Power Steering Bleeding: Service and Repair
Test and assembly work on power steeringGeneral
Note!
^ Rack-and-pinion steering gear and servo pump must not be re paired or dismantled!
Damage to the power steering is caused by 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 occurring 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, any existing leaks must be eliminated on the suction side. Alternatively, the defective part on the pressure side should be replaced.
Only Pentosin CHF 11 S may be used in the reservoir. Pentosin CHF 11 S can be ordered with the following part number: Quantity supplied 1 litre = 000.043.203.33.
A dipstick with MAX-MI N markings is situated on the cap of the reservoir. This is valid for the liquid level with cold engine, i.e. approximately 20°C.
Checking the fluid level for the power-assisted steering
Caution! Danger of damage to property if too much Pentosin CHF 11 S is filled or if Pentosin comes into contact with the coolant hoses when filling or topping up.
^ Observe the following specifications in order to avoid overfilling and thus overflowing.
^ Prior to the fluid level check, run the engine for approximately 20 seconds. Multiple steering operations (maneuvering) charge the fluid level in the reservoir! Check the fluid level.
^ If coolant hoses come into contact with Pentosin, thoroughly clear/ them with water IMMEDIATELY.
^ Replace visibly swollen coolant hoses.
Note!
^ The reservoir is located at the front left of the engine compartment.
^ A dipstick with MAX-MIN markings is situated on the cap of the reservoir. This is valid for the fluid level with cold engine, i.e. approximately 20°C.
^ The MAX mark can easily be exceeded at higher temperatures.
Pentosin tank in the engine compartment
Check the fluid level (Pentosin CHF 11 S) when the engine is not running and when it is cold (approximately 20°C).
The fluid level must be between the MAX and MIN markings.
1. Start engine and run it at idle speed for approximately 20 seconds. Switch off engine.
2. Open the engine cover.
3. Open cap of the supply tank.
4. Wipe off the dipstick. Close and then reopen the cap. The fluid level must be in the designated range (MAX/MIN level at approximately 20°C). Top up with Pentosin if necessary.
Bleeding the steering system
1. After installation is complete, raise the vehicle so that the wheels are no longer touching the ground.
2. Open engine lid, flap and reservoir.
3. Fill reservoir up to the MAX marking, until the level no longer drops.
4. Then turn the steering to the left and to the right. Hold the steering on full lock for approximately 30 seconds at each side until the level no longer drops. Continually check the fluid level and fill to the MAX marking again if necessary.
5. Lower vehicle onto wheels. Briefly start the engine, let it run for approximately 1 second and add Pentosin again. This procedure causes the fluid level in the reservoir to fall rapidly, so constantly add Pentosin CHF 11 S. The reservoir must not be sucked dry.
6. If the fluid level in the reservoir does not fall any further when the engine is briefly turned over, start the engine and let it run at idling speed.
7. Turn steering on full lock to left and right at idle speed and hold there briefly.
8. Observe fluid level during this procedure. If it continues to fall, add fluid until the level in the reservoir remains constant and no more air bubbles rise in the reservoir when the steering wheel is turned.
9. Switch engine off and adjust correct fluid level. The fluid level must be between the MAX and MIN markings.
When the correct level has been reached, no air bubbles should be circulating in the reservoir and the fluid level should no longer drop.