Author Topic: Rear axle SLS valve leaking  (Read 226 times)

BCK1963

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Rear axle SLS valve leaking
« on: 02 May 2021, 09:19 AM »
Hello,

the rear SLS actuator of my  car is leaking a bit and I think ahead of how to best get that fixed. The rubber protector is done and I have new replacements. So some questions into the audience concerning that topic.
It looks to me like the front and rear units are identical and even interchangeable with W126 parts. The W116 parts calalogue lists only the W126 part 126 320 0658. Correct?

Has anybody ever worked on that? What are typical causes for leakages on this part? Its interior looks more complicated that the valve unit in the engine bay on top of the fluid reservoir. Can that be done without specialized tools?

Unfortunately I don't have a lift where I could leave the car resting on for a longer time. In my wildest dreams I think of swapping front and rear units and be able to work on the leaking one during the next winter with the car on blocks. Would that make sense?

   Thanks ahead
Bernd

1976 Merc 6.9  since 2013
1974 Caddy CdV   since 1992  (for sale)

daantjie

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Re: Rear axle SLS valve leaking
« Reply #1 on: 02 May 2021, 12:53 PM »
Bernd, yes the front and rear valve is the same and also it is the same number and part shared with the W126, both Gen 1 and Gen 2 systems.

Best option is to send them to Martin Werminghausen for rebuild.  Member "tcj" - Thomas can put you in contact with him as well.  Martin is based in the US - Massachusetts I believe and I think Thomas is in Germany.

Mostly I have found it is the shaft seal which leaks, and usually the rear one goes first.  Then you get hydro oil leaking out, and this then eats the rubber boot over time.  Changing the boot only will not help the leak situation and you may as well go the full rebuild route then.

Cheers
Daniel
1977 450 SEL 6.9 - Astralsilber

nathan

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Re: Rear axle SLS valve leaking
« Reply #2 on: 02 May 2021, 04:34 PM »
If cost is an issue, perhaps try and get one off another car?
I swapped mine out of the 123 a few months ago, a short video how I removed it which was pretty easy
https://www.youtube.com/watch?v=LCQEXRdwjbY&t=135s
6.9 79 #6436
6.9 79 #6290
6.9 79 #6181
6.9 78 #4764
6.9 77 #3096
6.9 76 #1741
6.9 76 #0902
6.9 75 #0018

BCK1963

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Re: Rear axle SLS valve leaking
« Reply #3 on: 02 May 2021, 10:58 PM »
Thanks Daniel, Nathan,

maintaining this car at a more than minimum level is always about costs, I guess.
I tried to find a cheap valve for diy trying but for the prices asked I can have mine revised.
Thomas / tcj is located in Germany and I know him by phone. He is one of the guys who is specialized in repairing HPF parts.
But, as I said, I don't have a lift or place available where I could leave the car for an extended time with the rear valve removed.
So I probably have to get a revised one and send mine back as core.

Just in case:
Are the shaft seals easy to remove and available? The seals in the unit above the reservoir are only for specialists.

    cheers

Bernd

1976 Merc 6.9  since 2013
1974 Caddy CdV   since 1992  (for sale)

daantjie

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Re: Rear axle SLS valve leaking
« Reply #4 on: 03 May 2021, 08:51 AM »
To change the shaft seal you need to take the whole valve apart, so at that point you may as well have the valve checked and rebuilt.
Daniel
1977 450 SEL 6.9 - Astralsilber