Steering: Testing and Inspection
WM 4890IN Test and assembly work on power steering
General information
Information
- The pictures shown in this document may differ from the original.
- However, this does not affect the validity and relevance of the pictures.
Information
- The rack-and-pinion steering gear and power-steering pump must not be repaired or dismantled!
- Always replace the O-rings on hydraulic lines!
- Ensure absolute cleanliness at all times!
- The reservoir must always be replaced if individual or multiple components, such as the tandem pump, PDCC valve blocks (FA/RA), PDCC anti-roll bars (FA/RA) are replaced.
- If system faults still occur after replacing a component (another component is defective), the reservoir does not have to be replaced again.
- Steel flexi-pipes must not be kinked or crushed.
- Observe safety requirements! -> 4303AW Safety requirements for Porsche Dynamic Chassis Control (PDCC) Service Precautions
Damage to the power steering will occur if there is a shortage of oil in the hydraulic system. Even small leaks can cause the fluid to escape and damage the servo pump as a result of the high oil pressure in the hydraulic circuit.
Grunt-like noises that can be heard when the steering is locked, or foam formation in the reservoir indicate a shortage of oil and/or that air has also been sucked in. Before filling the reservoir, however, any existing leaks must be eliminated. In this case, the oil level in the reservoir must be checked when the engine is running and when it is stopped! If the oil level drops to the bottom of the reservoir or bubbles rise up, then there is air in the hydraulic system.
Only Pentosin CHF 202 may be used in the reservoir. Pentosin CHF 202 can be ordered under the following part number: Quantity supplied 1 litre = 000.043.203.33.
A dipstick with MIN/MAX markings is attached to the reservoir cap => Dipstick with MIN/MAX marking (shown as an example). The markings are for a fluid level on a cold engine (approx. 20 °C)!
Dipstick with MIN/MAX marking (shown as an example)
Checking
Checking power-steering fluid level
CAUTION
Increased risk of accidents and material damage if too much Pentosin CHF 202 is filled in or if Pentosin CHF 202 comes into contact with the coolant hoses when filling or topping up.
- It is possible to overfill the system, causing Pentosin CHF 202 to overflow onto coolant hoses and other components.
-> Before checking the fluid level, run the engine for approx. 20 seconds. Multiple steering operations (manoeuvring) will change the fluid level in the reservoir. Check the fluid level.
-> If coolant hoses come into contact with Pentosin, clean them thoroughly with water IMMEDIATELY.
-> Replace visibly swollen coolant hoses.
Information
- The reservoir is located in the engine compartment, at the left.
Reservoir in engine compartment (shown as an example)
- A dipstick with MIN/MAX markings is attached to the reservoir cap. The markings are for a fluid level on a cold engine (approx. 20 °C).
- The MAX marking can easily be exceeded at higher temperatures.
Check the fluid level (Pentosin CHF 202) when the engine is not running and when it is cold (approx. 20 °C).
The fluid level must be between the MIN and MAX markings => Dipstick with MIN/MAX marking (shown as an example).
Dipstick with MIN/MAX marking (shown as an example)
1. Start the engine and run it at idle speed for approx. 20 seconds. Switch off the engine.
2. Open the engine cover and reservoir.
3. Wipe off the dipstick. Close the cap and then open it again. The fluid level must be in the indicated range (MIN/MAX level at approx. 20 °C). Top up with Pentosin if necessary.
Bleeding
Bleeding the steering system
1. After installation is complete, raise the vehicle so that the wheels are no longer touching the ground.
2. Open the engine cover and reservoir.
3. Fill the reservoir up to the MAX marking until the level no longer drops.
Engine is not started!
4. Turn the steering fully to the left and right and hold it at full lock for approx. 30 seconds on each side until the level no longer drops. Continually check the fluid level and fill to the MAX marking again.
5. Lower the vehicle onto its wheels.
6. The next procedure causes the fluid level in the reservoir to fall rapidly, so constantly add Pentosin CHF 202 (2nd mechanic required!).
The reservoir must not be sucked dry.
7. Start the engine and leave it running for approx. 1 second. Top up continually with Pentosin.
Repeat the procedure several times until the fluid level no longer drops.
8. If the fluid level in the reservoir does not fall any further when the engine is briefly turned over, start the engine and leave it running at idle speed.
9. Turn the steering on full lock several times to the left and right at idle speed and hold it at full lock for max. 1 second. Observe the fluid level (a second mechanic is required). Continually add fluid until the level in the reservoir remains constant and no more air bubbles circulate in the reservoir when the steering wheel is turned.
10. Switch engine off and set the correct fluid level. This must be between the MIN and MAX markings.