P/S pump seal job 400E Question
 

My power steering pump is leaking and from searching archives appears to be quite common on these models and only involves the front seal. Question: Do I have to remove the entire pump assembly or can I simply remove the front cover to replace the necessary seal? I would appreciate any tricks/tips for this model as it is a little tight in the engine bay and I haven't really had the need to do anything on the car except fluid changes (I did ascertain that I could get a wrench on the line end fasteners). Would also appreciate any assistance regarding the availibility of any aftermarket seals that may work better as it appears that Mercedes has not redesigned/improved the replacement seals.

All help appreciated.

Anyone?
 

Anyone?

YA, THATS RIGHT, THEY ONLY LEAK FROM THE FRONT SEAL. HAVE FUN!!!!!!!!!!

I've never replaced a seal with the pump in place, but if there is enough clearance in that chassis, it should be no problem.

To keep this from happening again, make sure not to use ATF for PS fluid. It may very well be that your owners manual calls for ATF, but the formulation of ATF has drastically changed in recent years. Mercon/Dexron will cause seal problems in the PS system.

Good luck,

Yes, it can save you a lot of times if you only remove the front half of the pump, remove the pully and disconnect hoses, then have fun with those 3-4 bolts.

When you remove the front half, the inside of the pump will go with the front, leaving only the base in the bay. I used the P/S rebuilding kit here from Fastlane.

Thanks.
 

Thanks for the help. Larry: I haven't had the car that long but replaced the fluid when I got it about 20K ago with factory fluid. The old fluid was of course darker but was not red so I assume it was the factory fill. I guess it is all the heat in the overstuffed engine bay that kills all this stuff (tensioner, etc.).

M.G.: No leaks at the hose fittings, to where else are you referring?

I happen to have a pump for my S420 sitting in the garage. If you need me to look up something about it or take photos for reference, just let me know. It's new so please don't ask me to take it apart.

Sixto
95 S420
87 300SDL

Thanks Sixto. Not sure when I will be attempting this as I am just letting the car sit in my garage for now as it is also due for its 120K fluid change which I will do at the same time when I get actually get some time for all of this. I appreciate the offer and will let you know if I need pics once I get going on it.