pumpedTSI

My passenger rear was sagging a few weeks ago so I removed the rear valve block, cleaned it, replaced the orings and reinstalled a spare valve block I had on the shelf. I also flushed the system, new fluid and a new 3 micron filter installed. There were no leaking or weeping hoses or struts, everything was bone dry.
Anyways, the rear still sagged so I reinstalled the original valve block that I had rebuilt but again no difference and no leaks. So the rear sags on one side with either of the rebuilt valve blocks and I have no leaks, clean fluid and new filter. The only thing I can think of is the strut itself bleeding down internally? I reused the same accumulator sphere but I figured if it was bad both sides would sag? Has anyone ever seen a strut with an internal leak? Can it be rebuilt like the valve block?
Does the accumulator hold the system pressure after the motor shuts off? Maybe its leaking internally or the bladder is ruptured?

GrepAwk

When the car is off, the valve block holds the pressure. There is one solenoid for left, and one for right.

The accumulator is not at fault for one side sagging.

If one side sags with the car off, then the lockout valve for that side is the problem, and it is not a problem with the shock at the wheel, unless fluid has leaked out of that shock.

pumpedTSI

Understood, but I have had 2 refurbished valve blocks installed.......strange they would BOTH have the same issue? I see no external leaks anywhere......I'm going to replace the accumulator anyways for the hell of it since I'm going in again......my system is spotless with new fluid, 3 micron filter and an inline magnetic filter at the reservoir.....no way its an internal strut bleed?

maw1124

Will the STAR diagnostic system notice a failing solenoid?

Also, Arnott rebuilds the shocks and should be able to confirm whether they fail internally.

maw

pumpedTSI

I understand what youre saying but I have had 2 refurbished valve blocks......both cant have the SAME failing or leaking solenoid? I have lost no fluid and all my hoses/shocks are bone dry hence my thought process on an internal shock bleed down...

Welwynnick

Statistically, the valve blocks are most likely to have the leak, but the truth remains that the struts have seals too. Heck, even passive dampers leak eventually. It's a rare occurrence for ABC struts, but this does sound like a leaky strut.


Nick

GrepAwk

PumpedTSI:
Why do you say it's not possible that BOTH valve blocks could ever have the same problem? Of course they could! Maybe both valve blocks that you have tried are indeed leaking at the right side. There are no garantees in life that two random solenoids won't both be bad. Maybe not likely, but it's possible.

Try this: swapping the lockout solenoids on the rear valve block you have in the car right now, left side with right side.
If the problem moves from right rear to your left rear, you have found....

Here's an even better test to save time: since both of your rear valve blocks in inventory seem to have a problem with the right rear, cannibalize the "good" left rear solenoid from your spare valve block, and insert into the right rear solenoid/valve position of the valve block on the car right now. Left and right use the same lockout component. So, now you should have two good (left) solenoids.

If after using two known good solenoids so you still have a problem, don't call me. I'm going to eat a cookie.

pumpedTSI

Grep,
sounds like a plan but a big coincidence. Help me out......what color are the solenoids for each side.....is the rear passenger side the yellow one? These are the smaller solenoids, correct?

GrepAwk

I would have to jack up my car and take belly pans off and...

Check Wellwynick's and HOAZ' posts and you might get a hint in pictures.

There are also some good ABC references elsewhere on interwebs.

Otherwise, get underneath the car and trace it on the installed valve block.

knowbenz

Does it only sag when the car is off or is it with the engine running also. If it sits level and lowers with the car off then you have a valve block issue or external leak. Make sure the springs on the locking valves have enough tension to keep the solenoid plunger seated with the car off. if the springs are weak it could let some fluid past.

pumpedTSI

Only sags with car off and only on passenger corner. No leaks at valve block or hoses and I did stretch the springs slightly on both valve block rebuilds. I've come to the conclusion that its an internal strut leak and will change the strut this week. When I jump in the car, start it and hit the suspension rise button it pops back up instantly....no issues when running.

knowbenz

I wish you luck but that's not how the system works. What kind of seals did you use on the rebuilds?

ItalianJoe1

The strut acts in theory like a balloon. You blow it up, it raises the car. You let air out, the car goes down. So if it's sagging, fluid is coming out of the strut. The only 2 options, are it's leaving the strut via leakage to the outside (it will be covered in oil, should be readily apparent), or it's going back through the valve block to the reservoir, it can't leak "inside" the strut, it's not that type of design.

pumpedTSI

RESOLVED........ it actually WAS the strut itself. I replaced the strut yesterday and no more sagging......apparently they DO leak internally.

compaddict

iTrader: (1)

Thanks for the data!

knowbenz

Interesting, even Mercedes Benz has published information stating the strut will not make it sag unless external leak. Possible that in changing the strut it helped to dislodge debris in that particular circuit. Either way, good that it is fixed

GrepAwk

Have you had the problem since the strut was replaced?

pumpedTSI

Nope, no suspension related issues however did have some misc "troubles" pop up later......fuel pump took a crap I think and the troubles are related to that (I think), its probably original. I did change the filter a few months ago but waiting on new pump and will change filter again....always fukin something with these and I have pretty much went thru the whole car.....anyways, strut fixed the problem.

maw1124

Are fuel pumps a known item on these? Might be an every 12 year thing, I also hear them going on my '92 500E. It's on the list of "may leave you stranded" items, like CPS. I would always check the relay first, though.

maw

pumpedTSI

Maybe I'll just change the relay with the pump and filter while I'm there.....where is it on the S55?

maw1124

I have no idea. Haven't had to think about it. Try this... http://www.mercedesmedic.com/fuses-a...***-2000-2006/

maw

DRTYLNDY

A few years ago my 2003 S55 kept having a random no start issue. I replaced the CPS twice and still had random no start issues. Replaced the fuel pump and my dad is still driving the car today with no more start issues.
It really left me stumped for a while. The only way I ever figured it out was when it had a no start issue I opened the hood and pushed in the valve on the fuel rail and it had no pressure. Problem solved!
Johan

bavarianfanatic

Digging up an old thread but glad I found it. I have the exact same issue. Was sagging on left rear. Rebuilt the valve block with no resolution. Tried swapping the solenoids side to side. Still sagged on the left. No visible leaks. The only thing I could imagine was the strut itself. I've always heard they don't cause sagging unless they're leaking but here we are. I appreciate your follow-up.