posted in the SL55 forum a few days ago and didn't get any response, so I'm looking to see if anyone knows how to fix this in the regular 230 forum

I just recently did the following on my sl55:

replaced front valve block
replaced front valve block accumulator
rebuilt rear valve block
replaced rear valve block accumulator
replaced pulsation dampener
replaced return line accumulator/dampener
replaced hose that goes from front valve block to left strut
replaced hose that goes from front valve block to right strut
replaced hose that goes from pump to pulsation dampener/pressure limiting valve

here's my problem, when I start the car pressure builds to 250 bar. Pressure is supposed to be regulated to 200 bar. The high pressure in the system is causing fluid to just pour our of the pressure limiting valve. I replaced the pressure limiting valve thinking it might be the problem, but the system still remained at 250 bar and after about 10 minutes at idle the new pressure relief valve starting pouring out fluid.

The hose that goes from the pump to the pulsation dampener originally had some sort of metal inside of the first flexible rubber hose section, very similar to a power steering line that has it dampen noise as a flow restrictor. When I replaced that hose I had one built with flare nut ends and as a result it does not have the piece of metal inside of the first rubber hose.

I'm thinking either the new hose is the reason the pressure is too high and I keep blowing pressure relief valves (not sure if they are trashed now or not) or maybe the suction restrictor on the pump isn't working correctly (at some point in the past someone had replaced the pump and for some reason the wiring going to the suction restrictor on the pump was cut and then spliced back together). Anyone have any clue on this?

The pressure relief valve is leaking out of the bolt next to the pressure sensor. Originally it had what looks like a cap in it in the middle. When it started leaking this cap blew off and there is an allen wrench head underneath now showing. Do I need the cap thing back on to get the thing to stop leaking? (I have no clue where it is btw) Do I need to turn the allen wrench head at all and if so which direction and how much?

I am totally lost here and super frustrated as I have spent an enormous amount of time and money on this suspension refresh project.

 

Any chance when you put in the new line to the pulsation dampener it got kinked or squeezed somehow and now restricts flow? You wrote me once saying it is a tough one to install.

moretech

 

Hi, Did you manage to fix the issue? I got the same issue, the pressure is 248Bar and the pressure relief valve is leaking.
Venom

 

The problem was that a return line & pressure line got mixed when putting the front valve block back on. The hoses look like they should hook up one way but they don’t. The pump then puts pressure in the return circuit and starts blowing hoses & the pressure relief valve.

 

Great info, I just had the Front Valve block rebuilt recently. My technician has no idea why did it happen. I will ask my technician to trace those hoses. Thank you so much for your information.

 

My technician has swapped the pressure line and return line. However, the pressure relief valve is still seeping. Any reset procedure is required to perform after the pressure relief valve is opened ? I haven’t asked them to check the pressure level.



Before swapping

 

Here’s how the lines on my 2005 SL65 were configured from the factory.

 

The pressure regulating valve is meant to divert pressure INTERNALLY through the return. Swapping those two lines dead ends the return from the pressure valve and the rear valve by putting it on the wrong side of the return regulator. I think there is some sort of rupture disk in the pressure regulator that will release oil in this case. It is not part of the valve function, there is no reset, you need to replace the valve.