.

Between the isolation provided at these three mounting points, and the isolation provided by the subframe mounts, the rear differential is doubly isolated from the body.

SSP277/016

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Rear Axle Integrating a coupler into the hub carrier connection and using a track rod has optimized the toe-in behavior of the rear axle.

The passive steering properties and noise insulation provided by the Phaeton rear axle design have improved upon designs used in previous vehicles.

Steel Subframe

Forged Aluminum Transverse Link

Rubber-Metal Bushing

Cast Aluminum Axle Link

SSP277/068

Bolted Joint for Camber Correction

Bolted Joint for Track Correction

Wheel Bearing Housing

Coupler

Track Rod SSP277/018

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Rear Axle Rubber Bushings

Anti-Roll Bar An solid anti-roll bar 0.79 inch (20 mm) in diameter is installed on the rear axle. The rubber bushings are vulcanized onto the rear axle anti-roll bar as they are on the front axle anti-roll bar. SSP277/031

Wheel Bearing Housing As with the front axle wheel bearings, the rear axle wheel bearings are bolted to the wheel bearing housings. The wheel bearings on the front and rear axles are identical in construction. Wheel Bearing Housing

Wheel Hub

Bolted Connection

Bolted Connection

SSP277/044

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Alignment Measurement Guidelines Before every alignment measurement, the level position of each suspension strut must be checked. The familiar parameters of camber and toe-in must be measured and adjusted as necessary on the rear or front axle during alignment procedures.

Toe-In Curve Diagram -4.72 (-120)

In addition, toe-in must be checked and set as necessary at the front axle when the suspension is extended. This adjustment must be made with the wheels raised 2.36 inches (60 mm) when the vehicle is empty. Adjusting the toe-in curve with the wheels in an extended state sets the toe-in curve for driving stability.

Extension in Inches (mm)

-3.94 (-100)

60

-3.15

(-80)

-2.36

(-60)

-1.57

(-40)

-0.79

(-20)

40

20

-20

-40

-60

Toe-In in Degrees

14

0.79

(20)

1.57

(40)

2.36

(60)

3.15

(80)

3.94

(100)

Compression in Inches (mm)

SSP277/042

Alignment Front-End Alignment The following steps are important when performing the front-end alignment:

For complete front-end alignment instructions, refer to the Repair Manual.

• Setting the basic toe-in with an empty vehicle by changing the length of the track rod. • Setting the inclination of the toe-in curve by changing the height of the outer track rod joint.

Adjustment Range for the Toe-In Curve

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Adjustment Option for Independent Toe-In

SSP277/020

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Steering Steering System Overview

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Steering Column The Phaeton is equipped with an adjustable steering column. The adjustment range is 1.97 inches (50 mm) in the axial direction and 1.57 inches (40 mm) in the vertical direction.

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Steering Electric Steering Column Adjustment The electric steering column is steplessly adjustable in the axial and vertical directions. The adjustments are driven by two electric motors: • Motor for Steering Column Adjustment, Vertical V123 • Motor for Steering Column Adjustment, Axial V124 Pull Tab Console

Motor for Steering Column Adjustment, Axial V124

Crash Carriage

Motor for Steering Column Adjustment, Vertical V123 SSP277/081

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Steering Electric Steering Column Adjustment Functional Diagram The convenience CAN data bus carries the command signal to adjust the steering column, and the Driver’s Seat/Mirror Position Control Module J543 processes it. The Steering Column Electronic Systems Control Module J527 interprets and reads the driver’s input from the Steering Column Adjustment Switch E167 and places the signal on the convenience CAN data bus.

The Driver’s Seat/Mirror Position Control Module J543 then sets the Motor for Steering Column Adjustment, Vertical V123 and the Motor for Steering Column Adjustment, Axial V124 to the corresponding positions. Hall-effect sensors in the Motor for Steering Column Adjustment, Vertical V123 and the Motor for Steering Column Adjustment, Axial V124 send the return signals to the Driver’s Seat/Mirror Position Control Module J543.

Steering Column Adjustment Switch E167 ± Axial, ± Vertical

Control Unit for Steering Column Electronics J527 Motor for Steering Column Adjustment, Axial V124

Steering Column Axial Position Sensor

Control Unit for Driver Seat/Mirror Position J543

Steering Column Vertical Position Sensor

Motor for Steering Column Adjustment, Vertical V123

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Steering Electric Steering Column Lock The Phaeton uses an electric steering column lock instead of a mechanical steering lock. The electric steering column lock is an integrated system with an electrical interface to the Access/Start Control Module J518 and a mechanical interface to the steering column.

When the electric motor of the Steering Column Lock Actuator N360 is activated, the worm gear moves the push rod in the longitudinal direction. To lock the steering column (terminal 15, off), the locking collar with internal teeth is pushed over the conical locking star with external teeth until it stops. To unlock the steering column (terminal S, on), the locking collar is pulled away from the locking star.

Locking Collar

Unlock Push Rod

Locking Star

Lock

M

Worm Gear

Steering Column Lock Actuator N360 Control Module with Two Hall Sensors

Access/Start Control Module J518

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Steering Servotronic II Variable Effort Power Steering The Phaeton is equipped with Servotronic II variable effort power steering. This hydraulic steering system, which is electronically controlled and speed dependent, is

distinguished by light, comfortable steering during parking and other low-speed maneuvers, and a precise driving feel as speed increases.

Power Steering Pump V119

Servotronic Solenoid Valve N119

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Steering Servotronic Characteristic Curve Diagram

The Servotronic variable effort power steering system is based on hydraulic steering. The hydraulic steering modified rotary valve uses the principle of direct hydraulic reaction (feedback).

The diagram shows how the pressure changes with respect to steering wheel movement in relation to driving speed. The characteristic curve has been specifically adjusted to the vehicle character.

Using an electro-hydraulic converter and steering valve enables the Servotronic system to change the amount of steering assist according to driving speed.

Pressure psi (kPa) 1,740 (12,000) 0 mph (0 km/h) 1,450 (10,000) 31 mph (50 km/h) 1,160

(8,000) 75 mph (120 km/h)

870

(6,000)

580

(4,000)

290

(2,000)

0 7.38 (10)

5.90 (8)

4.43 (6)

2.95 (4)

1.48 (2)

0

1.48 (2)

2.95 (4)

Steering Wheel Movement – lbs-ft (Nm)

4.43 (6)

5.90 (8)

7.38 (10)

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Steering Electric Control The Servotronic Control Module J236 evaluates the road speed signal from the Instrument Cluster Combination Processor J218 and converts the signal into modulated current. This actuates the Servotronic Solenoid Valve N119. The Servotronic Solenoid Valve N119 determines the hydraulic reaction at the rotary valve and thus the application moment at the steering wheel.

The speed-dependent influence on the steering translates into minimum forces required for steering effort at standstill and low speeds. Since the hydraulic reaction changes in relation to driving speed, the application force at the steering wheel increases with increasing speed. This gives the driver especially good road feel and precise steering control.

Servotronic Control Module J236

Instrument Cluster Combination Processor J218 Road Speed Signal

15

31

Servotronic Solenoid Valve N119 SSP277/095

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Steering Safety with the Servotronic System The steering system remains functional if the vehicle electrical system fails or other electrical faults occur. The Servotronic system then works using the mechanical forced opening of the Servotronic Solenoid Valve N119 at maximum hydraulic reaction.

If the road speed signal fails while driving, the Servotronic system remains at the last given control range until the ignition is turned off. The next time the engine is started, the maximum hydraulic reaction develops.

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Steering The Servotronic System in Operation The rotary valve in neutral position – vehicle stationary Power Steering Pump V119 generates the hydraulic pressure that the Servotronic system requires, about 1,885 psi (13,000 kPa), which is transferred to the rotary valve.

Rotary Valve

Control Bushing

Torsion Bar

In the valve unit, a torsion bar is pinned to the rotary valve on one side and to the driving pinion and control bushing on the other side. The torsion bar is responsible for centering (neutral position).

Servotronic Control Module J236

Road Speed Signal

Return Reservoir From Pump Torsion Bar Servotronic Solenoid Valve N119 To Left Working Cylinder

To Right Working Cylinder

Reaction Piston

Pin Connection Rotary Valve

Power Steering Pump V119

Pressure and Flow Relief Valve

Left Working Cylinder

Right Working Cylinder

Control Bushing

SSP277/053

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Steering The oil that the Power Steering Pump V119 supplies flows through the connection hole in the valve region and into the inflow radial channel. It then flows into the cross holes in the control bushing to the inflow control channels in the rotary valve. In the valve neutral position, the oil flows via the open inflow control vanes into all axial channels in the control bushing. From there it also flows via the open return control vanes into the return control channels in the rotary valve.

From these channels, the oil can flow through connections into the return chamber, and from there back to the oil reservoir. At the same time, the radial channels in the valve body and the associated tube lines connect the right and left working cylinder chambers.

Return Control Vane Return Control Channel Return Control Vane Inflow Radial Channel Inflow Control Vane Inflow Control Channel

Inflow Control Vane Axial Channel SSP277/055

Radial Channel Inflow Radial Channel Reaction Piston Radial Channel

Reaction Chamber

Return Chamber

Right Working Cylinder

From Pump

Left Working Cylinder Control Bushing

Return SSP277/057

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Steering Rotary valve in working position, left full steering lock – driving at low speed At left full steering lock, oil must flow to the right side of the working cylinder to assist the steering effort. The force at the steering wheel turns the torsion bar in its elastic range, since it is pinned to the rotary valve at the top and to the control bushing and driving pinion at the bottom. The torsion bar, which narrows in the appropriate region, turns the rotary valve against the control bushing.

Control Bushing

Rotary Valve

The pressurized oil travels via the inflow control vanes, which are further open, into the associated axial channels, through the hole in the radial channel and via a tube line to the right cylinder chamber, thus hydraulically assisting the steering rack to move. The pressurized oil in the right cylinder chamber pushes the oil out of the left cylinder chamber into the return line. If the driver releases the steering wheel, the torsion bar ensures that the rotary valve and the control bushing spring back into the neutral position.

Servotronic Control Module J236

Torsion Bar

Road Speed Signal

Return

Reservoir

From Pump Servotronic Solenoid Valve N119 From Left Working Cylinder

To Right Working Cylinder

Reaction Piston

Torsion Bar Pin Connection Rotary Valve

Power Steering Pump V119

Pressure and Flow Relief Valve

Left Working Cylinder

26

Right Working Cylinder

Control Bushing SSP277/059

Steering The Servotronic Control Module J236 evaluates the road speed signal and passes it on to the Servotronic Solenoid Valve N119 as modulated control current.

A baffle ensures that the return pressure level also acts in the reaction chamber. Thus, the Servotronic rotary valve behaves as a normal rotary valve in this situation.

Due to the maximum current produced in this driving situation, the Servotronic Solenoid Valve N119 closes and prevents oil from flowing from the inflow radial channel to the reaction chamber.

The steering is light and can be operated with little effort since the reaction has been eliminated.

Baffle Radial Channel Inflow Radial Channel

Servotronic Solenoid Valve N119

Reaction Piston Reaction Chamber

Radial Channel Return Chamber To Right Working Cylinder From Left Working Cylinder

From Pump

Return

Control Bushing

SSP277/061

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Steering Rotary valve in working position, right full steering lock – driving at high speed At right full steering lock, oil must flow to the left side of the working cylinder to assist the steering effort. The force at the steering wheel turns the torsion bar in its elastic range, since it is pinned to the rotary valve at the top and to the control bushing and driving pinion at the bottom. The torsion bar, which narrows in the appropriate region, turns the rotary valve against the control bushing.

Control Bushing

Rotary Valve

Torsion Bar

The pressurized oil travels via the inflow control vanes, which are further open, into the associated axial channels, through the hole in the radial channel and via a tube line to the left cylinder chamber, thus hydraulically assisting the steering rack to move. The pressurized oil in the left cylinder chamber pushes the oil out of the right cylinder chamber into the return line. If the driver releases the steering wheel, the torsion bar ensures that the rotary valve and the control bushing spring back into the neutral position.

Servotronic Control Module J236

Road Speed Signal

Return Reservoir

Torsion Bar

From Pump Reaction Piston Servotronic Solenoid Valve N119 To Left Working Cylinder

Pin Connection Rotary Valve

Power Steering Pump V119

From Right Working Cylinder

Pressure and Flow Relief Valve

Left Working Cylinder

28

Right Working Cylinder

Control Bushing SSP277/063

Steering As the speed increases, the Servotronic Control Module J236 reduces the control current to the Servotronic Solenoid Valve N119. With this, the Servotronic Solenoid Valve N119 takes on a certain opening position and enables a limited oil inflow from the inflow radial channel into the reaction chamber. A baffle prevents large amounts of oil from flowing out into the return chamber, so that higher pressure develops in the reaction chamber. The increased pressure acting on the reaction piston then generates a greater pressing force on the balls guided by V-ways. These balls are located between the reaction piston and the centering piece, which is firmly joined to the control bushing. During straight driving, this has a positive effect on the centering of the rotary valve, making it particularly exact. When the rotary valve pivots, the balls, which are now more highly loaded, exert additional resistance against turning of the rotary valve. Therefore, with the hydraulic reaction

Baffle Inflow Radial Channel Servotronic Solenoid Valve N119

in this sequence of operations, the specifically determined application moment required to move the steering wheel is higher. At high driving speeds, the Servotronic Solenoid Valve N119 is completely open due to the very low or zero control current. Thus, the inflow radial channel supplies maximum pressure to the reaction system. When the driver turns the steering wheel to the right, the reaction pressure also increases corresponding to the prevailing operating pressure and pushes the reaction piston out of the reaction chamber. As soon as the reaction pressure, which is determined specifically for the vehicle, is reached, the cut-off valve opens and the oil flows out into the return chamber so that the pressure does not increase further. The application moment at the steering wheel now does not increase further, and conveys a secure driving feel through optimum contact with the roadway.

Ball Reaction Piston Reaction Chamber Centering Piece

Cut-Off Valve

Return Chamber

Control Bushing SSP277/065

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Brakes Brake System Overview The Bosch 5.7 Antilock Brake System (ABS) with integrated Electronic Stabilization Program (ESP) and hydraulic Brake Assist is standard equipment on all Phaeton models. It is a diagonally separated two-circuit system. This high-performance brake system includes newly developed front and rear wheel brakes with large ventilated brake discs.

Pedal Cluster Dual Brake Booster

ABS Hydraulic Unit N55 Front Wheel Brake

30

Brakes

Rear Wheel Brake

Brake Cables Brake Lines Foot Parking Brake

SSP277/006

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Brakes Wheel Brakes To satisfy demanding safety requirements and guarantee a high level of comfort, the wheel brakes have been specially designed for the Phaeton. Brake Disc Sizes The Phaeton is equipped with different size brake discs depending upon which engine is used on the vehicle. Front Wheel Brakes A new aluminum brake caliper was developed for the Phaeton front wheel brakes. This lightweight brake caliper consists of a monoblock housing design that does not separate. It has eight pistons and four brake pads. This arrangement ensures optimum conditions for pressing the brake pads onto the brake disc. The brake caliper design has a wide reach around the friction ring. It achieves low mass combined with optimal caliper stiffness. SSP277/103

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Brakes Front Brake Discs The front brake discs are constructed from two parts. A friction ring is attached to a brake disc cup with sliders.

Aluminum Brake Disc Cup

This design allows the brake discs to freely expand in the radial direction. This significantly improves the thermal shock resistance, increasing the service life of the brake disc. At the same time, this type of connection has a favorable effect on the deformation of the friction ring under temperature loading. This reduces noise during brake application. A positive result of this design is the weight saved by manufacturing the brake disc cup from aluminum. The specially formed cooling ribs provide a robust construction with optimal flow-through. Specially shaped rims and an air guide move the air stream directly to the brake disc.

Friction Ring Slider

SSP277/012

Rear Wheel Brakes The Phaeton rear wheel brakes are high-performance, ventilated disc brakes. They use newly developed aluminum brake calipers. The parking brake feature is integrated into the rear brake calipers.

SSP277/008

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Brakes Foot Parking Brake The Phaeton uses a foot-actuated parking brake. It is distinguished by its low weight, minimum release force, and responsive design. The main components of the parking brake pedal assembly are manufactured from aluminum alloy. The parking brake is located in the left side of the footwell above the footrest. The parking brake is applied by pressing the pedal.

When the driver presses the foot parking brake pedal, a control cable transfers the applied force to a lever mechanism under the floor of the vehicle. Here, the force is divided over two brake cables, which operate the actuating mechanisms on the rear wheel brakes. The parking brake is released by pulling the release lever by hand. Release Cable

Release Lever

Pedal

Control Cable SSP277/109

34

Brakes Coil Spring

Foot Parking Brake Coil Spring The coil spring, which acts on a drum, takes on the brake locking function. The spring slides on the drum and expands due to the direction of movement.

Cable Retainer

Drum

Plastic Spring

If the counter force of the brake moves the spring in the other direction, it pulls together and increases the friction between the coil spring and drum. Thus, the pedal locking action is almost completely stepless and noiseless. An additional plastic spring produces the typical click sound when the pedal is pressed.

Control Cable Pedal SSP277/156a

Release Cable Coil Spring

When the driver pulls the release lever, the retainer of the release cable is drawn upward. This expands the coil spring, or in other words, the spring becomes moveable and the pedal can return to the initial position. This principle requires low release forces.

Drum

Retainer for Release Cable

SSP277/156b

Lock The coil spring tightens around the drum when the pedal moves in the opposing direction. SSP277/152

Release The diameter of the coil spring becomes larger when the spring expands. The coil spring can move on the drum.

SSP277/154

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Brakes Actuation of the Rear Wheel Parking Brakes When the driver applies the foot parking brake, the brake cables actuate the parking brake lever on the brake caliper. The actuating shaft turns and performs a stroke.

The mounting of the actuating shaft on three balls, which are positioned on a sloped disc, produces the stroke. The stroke movement actuates the piston which clamps the brake caliper and presses the brake pads against the brake disc.

Parking Brake Cable

Parking Brake Lever

SSP277/008

36

Brakes Automatic resetting The increase in clearance that results from brake pad wear must be compensated for by the caliper.

A turning action of the resetting nut on the threads of the push bar resets the clearance to compensate for the increase in clearance that results from brake pad wear.

Push Bar

Sloped Disc Parking Brake Lever

Actuating Shaft Brake Pad Housing Brake Disc Compression Spring

Resetting Nut

Caliper Piston Spring Washer

SSP277/108

37

Brakes

When the driver applies the service brakes and hydraulic pressure develops in the brake system and brake calipers, the piston moves in the housing toward the brake disc.

Push Bar

The resetting nut is carried in the piston by a spring washer. If the clearance increases due to brake pad wear, it is compensated in the threads between the push bar and resetting nut. Resetting Nut Increased Clearance

SSP277/110

The force of the compression spring on the resetting nut acts against the pressing direction of the piston. This opens the cone clutch between the resetting nut and the piston.

Push Bar

Resetting Nut Cone Clutch

SSP277/112

38

Brakes

The push bar is held by the compression spring. The turns of the threads between the push bar and resetting nut are engaged in this resetting sequence. The coarse-pitch threads between the push bar and resetting nut produces a turning moment on the resetting nut. The cone clutch between the resetting nut and the piston opens far enough so that the resetting nut can turn on the threads of the push bar by the amount of the increased clearance in the brake application direction.

Push Bar

Resetting Nut

This resetting process takes places also when the brake caliper is relieved, that is, after the braking process.

Nominal Clearance

SSP277/114

Thus the brake wear that occurs while braking is directly and non-incrementally reset. The nominal clearance is the play between the resetting nut and push bar threads determined by tolerances.

When the pressure on the brake caliper is relieved, a clearance between the brake pads and brake disc appears.

Push Bar

Resetting Nut Clearance

SSP277/116

39

Brakes Brake Lines and Cables Hydraulic Brake Lines The brake lines are galvanized steel pipes that have a corrosion-resistant surface protection provided by the zinc plating and an additional polyamide coating. These lines are attached to the body with plastic holders. A robust, hard outer shell is used for attachment. Soft injected elements are used for noise insulation. The flexible connections in the lines to the front and rear axles are brake tubes. The inner tube consists of a material that prevents water absorption into the brake fluid. For stability, this tube has several braided fiber sleeves, which are protected against external influences by rubber.

The lines the engine compartment as well as the connection lines between the ABS Hydraulic Unit N55 and the brake booster are connected to plastic tubes with braided steel sheathing. The structure of these lines also reduces noise transfer from the ABS Hydraulic Unit N55 during operation. Foot Parking Brake Cables The foot parking brake cables are sheathed in polyamide and greased to prevent corrosion and reduce friction forces.

Structure of the Parking Brake Cable

Profile Wire Spiral

Polyamide Coating

Protective Shell (Polyurethane) Lining Tube (Polyamide) Steel Cable

SSP277/102

40

Brakes Pedal Cluster The bearing block of the pedal cluster is made of aluminum alloy. It is designed to break at a specific location in the event of a crash. This reduces the likelihood of injury to the driver’s lower legs and feet.

Custom covers are installed on the pedals for appearance purposes.

SSP277/117

41

Brakes Bosch 5.7 Antilock Brake System The Phaeton uses the Bosch 5.7 Antilock Brake System (ABS) with Electronic Stabilization Program (ESP) and hydraulic Brake Assist.

SSP277/131

42

Brakes Bosch 5.7 ABS Features • The hydraulic unit and control unit are integrated into a single ABS Hydraulic Unit N55.

• An ESP feature without preloading is provided. • The ESP has EDL, TCS, and ABS features as well as Brake Assist.

• The brake pressure sensing Sender 1 for Brake Booster G201 screws directly into the ABS Hydraulic Unit N55. ABS Hydraulic Unit N55

Sender 1 for Brake Booster G201

SSP277/106

SSP277/104

43

Brakes Active Wheel Speed Sensors The Bosch 5.7 ABS uses four active ABS wheel speed sensors:

ABS Wheel Speed Sensor

• Right Rear ABS Wheel Speed Sensor G44 • Right Front ABS Wheel Speed Sensor G45 • Left Rear ABS Wheel Speed Sensor G46 • Left Front ABS Wheel Speed Sensor G47 SSP277/160

Sensor Housing

Each ABS wheel speed sensor is made of a material that changes its electrical conductivity depending on a magnetic field. An electronic switch converts the current fluctuations induced in the sensor material into voltage fluctuations at the sensor output.

Sensor Electronics

Signal Wheel SSP277/158

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If the signal wheel moves relative to the sensor, the sensor generates a square-wave voltage signal at the corresponding frequency depending on the speed of rotation. The advantage compared to previously used systems is that it is possible to exactly detect the speed of wheel rotation right down to zero rotation.

Brakes Tandem Master Cylinder with Brake Booster The tandem master cylinder has a stroke of 1.42 inches (36 mm). The diameter of the main brake cylinder is 1.063 inches (26.99 mm). The tandem master cylinder with brake booster has light-weight construction and the following additional features:

Vehicles with ACC have active brake boosters. For more detailed information, please refer to The Phaeton Adaptive Cruise Control, Self-Study Program Course Number 898303.

• The central valves of the tandem master cylinder guarantee the shortest application distance at the pedal combined with reliable, self-priming ESP functionality. • The active (electrically activated) brake booster variant use in brake systems on vehicles that have Adaptive Cruise Control (ACC) represents the core component for activation with automatic delay of the vehicle in ACC operation and helps ensure regulated, automatic delay.

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Brake Booster Membrane Position Sensor G420 (Only in Vehicles with ACC)

Connection for Release Switch (Only in Vehicles with ACC)

Magnetic Coil for Brake Pressure in Brake Booster N247 (Only in Vehicles with ACC)

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Wheels and Tires Tire Pressure Monitoring System Overview

Function Selector Switch II E272

Antenna for Tire Pressure Check, Front Right R60 Sensor for Tire Pressure Front Right G223

Instrument Cluster Combination Processor J218

Antenna for Tire Pressure Check, Rear Right R62

Sensor for Tire Pressure Front Left G222

Antenna for Tire Pressure Check, Front Left R59 Sensor for Tire Pressure Rear Right G225

Antenna for Tire Pressure Check, Rear Left R61 Sensor for Tire Pressure Rear Left G224

Tire Pressure Monitoring Control Module J502

Sensor for Tire Pressure Spare Tire G226

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Wheels and Tires Tire Pressure Monitoring System Function The tire pressure monitoring system continuously monitors the tire pressure while driving and when the vehicle is stationary. The tire pressure monitoring system used in the Phaeton is a five-wheel system. The spare wheel is also monitored and included in the system messages. A measuring and transmitting unit mounted in each tire valve sends radio signals at regular intervals to the antennas mounted in each wheel housing. The signals are then passed on to the Tire Pressure Monitoring Control Module J502.

The Tire Pressure Monitoring Control Module J502 evaluates the tire pressures or changes in tire pressure and sends corresponding system messages to the Instrument Cluster Combination Processor J218. The system messages then appear on the Display Unit in Instrument Cluster Y24. If the driver has selected the “Vehicle” menu in the Front Information Display Control Head J523, the system messages for tire pressure monitor are displayed. The system recognizes the following situations: • Gradual pressure loss: The system informs the driver in time to be able to correct the tire pressure. • Sudden pressure loss: The system warns the driver immediately while driving. • Excessive pressure loss when the vehicle is stationary: The system warns the driver immediately after the ignition is turned on.

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Wheels and Tires Sensors for Tire Pressure The tire pressure monitoring system on the Phaeton uses five sensors for tire pressure: • Sensor for Tire Pressure Front Left G222 • Sensor for Tire Pressure Front Right G223 • Sensor for Tire Pressure Rear Left G224 • Sensor for Tire Pressure Rear Right G225 • Sensor for Tire Pressure Spare Tire G226 The sensors for tire pressure are screwed to the metal valves and can be reused when the wheels or rims are changed. The following components are integrated into each sensor for tire pressure: • Transmitter antenna • Pressure sensor

The pressure sensor detects the actual tire inflation pressure (absolute pressure measurement). The pressure is then sent to the Tire Pressure Monitoring Control Module J502 for evaluation. The temperature signal is used for compensating temperature-dependent pressure changes in the tires as well as for diagnostic purposes. The Tire Pressure Monitoring Control Module J502 performs the temperature compensation. The measured tire inflation pressures are normalized to a temperature of 68°F (20°C). The pressure sensor, temperature sensor and measuring and control electronics are integrated into one intelligent sensor. When the driver selects “Store pressures,” the tire inflation pressures are again normalized to 68°F (20°C).

• Temperature sensor • Measuring and control electronics • Battery

To avoid inaccurate settings, special care must be taken to ensure that the tire pressures are checked, corrected, and stored when the tires are cold.

Transmitter Antenna Pressure Sensor Sensor for Tire Pressure

Temperature Sensor

Metal Valve

Measuring and Control Electronics

Battery SSP277/358

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Wheels and Tires Antennas for Tire Pressure Check The tire pressure monitoring system on the Phaeton uses four antennas for tire pressure check:

Antenna for Tire Pressure Check

• Antenna for Tire Pressure Check, Front Left R59

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• Antenna for Tire Pressure Check, Front Right R60 • Antenna for Tire Pressure Check, Rear Left R61 • Antenna for Tire Pressure Check, Rear Right R62 The following information is sent to the antennas for tire pressure check from the transmitter antennas of the sensors for tire pressure: Sensor for Tire Pressure

• Individual identification number (ID code). • Current tire inflation pressure (absolute pressure). • Current tire air temperature. • Condition of the integrated battery. • The status, synchronization, and control information necessary for secure data transfer.

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ID codes

0000597200

Each sensor for tire pressure has an individual identification number (ID code), which is used for “own wheel recognition.”

0000755100 0000578100 0000602300 0000598100

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Wheels and Tires Function The antennas for tire pressure check receive radio signals from the sensors for tire pressure and transfer these signals to the Tire Pressure Monitoring Control Module J502 for further processing. The four antennas for tire pressure check used on the Phaeton tire pressure monitoring system are mounted in the wheel housings behind the wheel arch shells. They are connected to the Tire Pressure Monitoring Control Module J502 using high frequency antenna lines and are allocated according to their location.

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The antennas for tire pressure check receive all radio signals transmitted in their reception and frequency range. Each antenna for tire pressure check receives the radio signals of all wheel sensors that are in range. The Tire Pressure Monitoring Control Module J502 filters and selects the radio signals so that it can process the correct information. The spare wheel does not have a separate antenna for tire pressure check assigned to it.

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The antennas for tire pressure check receive the radio signals that the Sensor for Tire Pressure Spare Tire G226 transmits (data messages) and transfer the signals to the Tire Pressure Monitoring Control Module J502. The Tire Pressure Monitoring Control Module J502 recognizes and stores the “fifth wheel” as the spare wheel using own wheel and position recognition.

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Wheels and Tires Tire Pressure Monitoring Functional Diagram G222

G223

R59

G224

R60

G225

G226

R61

R62 15

+

S

J502

J218

J523 SSP277/124

Components

Color Codes

G222 G223 G224 G225 G226

Sensor for Tire Pressure Front Left Sensor for Tire Pressure Front Right Sensor for Tire Pressure Rear Left Sensor for Tire Pressure Rear Right Sensor for Tire Pressure Spare Tire

Input Signal

J218 J502 J523

Instrument Cluster Combination Processor Tire Pressure Monitoring Control Module Front Information Display Control Head

Convenience CAN Data Bus

R59

Antenna for Tire Pressure Check, Front Left Antenna for Tire Pressure Check, Front Right Antenna for Tire Pressure Check, Rear Left Antenna for Tire Pressure Check, Rear Right

R60 R61 R62

Output Signal Positive Ground Gold Contact

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Wheels and Tires Warning Messages

Pressure

High-priority warnings – sudden pressure loss

Flat Tire!

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1 bar (14.5 psi) (100 kPa)

30

60 Time in Seconds SSP277/130

The wheel electronics send data messages every 54 seconds. If the wheel electronics detect a sudden change in pressure greater than 0.2 bar (2.9 psi (20 kPa)) per minute, it transmits in 850 ms cycles.

Target tire pressure stored via the menu. The system calculates the target pressures relative to 68°F (20°C) from the respective inflation pressures. The pressure falls below the coded minimum pressure of, for example, 1.9 bar (27.9 psi (190 kPa)) for Phaeton with W12 engine. High-priority warning due to sudden pressure loss greater than 0.4 bar (5.8 psi (40 kPa)) below the stored target tire pressure. Dynamic high-priority warning on sudden pressure loss greater than 0.2 bar (2.9 psi (20 kPa)) relative to the last transmitted pressure value.

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Wheels and Tires

Pressure

Low-priority warnings – slow pressure loss

Check Pressures!

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1 bar (14.5 psi) (100 kPa)

30

60 Time in Seconds SSP277/142

The wheel electronics send data messages every 54 seconds. If the wheel electronics detect a sudden change in pressure greater than 0.2 bar (2.9 psi (20 kPa)) per minute, it transmits in 850 ms cycles.

Low-priority warning due to pressure loss between 0.2 and 0.4 bar (2.9 and 5.8 psi (20 and 40 kPa)) below the stored target tire pressure. High-priority warning due to pressure loss greater than 0.4 bar (5.8 psi (40 kPa)) below the stored target tire pressure.

If the driver has inflated the tires to pressures critical to driving dynamics, the system also issues warnings. The difference in target pressures on one axle may not exceed 0.4 bar (5.8 psi (40 kPa)). The difference in target pressures between the axles may not exceed 0.5 bar (7.3 psi (50 kPa)). If the spare tire pressure falls below its stored target pressure by more than 0.4 bar (5.8 psi (40 kPa)), a low-priority warning likewise appears.

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Wheels and Tires Warnings in the Display Unit in Instrument Cluster Y24 The small symbol is always displayed. The large symbol only appears when the “Tire pressure monitor” menu is open. It disappears when another menu opens.

Display during system fault.

Display during the learn phase.

System Is Learning!

System Fault!

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Display when switching off.

Faulty Wheel On Board!

System Switched Off!

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Display during radio fault.

Warning Currently Not Possible!

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Display when faulty wheel on board.

Wheels and Tires

Controls The tire pressure monitoring system main menu appears on the Front Information Display Control Head J523 when the “VEHICLE” function key is pressed. The following functions are stored:

Pressing the key also starts a new learn process for wheel assignment. To avoid receiving from external wheel electronics while learning, the system learns only when travelling faster than 3.1 mph (5 km/h). The learning process is complete after about 15 minutes driving time.

• Switch on/off tire pressure monitoring system. • Switch on/off spare wheel monitoring. • Inflation information. • Adopt current pressures. The driver can specify and set the tire pressures to be monitored within the limits coded according to the vehicle series. After pressing the “Adopt current tire pressures” function button and then confirming the pressures, the system stores the current tire inflation pressures at the current tire inner temperatures for their respective ID codes.

CLIMATE

MAP

NAV

AUDIO

SETTINGS

ON/DARK

RESET

VEHICLE

NAV SET

TRIP DATA

MANUAL

HELP

FM

CD

AM

SCAN

1

2

3

4

5

6

BAL/FAD

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“VEHICLE” Function Key Tire pressure monitoring main menu with high-priority warning for rear right tire

The driver is responsible for correctly setting the tire pressures to be monitored.

TPM Vehicle Spare wheel monitoring

Inflation information

Target pressures in [Bar] at 20°C

Adopt current pressures

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Notes

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Knowledge Assessment

An on-line Knowledge Assessment (exam) is available for this Self-Study Program. The Knowledge Assessment may or may not be required for Certification. You can find this Knowledge Assessment at:

www.vwwebsource.com From the vwwebsource.com Homepage, do the following: – Click on the Certification tab – Type the course number in the Search box – Click “Go!” and wait until the screen refreshes – Click “Start” to begin the Assessment

For Assistance, please call:

Certification Program Headquarters 1 – 877 – CU4 – CERT (1 – 877 – 284 – 2378) (8:00 a.m. to 8:00 p.m. EST) Or, E-Mail:

[email protected]

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Volkswagen of America, Inc. 3800 Hamlin Road Auburn Hills, MI 48326 Printed in U.S.A. August 2003