I have a scraping/grinding noise that appears
to be comming from the back of the power steering pump, most noticable at low RPM.
The noise will come and go, does not seem to be temp dependant. No leaks and steering works fine, doesn't get worse when wheels
turned to lock. I don't know if the fluid has ever been changed could this be a probable cause? It is a ZF pump, is it easily rebuilt if that is necessary?

PS. This is my first post but I have found several usefull tips here that have helped me
save $$ while I improve my car.

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Dave
88 300E 130K

Hate to sound like DUUUH, but are you sure it's the power steering pump. Is the oil level in it OK ??. Is the scraping/grinding metallic in nature? I've never heard fluid get crunchy unless it has something suspended in it. Unscrew the cover, poke your finger in the resevoir and see if there are any metallic bits suspended in the fluid. PLEASE DO THIS IMMEDIATELY AFTER SHUTTING OFF THE ENGINE, NOT WHILE IT'S RUNNING. Now as I lower my voice, I wish you a Happy Easter and Good Luck

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Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 04-20-2000).]

I have isolated this by using a mechanics stethoscope. The noise is loudest at the back of the pump. It can be heard from inside the car when idling. When run with the belt off there is no noise. There does not appear to be any metalic particles in the fluid, it appears thicker than fresh ATF though. Perhaps the noise is just a pump with 130K but after thinking a ticking noise was just a worn lifter and having to rebuild the head with new rockers, lifters, cam, etc.($2K)to correct it (second cam in 18K) I get a little nervous when I hear a new noise.

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Dave
88 300E 130K

Try flushing the old fluid out of the system and replace the fluid and the filter in the reservior and see if the noise goes away, if so, great! If not, you'll need to consider a reman. pump.

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ASE Master Technician, Lead Technician for Deutsch American Inc. Over 6 years of Import experience-specializing in German Automobiles.

Dave, remove the belt and give the pully a feel, if there's any movement beyond the normal rotational type then a bushing has gone south, probably the rear pump rotor support, which if it develops any excessive lateral clearance, will cause the pump impeller blades to strike the stator housing at an abnormal angle->grinding noise. BTW you mention the fluid doesn't look like ATF, what do you think it is? Also, if I read you correctly, did you get hosed on a upper end overhaul b/c of one noisy lifter or did the engine really need the work?

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Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 04-21-2000).]

I picked up a filter last night and will try flushing the system theis weekend. I will also look for any unusual play in the pump.
As far as the upper end overhaul, the cam had
two lobes ground off and four of the rockers were damaged. I purchased the car with 92K
(3rd owner) trying to eliminate an occasional rough idle I found a damaged cam and had it replaced @ 108K. At 127K I had what I thought was a noisy lifter or two. Two lobes worn off on the cam and several rockers damaged.
The shop that did the original work also did the rebuild for 10 hrs labor and parts at $1250. This was new guides, rockers, rocker shafts, lifters, cam, cam gear, chain, gaskts
& machine work. I pretty much wrote off the first cam to probable poor maint by one of the previous owners, but the second seemed to me that something was missed or done wrong during the first repair. I have not been able to find any other complaints about cam
problems on a 300E. The shop that I use is
an independant shop but has a good reputaiton
and I have dealt with them for 5 yrs with this being the first problem. They charged
just less than what I could get the parts for
from Performance and I thought the labor was reasonable for what they did. I just hope that something has not been missed that will cause this again.

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Dave
88 300E 130K