Power steering pump

[Dave Gallon]

Well, I must apologize for not checking my facts and going strictly from memory. I thought the O-ring was flattened, oval in cross section. However, I just checked the O-ring I have in stock and it appears to be simply round in cross section. I also have a couple of the repair kits that include the piston and O-ring; again, the O-ring looks to be round. So, Ron, I am sorry to have caused heartburn, I think what you have done is fine. The O-ring may be special in some way but it is round in cross section.

[Ron]

Thank you Dave!  Sometimes trying to put together this car, and growing old, I feel that my brain has lost what little it had in the way of reasoning power.  I'm guessing that the O ring acquires the "D" cross section as it ages in that piston bore.  Maybe as uniqueness it is a really tough "O" ring, for one thing it will not allow itself to be turn "inside out" like a regular O ring.

Since I know so little of procedure here, Dave, could you PM me on how to order from you?  My email is Zeppo2K2@yahoo.com.

Now I just have to figure out the pulley/woodruff key issue when my pulley arrives from Dan.  (and then on to steering shaft bushings, heater core mounting repair, passenger door window guide reglue, put the engine in, and see if I can take a drive!  Or what else is lurking in that pile of parts?)

Ron

[waqas]

Finally completed the power steering pump rebuild. The pressure regulator piston assembly is pictured below. Strangely, the ID of my replacement "special" O-ring 000 997 74 45 was a bit looser than the original, but the OD was a good fit in the bore. Is this normal?

[waqas]

To wrap-up the thread, I've had the rebuilt pump in the car for several days now, with no problems so far.

Regarding the hose elbow, I ended up loosening the PS reservoir and turning it CW a little bit, and the elbow became managable by the existing hose (bulk PS hose from MB) without the need for the unicoil. Neat idea though.

[awolff280sl]

Waqas, recheck that PS hose after putting a few miles on the car. I did the same thing with rotating the reservoir to take the bend out of the hose, but the bend redeveloped over time, so I went with the Unicoil.

[saygold]

I am rebuilding my power steering pump at this time.  Unfortunately, I did not locate the small o-ring when I disassembled it.  I found it "loose"  on my work table after i was looking over everthing.  It appears that the o-ring should be in the center of the housing behind the plate shown in Weqas's attachment.  Could someone confirm the small o-ring location?

Thanks in advance for your help.

Ken Deter
'66 230SL (euro, 4-speed)

[waqas]

Ken, I sent you a PM as well.

Regarding the PS pump, there are two o-rings that are located where the two halves of the main housing mate together.
Photos are located in this post: http://www.sl113.org/forums/index.php?topic=10980.msg73665#msg73665
The 3rd and 4th photos show the two halves of the main housing. Notice there are two circular mating points? The small o-ring fits in the smaller mating depression.

I don't believe there is any o-ring that goes behind the plate, as far as I can recall.

[waqas]

Ken,

I edited one of my photos to show the locations of the two O-rings that come with the kit. Is this what you're talking about?

[saygold]

Waqas,

Thanks for the information - it is rather obvious now.  I was looking for a small groove similar to the large o-ring location. 

Ken
'66 230SL (euro, 4-speed)

[waqas]

When re-assembling the pump, remember that the little vanes should be installed in a particular orientation: the square edge faces inward, and the round edge faces outward. Here, inward and outward are relative to the center of rotation of the pump.

So far, my pump seems to be working fine (driving almost everyday). I'll probably need to bleed the PS system again, as my hydraulic idle lift mechanism is not working quite right.

[tel76]

Hello Waqas,
Will you please clarify a small point regarding photograph #3?
Did you replace the oil seal with the shaft in position?
and if so Is it not possible to remove the drive shaft and bearings?
Great informative article

[waqas]

Did you replace the oil seal with the shaft in position?

Yes.

and if so Is it not possible to remove the drive shaft and bearings?

I'm sure it is, but I did not try. Perhaps someone else can chime in if they know how. I placed the shaft in a vice and spun the housing. The bearings seemed to be fine, without any obvious dead spots. I was a bit pressed for time, so I opted not to mess with the bearings and the bushes in there.

FYI:
To pull out the front seal, I stuck a screwdriver between the seal and the shaft, wedged it under the seal's metal sheath, and then levered it out (applying leverage against the front of the pump housing). I was able to do this without applying any pressure to the shaft itself, for fear of damaging or scoring the shaft. A seal puller did not work, as the seal was pretty tight in there. I tapped in the new seal with a deep socket of the correct diameter.