Help wanted on refurbishing power steering box

[mdsalemi]

http://candmhydraulics.com

Just in case, those guys are the premier remanufacturers of Mercedes-Benz steering boxes…so if your struggle gets out of hand, the usual gang of suspects such as Bud's, Millers, Autohauz AZ and more can set you up with a fully and professionally rebuilt box. They don't sell direct but through the normal retail channels. When you put it all back together and you find two balls on the garage floor, it still leaks, or it doesn't work, time for an exchange...

[George Des]

Harry,

The valve assembly under the cap has to be removed before you cN extract the shaft assembly. I have the assembly/disaasmbly instructions for this box somewhere and will summarize how to go about doing it if I can find them. In the meantime you may want to look further through the Forum and tech manual. As I recall most of the past discussions some of us had on steering boxes pertained to the power steering box and not the manual one. Also, the power steering boxes on the 113s and 108s and perhaps the 111s and 112s are essentially the same boxes internally even though they carry slighlty diiferent numbers. The differerences are primarily cosmetic on the unit castings as far as I can tell but the units are pretty much interchangeable.

[tel76]

The piston that the spring locates on appears to have rust on it , turn the box upside down and spray with penetrating oil, leave overnight.
Wrap masking tape around the stub that the spring locates on and use a pair off grips to turn the piston and remove it from the housing ( the  O  rind around the piston is very tight).
The aluminium housing on top ( if all the attaching points have been removed)  is being held on by the old gasket, go around the joint with a thin knife, it will eventually separate.
You can then remove the shuttle valve and your journey can continue.

[Harry]

I was finally getting back around to the PS Box this evening, setting pre-loads in accordance with the hand drawn instructions from this post.  (Very nice by the way.)  The front bearing seems to go well.  I couldn't get comfortable with the round nut and hex nut on the pitman shaft, though.  The instructions say to "fit the round nut to it's stop".  I found that the stop seemed somewhat soft.  I could keep turning the round nut and it seemed to be pulling the pitman through the nut (towards the adjustment end).  That didn't seem correct so I decided to approach the experience of the forum again.  I have the unit held in the center position but it seems like it would have to be moving some for the pitman to move axially.  Is the definition of " the stop" that point where the pitman doesn't move?  Do you guess I don't have the unit fully secure in that position?

And what about the initial position of the adjusting screw?  It would help to understand what is happening inside the unit (for me).  Any further advice or elaboration would be greatly appreciated.

Harry

[Harry]

Interesting.  I posted a foloow-on post yesterday and it is visible in the "Topic Summary" box displayed below for this Reply.  But - it isn't visible when normally reviewing the entire post.  Perhaps I am doing something wrong?  Regardless, I will post again since it appears that the prior post didn't go through.

I was finally getting back around to the PS Box last evening, setting pre-loads in accordance with the hand drawn instructions from this post.  (Very nice by the way.)  The front bearing seemed to go well.  I couldn't get comfortable with the round nut and hex nut on the pitman shaft, though.  The instructions say to "fit the round nut to it's stop".  I found that the stop seemed somewhat soft.  I could keep turning the round nut and it seemed to be pulling the pitman through the nut (towards the adjustment end).  That didn't seem correct so I decided to approach the experience of the forum again.  I have the unit held in the center position but it seems like it would have to be moving some for the pitman to move axially.  Is the definition of " the stop" that point where the pitman doesn't move?  Do you guess I don't have the unit fully secure in that position?

And what about the initial position of the adjusting screw?  It would help to understand what is happening inside the unit (for me).  Any further advice or elaboration would be greatly appreciated.

Harry

[jeffc280sl]

Hi Harry,

Do you have a parts breakdown view of the pump?  I'm sure its posted here or in the tech manual.  You can see how it works if you look at the digram.  The adjustment screw is spring loaded and it helps keep a small load on a half globe fitting that nests snuggly in another fitting.  Sorry for the vague description.  This helps remove any slack or play in the box.

[rutger kohler]

Hi Harry, first of all I should have credited Dave H with all the on line help on the power steering box. I also got some printed info from the guy I got my complete power steering outfit from.  The information is very comprehensive but unfortunately the copying didn't come out very well at all.  Because of this the only page that I can pass on is attached now.  In it you can see the spring loaded shaft you are preloading puts axial pressure on the output shaft.  Hope this helps.  The attachment is a PDF type which I find is the clearest. I too had trouble getting my pre-load down to 26 ftpounds. To be honest it is probably more like 30- 32 ftpounds but I am reliably told this is fine.

[rutger kohler]

Try expanding the diagram to 50% on Adobe reader.  The area you want to look at is parts 21 -28.