How to replace leaking rear seal on power steering pump - A Pictorial
This write up is for the ZF pumps found on the 616/617 engines. The featured pump is off an '82 240D.
I have a ZF pump that was leaking from the large O-ring on the rear of the pump. To replace the seal, you have to remove the pump and partially disassemble it.
Pump is removed from car and you are looking at the back of the pump. There is a large snap ring which may be difficult to see in the picture which you will eventually have to remove.
View of front of the pump. I went ahead and removed the pulley to get access to the front seal. You don't have to remove the pulley to just replace the O-ring at the rear of the pump. Simply use an impact gun to remove and later reattach the pulley nut.
You will need a large 3 jaw puller to remove the pulley if you so choose. It may be stuck so be careful you don't bend the pulley. Use heat to help facilitate removal if necessary.
You will need a 6-inch C - clamp to compress the rear cover of the pump to remove the rear access plate. After compressing the cover, remove the snap ring. Note the orientation of the snap ring for later reinstallation.
Snap ring removed.
My cover was a little stuck so I used vice grips to help pull it off.
Cover is removed and your O-ring sits right in there. Pull it out and put the new one in.
The pump is attached to the engine via three bolts. Two on the top and one on the bottom.
You'll need to bleed the pump when you're done. Jack up the front of the car so both front wheels are off the ground. Fill the pump up, put the lid on, start the car and turn the wheels side to side to full lock a few times to bleed the air out. Turn off the car, remove the lid and add fluid as needed.
Discuss this DIY here.