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Discussion Starter #1
Hey guys

I have replaced the spheres and put in a used self level valve. However, the ride height is still not adjustable. Nor does the car raise back up to normal with added weight. Any troubleshooting ideas here?

Thanks
 

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What do you mean the ride height is not adjustable....the little turnbuckle has no effect on ride height? Can you move the rear up & down with the SLS valve lever by hand? Maybe the bracket up on the sway bar is loose or out of the adjustment range. Is the ride still jerky or smooth?

It can take over 300lbs to make the rear self-level.

Kevin
 

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Discussion Starter #3
Moving the valve leveler has no effect on the ride height.

The ride is smooth. Definite improvement after replacing the valve.
 

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If the car is idling, you've disconnected the SLS valve turnbuckle and the control lever does not move the car up & down slowly....you've got a problem. Most likely it's your pump itself.....needs to be rebuilt. Usually when you have a bad SLS valve it just leaks hydraulic oil, but maybe there's a problem there too since it's used.

But if the pump is not putting out enough pressure, your SLS system will not work....ergo, moving the SLS lever has no effect.

How and why did you determine your other SLS valve was bad?

Kevin
 

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Discussion Starter #5
If the car is idling, you've disconnected the SLS valve turnbuckle and the control lever does not move the car up & down slowly....you've got a problem. Most likely it's your pump itself.....needs to be rebuilt. Usually when you have a bad SLS valve it just leaks hydraulic oil, but maybe there's a problem there too since it's used.

But if the pump is not putting out enough pressure, your SLS system will not work....ergo, moving the SLS lever has no effect.

How and why did you determine your other SLS valve was bad?

Kevin
My mechanic suspected it was the culprit as it often is. I am not sure if he looked into the pump or not. I'll ask him. Thanks!
 

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There is a rebuild kit for the sls on a s123. Not sure about s124.

Yeah. If it doesnt move at all when you move the lever, with weight in the back, there is either no oil or a problem with the pump.
 

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You may need to bleed the system, if you have no already done so.
I use plastic containers, as big as will fit in the back and fill them with a garden hose.
Then rev to 2500rpm for 90 seconds, job done.
 

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be sure to ONLY use the correct hydraulic fluid in the reservoir.... its not ATF, its not tractor juice, or anything else, its a very specific mercedes hydraulic oil. I think its made by Pentosin, but the real mercedes stuff is not overly expensive and easier to get than any of the substitutes so I stick with it. same stuff is used in Mercedes power converible tops, btw.
 

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There is a bleeder on top of the SLS valve; its purpose is to bleed the system at that point. Also, cracking the hoses to the rams if necessary. I don't think however, this is his issue as driving the car around self-bleeds the SLS system to some extent as well. He has no rear movement working the SLS lever up and down. Even with some air in the system he would have movement, albeit slow.

I'm betting it's his pump. The proper hydraulic oil is sold as a Febi product....it is Pentosin supposedly. Febi relables their products sold, as they don't manufacture anything. Auto Zone here has two types of Pentosin, with one being the correct fluid for the MB SLS/4Matic system. However, it's almost $30 for a qt which is obscene....obviously, they don't sell a lot of it...lol.

Kevin
 

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There is a rebuild kit for the sls on a s123. Not sure about s124.

Yeah. If it doesnt move at all when you move the lever, with weight in the back, there is either no oil or a problem with the pump.
Yeah, no one was sure @peachparts if the 123 SLS O-ring kit offered would even work on a 124 SLS valve. I've never been inside one, but I gotta believe it's just a simple hydraulic switching valve sealed with O-rings. Unless some orifice plugs with grit internally or the O-rings flatten with age/use, I don't think there is much inside to fail. Maybe the salt belt can shorten their lives.

I gotta figure his mechanic put oil in the system at the very least...lol.

Kevin
 

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Discussion Starter #11
Yeah, no one was sure @peachparts if the 123 SLS O-ring kit offered would even work on a 124 SLS valve. I've never been inside one, but I gotta believe it's just a simple hydraulic switching valve sealed with O-rings. Unless some orifice plugs with grit internally or the O-rings flatten with age/use, I don't think there is much inside to fail. Maybe the salt belt can shorten their lives.

I gotta figure his mechanic put oil in the system at the very least...lol.

Kevin
He's a Mercedes specialist so I think he knows, but I will double check with him tomorrow.
 

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Discussion Starter #12
He uses the correct fluid. He tested the pump and it's functioning properly. There's not much else to check. So I ordered another valve and trying to return the used valve I purchased on eBay. I'll keep you posted! Thanks for the tips everyone.
 

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I can't think of what else it could be....unless one of those ganglia of lines that goes to the SLS valve is crimped or plugged.

Was it ever working since you owned the vehicle or are you trying to make it work again?

Kevin
 
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