Power Steering box leak: pitman shaft seal

[M104-AMG]

Got a massive leak on the pitman shaft of the power steering box.

What are the best options:

1) re-seal just the shaft leak with the steering box in-place;
2) remove steering box and re-seal EVERYTHING;
3) find a rebuilt replacement steering box (are all W124's interchangeable, with ratios (e.g., Sportline, 500E) being only different ?

BTW: anyone have a steering box for sale . . .

Thanks,
neil

 

[nocfn]

Restore the shaft seal leaving it installed. There is a HOW-TO on this and is generally a simple deal. I have done it myself using the HOW-TO.

 

[gsxr]

If it's only the pitman shaft, re-seal per the HOW-TO, with Genuine MB seals only.

If the input seal is leaking, buy a complete re-sealed box from C&M Hydraulics.

V8 boxes are different than non-V8 on the 124. Don't mix & match, it won't work.

 

[altezza]

2) remove steering box and re-seal EVERYTHING

 

[gsxr]

2) remove steering box and re-seal EVERYTHING

Disassembling the entire steering box and re-assembling it (without screwing it up) is not a simple DIY job.

 

[TerryA]

It’s been a while, I paid a a Tech I know a couple hundred bucks to rebuild my 500SL steering box in his garage. I R&R it myself.

 

[altezza]

Disassembling the entire steering box and re-assembling it (without screwing it up) is not a simple DIY job.

I have done it twice.

 

[gsxr]

I have done it twice.

Congrats! Glad you had 2 successful rebuilds.

I still don't recommend this for 99% of DIY'ers. I did a lot of research and decided there is too much risk involved, along with trying to set the final rotational torque. There are extremely few, if any, "HOW TO" articles discussing this job. In USA, a "rebuilt" steering box is ~$400 USD with exchange and in general it isn't worth the risk. If that changes in the future (either NLA or extreme price increase), that would be a different discussion.

 

[altezza]

Using Dial Torque Wrench, adjust to 1.2nm near center.

 

[M104-AMG]

Found a NOS kit made in Germany (8/95) by DPH. Has the "double-lip" unlike some other seals. However, should I be suspect if no MB logo or MB
pn#s ?

neil

 

[gsxr]

I know the OE seal kit is NLA, but you can buy the individual seals from the dealer, right? The output shaft (Pitman arm) is the main one you are concerned about. OE seals have the MB Star logo and part numbers on it.

Just checked - OE MB shaft seal is under $5 from discount dealers... still available.

 

[M104-AMG]

Thanks Dave!

So just item numbers #92 and #86, correct ?

neil

 

[gsxr]

92, 95, 86 for the V8 box, for the output shaft re-seal.

Details & photos in thread below:

HOW-TO: Re-sealing the power steering gearbox output shaft at Pitman arm | "HOW-TO" Tutorial Articles

The power steering system is the source of many fluid leaks on the 500E/E500 (and its baby brother, the 400E/E420). Along with the three rubber hoses for the fluid lines to & from the pump, the gearbox itself can also leak. If there is visible wetness at the gearbox, first clean it off with carb...

www.500eboard.co

 

[M104-AMG]

Well look what I found buried in a box . . .

 

[gsxr]

Well look what I found buried in a box . . .

Nice find! EPC says that kit should work for the 6-cyl box, although some parts (like the output/Pitman shaft seal) are the same on the V8 box.

 

[M104-AMG]

Nice find! EPC says that kit should work for the 6-cyl box, although some parts (like the output/Pitman shaft seal) are the same on the V8 box.

Now to decide if I want to just replace that seal, or R&R for a C&M . . .

neil

 

[TimL]

If it's only the pitman shaft, re-seal per the HOW-TO, with Genuine MB seals only.

If the input seal is leaking, buy a complete re-sealed box from C&M Hydraulics.

V8 boxes are different than non-V8 on the 124. Don't mix & match, it won't work.

C&M rocks! I bought a refurbished tandem pump from them in exchange for the my leaking tandem pump and they are friendly, fast and exacting in what they do.

 

[nocfn]

I agree. CM does just about every pump no matter where you get it in the states.

 

[dionphaneuf]

@gsxr is the 500E box much more complicated than that on the w126? I've considered doing that job on my 86 SEC as I know it's leaking, although perhaps doing an abridged version as is done here is possible if only certain seals are leaking. When I first looked there were several DIYs available such as this one and this one that seemed tedious but not insurmountable and I know @jhodg5ck mentioned the same, but your reluctance gives me pause.

 

[gerryvz]

The two chassis' steering boxes are the same design.

HOW-TO on resealing the lower part of the E500E box is here: HOW-TO: Removing and re-sealing ZF tandem pump (SLS and power steering) | "HOW-TO" Tutorial Articles

 

[gsxr]

@gsxr is the 500E box much more complicated than that on the w126? Ive considered doing that job on my 86 SEC as I know its leaking, although perhaps doing an abridged version as is done here is possible if only certain seals are leaking. When I first looked there were several DIYs available such as this one and this one that seemed tedious but not insurmountable and I know @jhodg5ck mentioned the same, but your reluctance gives me pause.

IMO the main difference is that you can't replace the E500E input shaft seal without total box disassembly. This is not for the faint of heart. Early 124 boxes, through about 1989, can have the seal replaced externally IIRC. The 126 box may be similar to the early 124, I'm not certain.

124 chassis steering boxes, IMO, almost never need a "rebuild". Typically they leak at the output shaft seal, and that is DIY fixable. In addition to the link Gerry posted above, also see the 2 links below with a lot of detailed info. If a late 124 box is leaking at the input shaft, then just get an exchange gearbox from C&M, or send yours to C&M if you have time to spare. I'd recommend the latter if possible, along with sending C&M new OE/Genuine input/output shaft seals, which are better quality than the aftermarket seals they normally use. Worth the extra $10.

FYI - HOW-TO: Replacing steering gearbox on 124.034/.036 chassis | "HOW-TO" Tutorial Articles

This is not a step-by-step procedure or pictorial (sorry). It's some observations and tips to complement the FSM (Factory Service Manual) procedure, job 46-3400, see attached PDF file. This journey is not as fun as the travel brochure claims. Plan on 4-6 hours if everything goes smoothly, if you...

www.500eboard.co

HOW-TO: Re-sealing the power steering gearbox output shaft at Pitman arm | "HOW-TO" Tutorial Articles

The power steering system is the source of many fluid leaks on the 500E/E500 (and its baby brother, the 400E/E420). Along with the three rubber hoses for the fluid lines to & from the pump, the gearbox itself can also leak. If there is visible wetness at the gearbox, first clean it off with carb...

www.500eboard.co