Steering Gear Leak

I have a slight leak on the bottom seal of steering gear (400i). It lost about 1/8" in reservoir over about 5000 miles, so it is not big; it does make an oily mess below the gear. Since I replaced the unit with a used one some years ago I know it is a significant job to remove and replace. A few questions:
- How common is this seal leak?
- Has anyone replaced the lower seal?
- Do you have a part number / seal size?
- Can it be done with the gear in the car? (I doubt it!)
- Has anyone used one of the sealer products in the fluid? Which one? Did it work?
I've had mixed results on 'normal' cars with power rack and pinion. They usually hold for some time and then seal fails badly. This seal is a very low speed rotating shaft vs. a linear motion seal on a rack.

For now, I'm just going to top up fluid and clean under the unit but I want to plan ahead for next year's R&R.
Ken

 

Are you sure it is the seal? Reason I ask is those boxes have some internal O rings that are famous for leaking and it requires removal and disassembly to fix. I have done many. There is a small hole on the bottom of the housing and if oil is collecting there and running down that is the issue. Not saying it cant be the seal but I don't think I have ever seen that seal leak.

The seal kits used to be available from Mercedes Benz parts suppliers. I think it was the same as for 108 Benz's.

 

I'm not sure it's the seal; it could very well be one of the o-rings; all I see is the drips. I'll do a better clean up job and try to find the hole. Is it right on the bottom adjacent to the seal or a bit up the side of the unit, hopefully pointing way from engine?
Good tip on the MB part. I'll do a search.
Thanks much.
Ken

 

"There is a small hole on the bottom of the housing"

 

Rifledriver, what would it cost to have one of these rebuilt?

 

I was looking thru old emails on this subject and found this link to a 200+ page Bosch parts manual for these gear boxes. Apparently Bosch took over parts supply from ZF. Here is link: https://drive.google.com/file/d/0B3CL-Jr784cASVZ2S01Rc0U4MzhCaW9ZeV9abVVEaXltUFdr/view
Pelican Parts is working with me to identify the matching Mercedes parts.
Ken

 

The way Bosch is that is really not good news.

 

I purchased a few seal kits from T Rutlands part # 101112K back in 2015 they might still do them. I have not tried them yet to see if they are the correct seals.

Cheers,
Al

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