Self Levelling Suspension on 1986 560SEC
 

Hi Guys...I have rebuilt and replaced the Hydraulic Pump four times in the last year.
The hydraulic pump is now once more leaking hydraulic fluid into the engine sump (not a good look) !!
Question is :if the rear suspension level is set too high can/will the pressure become excessive and cause the leak?
I am looking for a reason other than the twin-lipped seal for the leak.

Thank you one and all

I will probably be of no help here as I am new to the self leveling system on my 1990 300TE.

I do however know just a bit about hyraulics. I don't have to tell you how much pressure is generated...so suffice to say...the seals and sealing surfaces must be perfect, as well as the oil must be spotless. The metal shafts that the seals ride on must be micro polished. The seals you are using...though they may be rated for the job, still might not be the BEST ones for the job.

My suggestion...when you yank this pump again...send the seals to a seal house. Explain exactly what these seals do, how it is used, the oil used, the whole thing. The inhouse tech should be able to recommend the best seal for this job. I would also take the mating surface to a machine shop, expaining to them what is going on..and have them polish the surfaces. Completely drain your lines and inspect the oil. If the oil has ANY contaminants whatsoever, it could be hoses internally detiorating. The debris from this can cause leaking very quickly.

Buying a new OEM pump should give you no problems. If it is remfg or off brand...you have no idea if it is just bad workmanship. Better to either go brand spanking MB new...or rebuild it yourself with quality.