DESCRIPTION & OPERATION
All models are equipped with variable power assist. System has an electronically controlled flow control valve integrated within the steering gear box. Valve is regulated by an servotronic control unit. The servotronic control unit controls the valve to reduce hydraulic pressure to the steering gear at high speeds, and increase hydraulic pressure at low speeds. Increased hydraulic pressure decreases steering effort at low speed. Decreased pressure increases steering effort at high speeds.
Steering system also uses a belt-driven vane type hydraulic pump, rotary piston pinion gear assembly and an oil reservoir. The pump mounts on the front of the engine. Two different rack designs are used. (Scheme 30)and (Scheme 42). Steering links are attached to a bracket on end of rack.
TROUBLE SHOOTING
A malfunction in the electronically controlled power steering system will usually result in hard steering at driving or over-sensitive steering during high speed driving. These problems do not necessarily indicate a malfunction in the electronic power steering system. Before trouble shooting the electronic power steering system, always check the following
- Tire pressure.
- Suspension and steering linkage lubrication.
- Front wheel alignment.
- Steering system and suspension ball joints.
- Bent steering column.
- Power steering system leakage.
- Power steering pump pressure.
If all items have been checked and found to be okay, problem can probably be traced to electronic power steering.
LEAKAGE TEST
| CAUTION | Steering system must be checked for leaks after service work, and when hydraulic oil is missing from reservoir. |
- Run engine at idle.
- Turn steering wheel from lock to lock position, holding briefly at full lock on each side (max. 20 seconds).
- Visually inspect for leaks as follows: Loosen clamp on boot and slide boot to one side. Inspect both left and right steering rack seals. Steering gear rotary valve housing. Power steering pump. Line and hose connections.
SERVOTRONIC ELECTRICAL TESTING
Note. On some models, Servotronic Control Unit may be located behind the glove box.
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RESERVOIR CAPACITY
Lubricant capacity is approximately 28 oz. (0.85 L).
FLUID TYPE
Use Audi Hydraulic Fluid (G 002 000).
HYDRAULIC SYSTEM BLEEDING
- Raise and support vehicle. With engine off, turn steering wheel lock-to-lock several times, allowing air to escape.
- Idle engine for 2 minutes with wheels in straight-ahead position. When no bubbles appear in reservoir, shut off engine and check reservoir fluid level. Fill if necessary.
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Removal & Installation
For removal and installation procedures, see. (Scheme 18) - (Scheme 26)
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Scheme 30
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STEERING GEAR (SERVOTRONIC)
Note. For overhaul procedures common to both types of steering racks (Scheme 36)- (Scheme 41).
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Scheme 41
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Scheme 44
TORQUE SPECIFICATIONS
| Application | Ft. Lbs. (N.m) |
|---|---|
| Bulkhead Nut (1) | 33 (45) |
| Power Steering Pump Hose Fitting | 37 (50) |
| Power Steering Pump Mounting Bracket Bolts | 18 (25) |
| Power Steering Pump Pulley Bolt | 18 (25) |
| Steering Gear Cover Bolt | 15 (20) |
| Steering Gear Damper Nut | 26 (35) |
| Steering Gear Damper Bracket Nut (1) | 33 (45) |
| Steering Gear Damper Bracket Bolt | 33 (45) |
| Steering Gear Damper Socket-Head Bolt | 30 (40) |
| Steering Gear Pressure Hose Bolt | 30 (40) |
| Steering Gear Return Hose Bolt | 30 (40) |
| Steering Gear Socket-Head Bolt | 15 (20) |
| Steering Gear Valve Housing Socket-Head Bolt | 15 (20) |
| Steering Rack Cap | 37 (50) |
| Tie Rod Carrier Nut (1) | 30 (40) |
| Tie Rod End Nut (1) | 22 (30) |
| INCH Lbs. (N.m) | |
| Servotronic Solenoid Valve Bolt | 27 (3) |
| Power Steering Pump Bracket Bolt | 89 (10) |
| Intake Manifold Mounting Bolt | 89 (10) |
| (1) Nut is self-locking. | |
| (1) | Nut is self-locking. |
TORQUE SPECIFICATIONS
WIRING DIAGRAMS
Note. On some models, Servotronic Control Unit may be located under the rear seat, on the right side.
