Power Steering Pump - Groaning

[bpossel]

Happy Holidays!!!

  My power steering pump is making a groaning noise.  Looks like the previous owner did do a seal kit (from Buds) overhaul approx 2 years ago.

[!]The noise started just after I replaced the top round disk seal on the steering gear box.  Thinking the noise is air in the system, I hooked up a hose on the gear box nipple and ran it into the ps reservoir.  Started the car, opened up the nipple and some air bubbles came out through the hose.  I then closed the nipple and rotated the wheel several times left and right to the full stop position.  Then opened the nipple and a very small amount of bubbles came out.  I also left the nipple open while rotating the wheels left and right to their full stop position.  No luck, still a lot of groaning noise…

 :?: Does anyone have any idea what else I can do to fix this?  It may just be that the ps pump went bad, but its just too coincidental that the moaning started after I had the system open.

Help!  Thank you!
Bob


bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

Check the filter..

[bpossel]

Thanks A Dalton,

I replaced the filter a few months ago.  Also note, no leaks, so dont think it is sucking in any air?  I am guessing that air is trapped in the pump and that it cant escape.  Is this possible?

B.

bpossel
Memphis, TN.
1971 280SL
1997 E320

[bpossel]

Just read some other posts indicating that the groaning is due to air in the system and that "proper" bleeding must be followed.  The post said that the front wheels need to be off the ground and to slowly move wheels lock to lock.  When I did the bleeding earlier, I had the wheels on the garage floor and simply turned the wheels lock to lock.

Any comments on needing to elevate the wheels to bleed the air out?

B.

bpossel
Memphis, TN.
1971 280SL
1997 E320

[George Davis]

Bob,

I believe I had the front wheels off the ground when I bled the system after replacing the hoses.  Several slow turns lock to lock did it.  I also used a clear hose, that might be helpful.

George Davis
'69 280 SL Euro manual

[bpossel]

Thanks George!

I raised the front of the car last night and put on jack stands.  I bleed the system again by slowly turning the wheels lock to lock.  Some add'l air (very small bubbles) did escape.  I am using a clear hose.  I bleed the system by leaving the nipple open while moving the wheels lock to lock.  I also bleed the system by closing the nipple and moving the wheels lock to lock, then opening the nipple with the wheels pointing straight ahead.  Again some small air bubbles came out.  The pump is somewhat quieter now, but still makes a groaning noise, mostly when I rotate the wheels to the left.

 :?: What type, brand of fluid does everyone use?  I am just using Dexron III ATF.  I have read posts indicating that some use ATF, and some say to only use "approved" MB power steering fluid.

Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[jeffc280sl]

Hi Bob,

 

Does the noise change if the engine rpms are increased while turning the steering wheel?  Assuming the noise is related to stress on the pump, do you hear the noise when the wheels are off the ground.

In the event there is a relationship between the pump noise and the steering box o ring replacement you may consider adjusting tension on the spring loaded adjusting bolt.  Try it both ways and see if the noise changes.

Jeff C.
1970 280SL 4-speed

[ja17]

Hello Bob,
These systems will usually self bleed anyway.  You may have another problem. Possible leak or a sticky valve in the p.s. pump. Maybe the recent work allowed some dirt particle to work its way back to the pump? I hesitate to point you to the power steering pump because it is buried on these cars. Try everything else first.

Joe Alexander
Blacklick, Ohio

[bpossel]

Jeff, the noise is the same with wheels on and off the ground.

Joe, do I really need to pull the radiator to replace the pump?  Looks like I can slide the pump off the bracket with the pulley attached.  Then remove pulley on the bench.  Obviously, need to remove the hood, battery (and tray) for access, belt and bolts holding pump.  What do you say?

Thanks!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[waltklatt]

Bob,
How is the reservior?  Is it filled with somewhat foamy fluid?  Any deviation from the bright red clor?  Should be atf in there.  Mine did the same too and it was excessive air in the system.  Bled it out by simply turning the wheels back and forth and holding the wheel all the way to the end for a longer period of time.  The motor will slow down a bit and the pump will feel like extra work.  But hold it for a short time and then turn to the opposite direction and hold.  This allows the air bubbles to be flushed out.  If it still groans, then you might want to lube up all the moving joints on the kingpins and front wishbones.
This was on my 220SL for a while(has the W201 190D steering pump) and I did this and it is now very quiet, except a slight jerk when turning to the right, but it smooths out once turning.
Walter Klatt
1967 220SL-diesel
1963 230SL-gas

[bpossel]

Hi Walter,

My system has regular ATF in it.  The reservoir doesn’t have foam in it, rather just some small bubbles once in awhile.

  I tried what you suggested and pump is still making a noise.  What I think may have happened is that when I replaced the top seal on the gear box, I may have loosened up some old dirt in the system by tapping on the disk to get it open.  I have flushed the system out 2x’s since and the fluid is nice and red.  Just some bad luck….  The pump is no good.

  I have a rebuild pump on order and should have it replaced by next weekend.  Will update the site with the results….

Walter, thanks for your feedback and have a Merry Christmas!
Bob


bpossel
Memphis, TN.
1971 280SL
1997 E320

[waltklatt]

Thanks Bob,
Merry Christmas to you too and to everyone else too!
Be safe with yourselves and your Pagodas!
The pump replacement is solution to the culprit.  Let us know how it goes after your replace it.  By the way, the pump should be the same as the sedan cars, correct?

Happy Holidays to all!
Walter Klatt
1967 220SL-diesel-with a red ribbon on it for a christmas gift to my parents
1963 230SL-gas, under a cover

[bpossel]

Hi Walter,

Not sure if pumps are the same?  I do know that there are 2 different pumps for the 113's.  An early pump with a straight pulley shaft and a later pump with a conical shaft.  I believe '69 and later was when the conical shafts were used.
Will keep y'all posted...  Hope I can pull the pump w/o radiator removal.  Just just this all back together with a new water pump a few weeks back...
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[ja17]

Hello Bob,
There are some additional difficulties removing the pump with the radiator installed. You may not save time in the long run. However the biggest hurdle is loosening the nut and removing the pulley. A special puller is specified in the BBB. You cannot connect the special puller with the pump and radiator installed. Unfortunately some of the attachment bolts for the pump are behind the pulley!

It can be done however you will have to use the "pry method" for removing the pulley. You can bend the pulley if you are not careful! Also you may have to loosen the 10mm radiator mounting bolts and slide the radiator as far forward in the slotted holes in order to gain enough clearance between the pulley and the radiator.

The pump and pump bracket cannot be removed as a unit since some of the bracket mounting bots are behind the pump! The removal sequence must be remove the pulley then the pump without the bracket.

Some other tips; loosen the 22mm pulley nut before removing the fan belt! one of the rear 14mm pump bolts will need to be removed since it secures the pump to the bracket (do not loose the spacer), the two 17mm bolts in between the pump and the pulley can be partially removed until they actually push on the pulley, the special adjuster with the two 10mm nuts will also have to be dis-engaged.

Hope you're problem is in the pump before going to all this work!



Joe Alexander
Blacklick, Ohio

[bpossel]

Thanks Joe!

I am going to do this the right way and remove the radiator and use a pulley extractor.  Dont want to damage anything if it can be avoided.
Merry Christmas!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[bpossel]

Update...

I removed the hood, battery & holder, and radiator.  I was then able to get a better look at the power steering pump.  Well, I noticed what may have been the cause of the groaning noise.  When I replaced the water pump recently, I also replaced the short bulk hose that connects the bottom of the power steering reservior to the pump The old one looked just that...  old).  Well, this short hose, which takes virtually a 90 degree bend to perform its function, was kinked almost completely at it's bending point.  So I would imagine that the fluid was being restricted to the pump by over 90 percent.

Since I have it all apart and the new pump ordered, I will still go ahead and replace it.  I went to Autozone and bought a short, 90 degree, preformed hose that will fit, so no more kinking... I also borrowed a small puller that had 3 arms on it.  I used this to remove the pulley (no way to have done this with the radiator on!).  I couldnt use the bolt that came with the tool, it was too long.  I used a shorter bolt (~2 inches) that I had in my cabinet.  It only took a couple of turns on the bolt on the remover tool and the pulley popped right off.  I was careful not to bend the outer ring of the pulley.  The best tool would be one that is able to connect to the small groove, close to the pulley center and main shaft bolt (as referenced in the BBB).  Since I knew that my pump was rebuilt a couple of years ago by the previous owner, and the pulley was off before, it came off very easy.

I will take some pics and post later.
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[ja17]

Hello Bob,
Make sure the hose you used is rated for this fluid. If you use coolant water hose it will not last.

A new pump? Very pricey I suspect. Why such a drastic fix, rebuilding these is much easier than the steering gear box?

Merry Christmas!


Joe Alexander
Blacklick, Ohio

[bpossel]

Hi Joe,

I ordered a rebuilt pump from Arizona Autohaus.  I didnt order a new one.  Still more than doing the rebuild myself, but I just didnt feel like messing any more with this.  Want to drive the car and take a break from the continual repair and improvements.

Thanks and Merry Christmas!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[n/a]

bpossel

I had a similar problem after reassembling my car.  I solved it by bleeding the air from the system as outlined in the BBB.  

Good luck

Iverson

[Raymond]

What's the difference between Power Steering Fluid and ATF and why does it make a difference in our cars?

Ray
'68 280SL 4-spd Coupe

[bpossel]

Here is a picture of my rebuilt power steering pump going in.
So far, so good.  Had to remove one of the rear bolts from the new/rebuilt pump (thanks Joe!) and use my existing longer bolt with spacer in its place.  Also carefully tapped out the old "key" from the old pump's shaft.  The new/rebuilt pump did not come with a new key for the shaft/pulley.
 
More to come...
Bob

Download Attachment: rebuilt.jpg
50.83 KB

bpossel
Memphis, TN.
1971 280SL
1997 E320

Download Attachment: rebuilt2.jpg
54.04 KB

[jeffc280sl]

Sounds like your making good progress. I did that job a few years ago.  The pump was groaning so I replaced it as you are.  That improved the pressure and caused the steering box to leak in the same place as yours.  Unfortunately I didn't know one could replace the o ring so I removed the box and rebuilt it. Live and learn.

Jeff C.
1970 280SL 4-speed

[bpossel]

Update.

Finally got the new/rebuilt PS pump fully installed, radiator back on and car back in operation.  It is amazing at how quiet the new pump is.  Even when I turn the wheels to their full lock positions, no noise.  What was also interesting is that no air bubbles came out when I bled the pump.  

Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320