KAROZZA

After sitting for around 5-7 days, my SL55 sinks completely on the front passenger side(same side as the valve block-RHD car). After numerous attempts at overhauling/seals/switching solenoid around in front valve block & even replacing with a another used one, the car remains with the same fault on the same side. Actually it had come to a point that it used to sink a few hours after parking. Now stable at around 5-7 days.

Now, the strange part; the car has no leaks & when the car completely sinks, the reservoir fluid level does not increase. Actually, it seems to decrease just slightly. There has been no loss in fluid over time. If the solenoids are leaking fluid, hence the car dropping on one side, wouldn't this suggest the fluid goes back to the reservoir!?

I have now been told to try & replace a short flexible hose from the strut to the car solid hose, which apparently contains a valve;could this have any affect?

Cheers.

White Spyder

Not trying to be a butt, do a search. Lots of good information on here with better explanations than I could give. If you can hook up to STAR or a MB specific DTC reader and be sure there are no faults. Keep in mind that the system is pressurized and after a time of inactivity that pressure bleeds off a bit. When you start the car cycle the ride hight a time or two and you should be go to go if there are no warnings.

FxFormat

Cars sinking after a week is not a big deal, if it's not leaking, or show signs of failure, just live with it. Mine does the same thing for the past year, if i don't drive it for a week, the front sinks down and as soon as i start the car, it rises right back up. I drive it every couple of days now and it's been fine, no leaks no errors no funny behaviors.

KAROZZA

Car ABC is fully functional with no errors.

I just feel & know other ABC suspension owners don't sink on one side after less than a week. It would be understandable after a few weeks.

If possible, maybe it could be something I can remedy.

Blazeracer

Mine doesn’t sit parked for more than a day, I wouldn’t know anything about this. LOL

KAROZZA

😂

bobterry99

Who told you this? Was it a factory-trained Mercedes Tech with three decades of experience? Your mailman? Whatever, I suggest you ignore that advice. The hydraulic schematic I have shows no valve in that hose.

Mercedes issued a service bulletin to its U.S. dealers stating that sagging was normal after c. one week of being idle. Now, with respect to the bulletin, maybe your car sags a bit too soon. And maybe it sags too fast. At any rate, what you describe is not particularly abnormal. You've already realized a tremendous improvement. I'd be satisfied.

knowbenz

The only way for it to sag when the car is off is internal leak in the valve block, or an external leak at the affected strut or line. Considering the amount of people who have issues with valve block seals, the fact mercedes has a bulletin about it, I wouldn't be surprised if the "new" used one has leaking seals as well. I reseal those blocks weekly, it's pretty common

KAROZZA

It was the tech dept at Arnott, but he did say it was just a suggestion & not sure this was a solution. This was his response;
"I may look into this; can this affect the strut to sink on that side alone? Yes there is a little pressure valve inside that have to close and keeps the oil in the shock if its not running."

KAROZZA

This could be too!

I had resealed the previous valve block multiple times(have done a few others successfully), even switched the solenoids at one point & always resulted with the same side sagging. The original issue was the front sagging.

When I bought the used, as it was from a reputable supplier stating it was in good order, & partly because I was fed up with stripping & re-sealing, I just went ahead & fitted.

So was thinking, either really bad luck, or trying to find if it could be another issue!

Blazeracer

I have replaced a couple of my hydraulic hoses and have put eyes on the strut hoses. No freaking way there is valve inside any of the hoses. At best a hose could have a check ball in it, but then fluid would only flow in one direction. It would be impossible to both raise and lower a strut from a single hydraulic line with a check valve. That would require a valve block with a solenoid. DOH!! I say just drive the car every day. You can't take it with when you die anyway. Smiles per gallon baby!!! I'll be putting about 150 miles on mine today for work, and I get paid mileage.. ;-)

KAROZZA

Thanks for clearing this up Blazeracer & bobterry99....

Unfortunately my business requires a van so cannot use the SL everyday. However I do use regularly on the weekends whenever I can, even the occasional road trip to Europe.

Then, it seems the only real cure is a new Valve Block!

Hendrik Koster

FYI,

Right here > http://w220repair.com/index.php/abc-...oubleshooting/

Best H

KAROZZA

Thanks for the info.

My real query is; if the valve block is at fault, how come the fluid is not returning to the reservoir as previously explained, the fluid level has not increased once the car has sagged!?

If I could know that, I might be able to solve the issue.

bobterry99

It seems perhaps the hose is integral to the strut and isn't an M-B part. If the company that remanufactures the strut states there is a valve, who am I to argue?

I personally would regard that as too much effort and/or expense for little or possibly even no gain at all.

You presently have a resealed valve block. The sagging the car exhibits is a consequence of hydraulic oil leaking past the valve seat of the left-front shutoff valve, I believe. Mercedes' state that one of the purposes of the Rodeo routine is to remove contamination from the valve seat of each strut shutoff valve. If you haven't already, I would suggest two fifteen-minute Rodeo routines run back-to-back.

KAROZZA

Presently, I have a "new" used one fitted. Luckily it seems to be having the same issue. Maybe could try the Rodeo. Although, I have my doubts as I have flushed the system before with the filters replaced each time.

bobterry99

I believe a Rodeo is considerably more capable of removing deposits and contaminants from the valve seats that a flush. One marked difference is that the oil is typically much hotter with a Rodeo, I believe.

Rudeney

One of the things that has always concerned me is that the fluid "downstream" of the valve block, in the line and the shock, is pretty much a "dead end". That fluid doesn't continuously circulate. Using the rodeo to heat the fluid and introduce pretty much the widest range of travel, that's going to be the best way to mix in freshly filtered fluid into the shock and thus dislodge any contaminates and debris so it can be carried back to the filter.

knowbenz

He could be referring to the valve in the quick connect portion, this doesn't prevent fluid flow, that only the valve block.

Did you use the right seals and replace the backup rings also?


Go rebuilt

When the car is running vs idle the fluid level is a couple inches difference. Most of which goes into the accumulators and pulsation dampers, when the car is shut off and the pressure bleeds down that extra fluid goes into the reservoir and the level rises. There isn't a ton of fluid in your struts so the little bit that bleeds down can go into accumulators, and a little back to the reservoir. If you put a cup under the bleeder screw and crack one loose on a 4 post lift its only about 7-10oz that comes out with strut collapsed



This has been discussed in other threads, the majority of that fluid is exchanged during a flush, you may have a very slight amount of residual fluid that quickly gets diluted

ponchik

I wouldnt rely much on the fluid level indicatior. The total amount of fluid in the system is less than 4 liters, and it includes 4 struts, all the lines around the car, pulsation dampeners and the amount in the reservoir. So if you have only one wheel going down, i believe you can easiliy miss the level change. Especially if you don't make any additional marks "before and after".

KAROZZA

Quote:Originally Posted by KAROZZA It was the tech dept at Arnott, but he did say it was just a suggestion & not sure this was a solution. This was his response;
"I may look into this; can this affect the strut to sink on that side alone? Yes there is a little pressure valve inside that have to close and keeps the oil in the shock if its not running."He could be referring to the valve in the quick connect portion, this doesn't prevent fluid flow, that only the valve block. He could be; but I'm not entirely sure what you mean.

Quote:Originally Posted by KAROZZA This could be too!

I had resealed the previous valve block multiple times(have done a few others successfully), even switched the solenoids at one point & always resulted with the same side sagging. The original issue was the front sagging.

When I bought the used, as it was from a reputable supplier stating it was in good order, & partly because I was fed up with stripping & re-sealing, I just went ahead & fitted.

So was thinking, either really bad luck, or trying to find if it could be another issue!Did you use the right seals and replace the backup rings also? To my knowledge yes. Bought them a few times off Ebay specifically for valve blocks, been a while now. Done a few successfully. At one point, a fellow forum member who successfully rebuilds blocks as well, kindly sent me a set of what he uses. Still didn't solve the issue.
Do you have a supplier you trust? I replace all the O rings on each solenoid; which back up rings are you referring to?


Quote:Originally Posted by KAROZZA Thanks for clearing this up Blazeracer & bobterry99....

Unfortunately my business requires a van so cannot use the SL everyday. However I do use regularly on the weekends whenever I can, even the occasional road trip to Europe.

Then, it seems the only real cure is a new Valve Block!Go rebuilt Could do. I still have my previous valve block that I could prepare.

Quote:Originally Posted by KAROZZA Thanks for the info.

My real query is; if the valve block is at fault, how come the fluid is not returning to the reservoir as previously explained, the fluid level has not increased once the car has sagged!?

If I could know that, I might be able to solve the issue.When the car is running vs idle the fluid level is a couple inches difference. Most of which goes into the accumulators and pulsation dampers, when the car is shut off and the pressure bleeds down that extra fluid goes into the reservoir and the level rises. There isn't a ton of fluid in your struts so the little bit that bleeds down can go into accumulators, and a little back to the reservoir. If you put a cup under the bleeder screw and crack one loose on a 4 post lift its only about 7-10oz that comes out with strut collapsed Yes, true. I have checked when "ON" & "OFF" fluid levels are correct.

I took pictures of the level exactly when car was shut down after a run, then checked the level after sagging; ironically it actually looks like the level decreased just slightly!

knowbenz

The PFTE backup rings.

www.DIYBenzRepair.com
IG: @DIYBenzRepair

Full disclosure, thats my website and that was a shameless plug.

KAROZZA

I didn't replace these as they were in good condition; just gave them a good clean. Don't you replace these if they visually look defective, or do you recommend replacing also?