Bleeding the power steering system (Mercedes-Benz E-Class W124)

With the engine off, fill the fluid into the reservoir to the upper level mark on the plastic tube that is installed on the reservoir cap stand. With the engine off, slowly turn the steering wheel from lock to lock several times to remove air that has entered the hydraulic system, then add fluid to the reservoir. Repeat this operation until the fluid level in the reservoir begins to decrease.

Start the engine and observe the fluid level in the feeder tank. You may need to add fluid to the feeder tank after starting the engine.

With the engine idling, slowly turn the steering wheel 2 - 3 times approximately 45° to the left or right of the center. Then turn the steering wheel left and right from lock to lock. Do not hold the steering wheel in the extreme positions, since the pressure in the hydraulic system is at its maximum. Repeat this operation until air bubbles no longer appear in the feeder tank.

If the power steering system makes a noise when turning the wheel, there is still air in the system. This can be checked by turning the steering wheel straight ahead and turning off the engine. If the fluid level in the reservoir increases, there is air in the system and it needs to be bled.

After bleeding the hydraulic system, turn off the engine and allow it to cool. After the engine has cooled, check the fluid level in the expansion tank and add fluid if necessary.