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antonross 05-08-2019 09:54 AM

Whining/Groaning Power Steering Pump

My 1985 380SL has been sitting for a month or so, and I just had her detailed and ready for Spring here in the Bay area. She started right up, but I immediately noticed a bit of whining/groaning when turning the wheel, and it was somewhat "heavy."

I checked the PS fluid reservoir, and it was topped off, and I couldn't find any evidence of leaks anywhere.

Is the PS pump possibly failing, or could it be a blocked filter at the bottom of the reservoir?

Just wondering what else I should check before escalating this to my mechanic.


okyoureabeast 05-08-2019 11:39 AM

How's the health of the belt?

A loose belt might not provide enough for the pump.

Or because you didn't drive the car for a bit, the grease in the boots on the steering linkages need to be redistributed. Or a lower end component or bushing has gone bad in that same location.

If the belt looks ok, I would keep driving the car and see if it goes away. Remember, these vehicles don't like sitting. They need to be driven or else they get cranky.

antonross 05-08-2019 03:30 PM

Belt health is good. I replaced belts, plugs and wires at 100K (about 20K miles ago), and I visually and manually inspected the belt per a recommendation I read here yesterday.

The sound (groaning when I turn the wheel lock to lock) and heaviness of the steering makes me suspect that she (Ava von Gartner) is cranky from having sat too long.

I'll keep driving her around the island (Alameda Island, SF) this weekend, and then to work(60 miles R/T) next week and see if it clears up.

If not, I'll report back here for recommendations and next steps.

As always, I fully appreciate the support and insight from all your 107 drivers and techs!

Many thanks!

plinker17722 05-09-2019 01:46 AM

I used to have this after winter lay off . So i sucked all the oil out removed the filter so i could get in to the bottom of the pump with a syringe to suck out as much out as possible. Then i replaced the filter toped it back up . Run the car engine . Turn the wheel left and right a few times to remove the air . Then do the same again without removing the filter in a few days time . And did this till i had used up both containers of pas fluid ,. You can watch it done on youtube video but thats by removing a return hose from the pump.

antonross 05-09-2019 09:10 AM

Excellent suggestion if her pump continues groaning.

I drove her to work today (about 25 miles—Alameda Island to Hercules, CA) and she groaned more after starting up, which gradually got softer. Still a bit of groaning when I got to work, but far less than at start-up.

I'll update in a few days if she's still groaning a lot.

Thanks, all!

plinker17722 05-09-2019 10:08 AM

May be a little air in the system, Or an oil change and filter change on the books .But do how i said and it will get rid of the noise .It worked for me .

antonross 05-09-2019 10:16 AM

Air sounds like a possibility.

The oil is pretty clean (as is the filter) since I did an oil change/filter right before leaving Hilton Head Island for San Francisco...roughly 1K miles ago.

As always, appreciate the input!

plinker17722 05-09-2019 10:35 AM

Well sounds like air in the system . Pull the car on to a gravel surface then you can turn the wheels laft to right with out to much pressure on the steering knuckles and ball joints. The right way is to get the front wheels up and off the ground ,,and then do the left to right bit to bleeding air out of the system.Dont hold the steering wheel on full lock for more than 3 seconds . Then use the car as usual but If the noise is still with you after a time it might mean that the pump seals need replacing or even a pump rebuild kit and refurb it. The noise can develope if a ball joint is bad ,, in that i mean tight and it is puting presure on the pump to turn the wheels left or right .But with the wheels off the ground you should see and hear it if thats the problem after turning the wheel by hand left to right

antonross 05-09-2019 11:22 AM

Again, excellent suggestions.

I have some gravel here near my office, but I also have a 2.5 ton jack in the boot (the OEM one is a POS) so I'll try this later today.

Many thanks!

plinker17722 05-09-2019 11:29 AM


Originally Posted by antonross (Post 17781536)
Again, excellent suggestions.

I have some gravel here near my office, but I also have a 2.5 ton jack in the boot (the OEM one is a POS) so I'll try this later today.

Many thanks!

My pleasure Trev uk

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