SL/R230: Can anything besides a bad valve block cause sagging if there are no visible leaks??
Thread Starter
Senior Member
Joined: Nov 2019
Posts: 347
Likes: 86
2005 SL65 AMG
Can anything besides a bad valve block cause sagging if there are no visible leaks??
Has anyone ever had a sagging problem that was NOT caused by a valve block?
Valve blocks have been rebuilt, ABC fluid has been flushed twice, filter replaced multiple times, multiple rodeos. After all this the car is still sagging almost immediately and the worst corner (rear left) is all the way down within a few hours.
No fluid leaking.
I’m fed up with this and about to spend $$$ on a new valve block from the dealer.
Before I do this, I want to make sure sagging can only be caused by the valve block and not something else like a bad strut.
Valve blocks have been rebuilt, ABC fluid has been flushed twice, filter replaced multiple times, multiple rodeos. After all this the car is still sagging almost immediately and the worst corner (rear left) is all the way down within a few hours.
No fluid leaking.
I’m fed up with this and about to spend $$$ on a new valve block from the dealer.
Before I do this, I want to make sure sagging can only be caused by the valve block and not something else like a bad strut.
Senior Member
Joined: Apr 2007
Posts: 436
Likes: 79
Former R230, W220 and W221 owner
Has anyone ever had a sagging problem that was NOT caused by a valve block?
Valve blocks have been rebuilt, ABC fluid has been flushed twice, filter replaced multiple times, multiple rodeos. After all this the car is still sagging almost immediately and the worst corner (rear left) is all the way down within a few hours.
No fluid leaking.
I’m fed up with this and about to spend $$$ on a new valve block from the dealer.
Before I do this, I want to make sure sagging can only be caused by the valve block and not something else like a bad strut.
Valve blocks have been rebuilt, ABC fluid has been flushed twice, filter replaced multiple times, multiple rodeos. After all this the car is still sagging almost immediately and the worst corner (rear left) is all the way down within a few hours.
No fluid leaking.
I’m fed up with this and about to spend $$$ on a new valve block from the dealer.
Before I do this, I want to make sure sagging can only be caused by the valve block and not something else like a bad strut.
Member
Joined: Sep 2013
Posts: 157
Likes: 33
From: Walpole, MA USA
2004 SL500
Try this test, run the car, set the suspension to its highest setting and shut it off. See if the sagging continue to occur.
I'm basing this off of an earlier thread where someone noted that resting at the highest setting activated a different part of the solenoid in the valve block and possibly masks the condition, but in this case it may point to your valve block as the culprit, specifically the locking rings and o-rings.
I would also suggest that you watch the fluid level in the tank, both before you start the car to set it to it's highest level, and then after (if it sags). If the fluid level increases in conjunction with the sag, I would think this points to your rings in the valve block.
I'm basing this off of an earlier thread where someone noted that resting at the highest setting activated a different part of the solenoid in the valve block and possibly masks the condition, but in this case it may point to your valve block as the culprit, specifically the locking rings and o-rings.
I would also suggest that you watch the fluid level in the tank, both before you start the car to set it to it's highest level, and then after (if it sags). If the fluid level increases in conjunction with the sag, I would think this points to your rings in the valve block.
Junior Member
Joined: Nov 2019
Posts: 62
Likes: 5
SL 500 r230
To my understanding, the strut has no way of internally leaking the pressure, as there is no return line. I conclude from that, that the strut can only sag AND loose oil to the outside. But it may be, that the oil would accumulate behind the rubber dust sleeve. So you would not see any oil on the ground immediately.
If the strut really doesn't loose any oil, then I would also assume a faulty valve block.
If the valve block has been revised lately, there is a slim chance that it was done incorrectly or with faulty O-rings. And then there is the fact, that there are metal to metal sealing surfaces (and non O-ring seals that are usually not changed), that can not easily be redone but still can cause sagging.
How is your oil? is it fresh? No rubber debris in it from old failing seals? That kind of trash might also cause that kind of trouble.
If the strut really doesn't loose any oil, then I would also assume a faulty valve block.
If the valve block has been revised lately, there is a slim chance that it was done incorrectly or with faulty O-rings. And then there is the fact, that there are metal to metal sealing surfaces (and non O-ring seals that are usually not changed), that can not easily be redone but still can cause sagging.
How is your oil? is it fresh? No rubber debris in it from old failing seals? That kind of trash might also cause that kind of trouble.
