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Old 10-17-2002, 05:20 AM
Registered User
Join Date: Oct 2002
Location: Vanersborg, Sweden
Posts: 99
Unhappy Self leveling system bad leakage

Hello friendes,

Im brand new to this forum so I hope You excuse me if this question has been posted numerous times. Ive just bought a 1984 500 SEL with the self-leveling system. For some reason there is a leak in the system. The hydraulic fluid cannister was empty when I bought the car but everything seemed to be functioning OK so I bought the car.

When I checked the rear suspension by pushing down hard on it and releasing it swings up - down- up instead of just up. But driving reveals no bounciness or hard ride. The rear also seem to be maybe 1 inch lower than the front but I wouldnt say its low (I would prefer the front to be 1 inch lower instead).

Now to my problem - The other day I filled 3 liters of hydraulic oil in the reservoir and after driving a bit it seemed as if the rear was a little more stable and maybe a little bit higher than before.
So I was a happy camper.

The day after I rechecked the oil in the reservoir and it was empty

Ive been under the car and have not found the leakage (the weather is wet here now so I might have missed it). I looked at the engine oil dip stick and the oil level have risen.

Is this possible can the pump be leaking oil into the engine

Im thinking now that maybe my best option is to remove the self leveling system and go for new "straight" shocks and springs in the rear?

I understand from the earlier threads on this subject that rebuilding/ installing a new pump would be in order as well as installing new nitro-bladders but this would cost quite dearly. To go for "straight" shocks and springs is much cheaper.

Before I run of on any crazy tasks I submit to the collective visdom of this list for advise on how to troubleshoot the system more in detail as well as input from others that maybe already have rebuilt their cars in the same fashion as Im considering.

Please give me all the advise You can.

Many thanks,

Mikael Westerberg
1984 500 SEL
Vanersborg, Sweden
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Old 10-17-2002, 11:14 AM
MikeTangas's Avatar
Senior Member
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
The leveling pump is mounted to the block, just under and left of the distributor. I expect it is possible the pump could be leaking internally into the crankcase. If that is the problem, you need to replace or reseal the pump and get the motor oil changed. Hydraulic oil is much, much thinner than motor oil.

You say the oil level came up in the engine, did it come up about 2-3 liters? If the level came up, it is very likely the pump is leaking into the crankcase.
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon least its a diesel

Non illegitemae carborundum.
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Old 10-17-2002, 04:41 PM
Registered User
Join Date: Oct 2002
Location: Vanersborg, Sweden
Posts: 99
Ive been under the car some more today. Im not sure about the engine oil level rising so I have to check that out some more (making sure I was on level ground etc), before jumping to any conclusions about the leveling pump leaking into the engine. though I havent ruled that one out yet

One thing I noticed, however, is that the steering gear housing is really wet with oil. I dont see the oil level in the power steering pump falling so could that be the hydraulic oil from the rear leveling system return line is routed there such that it leaks on the steering gear?

Can anyone give me more info on how the feed and return line is routed such that I can nail this one down.

Please please,

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Old 03-18-2003, 11:00 AM
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Join Date: Jan 2003
Posts: 211
Mikael - 1985 300 TD wagon - I have a leak that is in the return line (one that goes back up to top of reservoir) - this line goes from top of res down under engine under oil pan back up passenger side fender under car on passenger side - with pressure line that comes off bottom of reservoir, around front of engine near radiator around and down pass fender. I knoa there is a leak because - it dumps right there at "saddle" part of frame under oil pan. Will have to splice in new tubing. Have yous fixed your problem yet - I saw that this post was in 02?
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Old 03-18-2003, 01:36 PM
Registered User
Join Date: Oct 2002
Location: Vanersborg, Sweden
Posts: 99
Hi (S)martin?

Yup, I confirmed that the leakage was between the hydraulic pump and the engine. I had to flush the engine and change the filter and oil after that. I also tried to renovate the pump but the bolts were completely frozen. After I got tired of trying to loosen them I replaced the rear shocks with standard ones.

That was a good fix. The ride was much imroved and the car handled better. The reat end was still to low though.

I drove with that for about 3 months and after that I also changed the rear springs for Standard springs i.e not designed for the hydraulics.

That was a big improvement. Not only is the stance of the car back to normal but the "wandering" at speed is much improved. Its now much better to drive. Probably because the earlier sagging rear end changed the steering angles a bit.

Good luck/ Mikael
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