Steering: Testing and Inspection

CHECKING THE FLUID LEVEL FOR THE POWER-ASSISTED STEERING

Notes on power-steering fluid
Damage to the power-assisted 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.

Note:
Only Pentosin CHF 11 S may be used in the reservoir. Pentosin CHF 11 S can be ordered under the following part number:
Quantity supplied 1 litre = 000.043.203.33.

Checking fluid level for power-assisted steering
The reservoir is located in the engine compartment.
There are 2 marks on the dipstick located on the cap. There is a Cold mark for when the engine is cold: approximately 20°C and on the other side for when the engine is hot: approximately 80°C

Check the fluid level (Pentosin CHF 11 S) when the engine is off and cold: approximately 20°C

1. Start engine and duration approximately 20 seconds allow to run at idle speed. Switch off engine.
2. Open engine cover. Open reservoir cap.
3. Wipe off the dipstick. Close and then reopen the cap. The fluid level should lie in the hatched area beneath the Cold mark (mark maximum level) at Cold mark approximately 20°C Top up with Pentosin if necessary. The upper Hot mark is intended for a fluid temperature of Hot mark approximately 80°C
Do not add too much Pentosin! The respective marks are for the maximum fluid level at the COLD or HOT temperature.
If assembly work was performed previously, check fluid level with the engine idling and without operating the steering.

Multiple steering movements (maneuvering) with the engine switched off changes the fluid level in the reservoir - fluid level rises. In this case, the engine must be run for at least 20 seconds immediately prior to the fluid level check.
When topping up or filling in Pentosin, make sure that it does not come into contact with the coolant hoses! If coolant hoses come into contact with Pentosin, thoroughly clean them with water IMMEDIATELY! Replace visibly swollen coolant hoses!

Checking the steering system for leaks (visual check)
With engine idling, turn steering wheel as far as the stop and hold still. The maximum possible line pressure results in this way.
In this position, check all pipe connections for leaks.
Carry out testing for a maximum of 10 seconds. A longer check should always be interrupted by a brief pause after approximately 10 seconds.

Bleeding the steering system
1. Fill the whole system after the installation of new steering components or lines or after a substantial loss of hydraulic fluid, briefly start the engine a few times and, when it fires, switch it off again immediately. 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.
2. 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.
3. Rapidly turn the steering wheel from full-lock to full-lock several times so that the air can escape from the cylinders. At the end positions of the piston, do not pull the steering wheel with more force than is necessary in order to turn the steering (to prevent unnecessary build-up of pressure initially).
4. 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.
5. Correct the fluid level with the engine at idling speed and without moving the steering.