Steering Box Removal

[kampala]

This steering issue is on a LHD, later 250sl with power steering.  Would appreciate some advice. 

This car has been driven somewhat regularly for the past few months and the power steering has been working very nicely -- no slop, no moaning, smooth and accurate steering.

Today, without warning, upon start up, the steering lost all power and became incredibly tight.   The reservoir started spitting up and the fluid inside was foamy.   I now see that the steering box is leaking from underneath (several drops in a minute) and is dry on top.  I assume this leak is allowing air in and hence the spitting and foam at the reservoir?

After searching on this forum, I have found lots of information on how to take the steering box apart and rebuild/reseal and have determined that a full dismantle and reseal is above my skill level and risk appetite. 

So here are my questions:

1. Does it make sense to leave the steering box in place, and just replace the lower seals from underneath?  I have read conflicting information if this is possible.  In addition, even if possible, is it a good idea and do such partial seal replacements work or is a complete dismantle and reseal the only real option?

2. If I decide to just replace the entire steering box with a fully rebuilt unit, how difficult is it to remove the old unit and replace with a rebuilt unit?  Can this be done without a lift?  How difficult is it to line up the gear box?  Any special tools needed?

Would appreciate any advice as the search results I've found mainly discuss how to re-seal/rebuild and not how to remove and replace.

Thanks.

[Mike K]

My neighbour has a W111 coupe and had the same ongoing issue, he kept opening up the box and replacing the lower seals with his own "home-made seals".
I eventually convinced him to order the proper seals (they're the same for W108 to W113) from SLS, which I did for him as he can't use a computer:
http://www.sls-hh-shop.de/en/230-280SL-W113/46-Steering/46-d-Steering-Gearbox-Fluid-Pump/Gasket-kit-pwr-steerg-div-108-113-Gasket-kit-pwr-steerg-div-108-113.html

Without removing the box, he replaced the lower seals and problem is solved. I'll speak with him today and find out the procedure and details and get back to you.

Best,

Mike

[Mike K]

I've spoken with my neighbour, he says it's best if you call him and he'll explain what to do. I've sent you a PM.

Best,

Mike

[tel76]

Hello OZ,
There is only one way to satisfactorily do this job and that is get a replacement box from a reputable overhaul company (the car deserves it) if you did change the lower seal you still have many more 'O' rings and seals that are past there best.
The replacement box can be fitted by yourself but it is a PITA job to do.

[ctaylor738]

Concur.  It's an awful job.  The box has a bulge that fits in an indentation in the frame. I have found it impossible to maneuver the box into position and engage the splines in the coupler at the same time.  On the two that I've replaced, I dismantled the dash and pulled the steering column up, put the new box in and moved the column/coupler down to engage the splines.

As to special tools, you need a suitable puller to get the Pittman arm off the box.  This is easier to do on the bench, so you may wish to disconnect the drag link and tie rod, in which case you will need a "spreader."

You will need a suitable bolt with the end filed to a point to lock the box in the straight-ahead position for installation.

I had a third opportunity to replace a box.  I declined.  The owner took the car and a rebuilt box to a dealer shop and they installed it for $400.

[kampala]

Mike, Eric & Chuck,

Very much appreciate the help and your clear opinions.  Your responses are very helpful.   Got some decisions to make.   


Thanks

[scoot]

I replaced the steering coupling (coupler?) bushings on my car, it was a pain.  It involves disconnecting the steering box from the steering shaft and then later sliding it back on.  That's difficult but I could do it.  I don't know how much more work it is to actually get the box out since I didn't need to do that.  But if you are taking the box out, I would replace the bushings in the coupling at the same time (unless it's been done recently) since it's easy access then.

[George Des]

Chuck's advice on removing the steering column is the only way to go on this. Yes, it is a pain to remove the tach and speedometer, but it is a lot less painful than trying to hold that heavy box in place while trying to maneuver it into that indentation and align the splines. I've done it both ways and if I should ever need to do it again, it will only be by using Chuck's method of R&R.

George

[scoot]

Chuck's advice on removing the steering column is the only way to go on this. Yes, it is a pain to remove the tach and speedometer, but it is a lot less painful than trying to hold that heavy box in place while trying to maneuver it into that indentation and align the splines. I've done it both ways and if I should ever need to do it again, it will only be by using Chuck's method of R&R.

I guess when I did it I found it to be difficult but not that difficult.  It was easier on a fintail because of more room.  I didn't find getting the splines lined up to be that much of a problem. 

[ja17]

I've done it both ways. It does take a knack to just remove just the box. In any case, unbolting the cover around the steering column at the fire wall is important. It can be slid up the column so access to the coupling bolts can be had. I carefully mark everything before I disconnect. Be aware that the slash mark on the steering column at the steering wheel, may not have gotten set-up correctly during previous repairs. Check it first. 

[kampala]

All,

Thanks so much for the precise details, intricacies, cautions and words of mechanical wisdom you have all provided.   Could not ask for more!  

Mike, I did speak to your neighbor and he was so gracious with his details and even offered to help fix it in his home garage.  Please relay my appreciation.

Well, after looking at the steering gear-box very carefully I felt that the main leak was the large seal underneath, but there were other areas that had very slight evidence of weeping --- it made most sense to have the unit fully rebuilt.

Heeding your advice of caution, I decided that removal and reinstall of the steering gear-box was not a job for me but rather for someone with specific experience with these boxes.  Since I did not want to damage anything by driving the car too far with fluid spewing, I took the car only 3km to a mechanic in his 70's who has been working on 1960's Mercedes cars for over 50 years.  After discussing how the steering was prior to this failure (no slop, smooth, accurate), we decided to have my steering gear-box rebuilt rather than getting an exchange unit.  

The mechanic and his helper pulled the steering box, had it rebuilt locally and reinstalled it without issue.  I really wanted to watch the install but had to be at work.   The car now drives very nice again and my panic over aligning the spline connection is no more.

I'm very glad I posed the question on our site and very much appreciate your responses.   What a great bunch of members!