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Hydraulic pump and self leveling valve

A

Alastair

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Jan 13, 2006
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17
Hi,
I'm wondering if anyone can give me some definitive advice. I've read a lot of threads about the self leveling on 124 estate models and understand how the system works. Currently I think I need to renovate the self leveling valve. Does anyone know where from and how much I could expect to pay? Also is it a tricky job? For instance can it be done with the unit in place and will I have to disturb any of the pipes.
Secondly I'm loosing fluid from the hydraulic pump. The steering is not effected but fluid drains straight out from underneath when the tank is filled or the hose is squeezed. All connections to the unit are in good condition but is there a bleed valve or something underneath that might be damaged? If I need to is it a tricky job to overhaul this unit or should I just get a reconditioned one and if so where from.
Thanks for any advice! Cheers.
Alastair
 
regarding the self levelling valve why do you think you need to overhaul it?

there aren't that many things that can go wrong with it, normally, the fail is that when you park the car the rear "sinks" like an old Citroen.

There is an overhaul kit available from MB (although they will swear blind it doesn't exist :() which is basically a spring, a ball bearing and a couple of seals. Replacing the valve is no big job, it's just behind the drivers side rear wheel and attaches to the anti roll bar.

The more likely failure on a W124 estate is the rear spheres

What are your symptoms?

Andy
 
yes malcolm, but he's already said that is from the pump.

now, have a look at your diagrams and you'll find that is at the front of the car not the back where the self levelling valve is.

Also, as the system is self bleeding, even if the pump leaks the suspension will still work as it is designed to in terms of damping and levelling it will just lose fluid.

The smart cookie would also have pointed out that the hydraulic suspension reservoir has nothing to do with the steering nor does the steering pump.

The suspension reservoir is inside the passenger side wing, the pump attached to the front of the engine, it's actual position depending on engine size/number, the steering pump is entirely different

but of course you knew all of that hence your oh so helpful post :D

Andy
 
Last edited:
andy_k said:
yes malcolm, but he's already said that is from the pump.

now, have a look at your diagrams and you'll find that is at the front of the car not the back where the self levelling valve is.

Also, as the system is self bleeding, even if the pump leaks the suspension will still work as it is designed to in terms of damping and levelling it will just lose fluid.

The smart cookie would also have pointed out that the hydraulic suspension reservoir has nothing to do with the suspension nor does the steering pump.

The suspension reservoir is inside the passenger side wing, the pump attached to the front of the engine, it's actual position depending on engine size/number, the steering pump is entirely different

but of course you knew all of that hence your oh so helpful post :D

Andy
Click to expand...

No my post was not helpful, I know nothing about the system and I have never posted on this subject ever in my life :D:D:D
 
fredfloggle said:
Increased the post count by two though.
Click to expand...

Nothing to do with post count as you well know.

I dont see much point in Andy answering himself if the point that the OP made himself "I put fluid in and it runs straight out" was ignored. It is a great hydraulic system that runs on no oil in it.:D
 
The point I was making is that I suspect the original poster is mistaking the steering pump for the suspension pump. Or maybe he has two separate issues, one with the steering and one with the suspension

As far as I know, there is no pipe to squeeze on the suspension system - it's a solid metal one

Which is why I asked for a bit more information rather than jumping to conclusions that would probably be wrong

Andy
 
Alastair said:
Hi,
I'm wondering if anyone can give me some definitive advice. I've read a lot of threads about the self leveling on 124 estate models and understand how the system works. Currently I think I need to renovate the self leveling valve. Does anyone know where from and how much I could expect to pay? Also is it a tricky job? For instance can it be done with the unit in place and will I have to disturb any of the pipes.
Secondly I'm loosing fluid from the hydraulic pump. The steering is not effected but fluid drains straight out from underneath when the tank is filled or the hose is squeezed. All connections to the unit are in good condition but is there a bleed valve or something underneath that might be damaged? If I need to is it a tricky job to overhaul this unit or should I just get a reconditioned one and if so where from.
Thanks for any advice! Cheers.
Alastair
Click to expand...

What model is it?

I ask because some like a 300TE have a pump that is built into the PAS pump, and others like the 230TE have a cam driven pump on the front of the engine.
 
Hi,
Thanks for all of your replies. Firstly I suspect the self leveling valve my be shot, or at least leaking as last year the linkage broke. This made the back of the car raise up alarmingly and become incredibly bouncy (try telling that to the wife!). I had no idea what was wrong 'till later, but at the time fluid was dripping out of the self leveling valve. I kind of assume that this might be blown seals or something, given the pressure the system can operate out and that it wasn't cutting out. I am now thinking that if a reconditioning kit involves a spring and ball bearing that this is some sort of safety valve set up so may be seals won't have blown?
As regards the hydraulic pump I have a hose going from the reservoir tank to the pump unit. This may have been used to replace a length of pipe. The car is a 280 TE from 1993 and I believe the hydraulic pump is below the steering pump. At least the steering fluid reservoir is on top of the bit that the suspension fluid is leaking out from.
Given the nature of this pump unit is it a tricky one to recondition, is it a tricky job and any idea on where could a get one and how much? Cheers guys!
Alastair
 
Alastair

Yes you have the tandem pressure pump which is a combination power steering and level control pump.

If there is ever an overload on the level control side of the pump, a shear pin will shear and allow the power steering pump to continue operating.
 
Thanks, the system is likely to have been overloaded due to the self leveling linkage having broken. Would this shear pin cause a leek or is it internal and within the tandem unit? Essentially is it repairable or do I need to remove and recondition? Also any idea where would I find a diagram of the unit?
Thanks for the info!
Alastair
 
Alastair said:
Thanks, the system is likely to have been overloaded due to the self leveling linkage having broken. Would this shear pin cause a leek or is it internal and within the tandem unit? Essentially is it repairable or do I need to remove and recondition? Also any idea where would I find a diagram of the unit?
Thanks for the info!
Alastair
Click to expand...

http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=M&cat=505&SID=13&SGR=030&SGN=01
 
Thanks for the link, I can understand stuff better when I can see it! Any idea about if it can be repaired or am I looking at replacing the unit?
Cheers!
Alastair
 
Alastair said:
Thanks for the link, I can understand stuff better when I can see it! Any idea about if it can be repaired or am I looking at replacing the unit?
Cheers!
Alastair
Click to expand...

I don't see why it can't be rebuild, but I suppose it depends what's wrong with it.

If it does prove to be mission impossible I've got a new one going cheap...
 
If the pump leaks when the feed pipe is squeezed then there must be a hole somewhere in the pump body of feed pipe.

The height corrector having a paddy can't damage the pump as there is a pressure relief valve.
 
television said:
Nothing to do with post count as you well know.

I dont see much point in Andy answering himself if the point that the OP made himself "I put fluid in and it runs straight out" was ignored. It is a great hydraulic system that runs on no oil in it.:D
Click to expand...

No I don't, that's why I said it. Hydraulic systems can run on water if we are going to be pedantic.
 
Thanks again all for posting. I've had a good look and fluid appears to leek out from behind the pulley wheel. This makes me think, according to the information on the diagram supplied by Nick Mercedes that I need a recon pump or a gasket/seal kit. Has anyone done either of these jobs before and is it awkward? I'd have to drain the system, disconnect four hoses and a couple of cables, remove the pulley wheel, remove and replace the unit.
 
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