Posted this in R230 AMG section but figured I would post here also incase some were interested since this problem happens a lot. The same valve blocks can be found in CL500 CL55 CL600 CL65 S500 S55 S65 Sl65 SL600 SL500 with ABC suspension

So I helped a friend of mine with a 2004 SL55 reseal one of his ABC valve blocks. His car would lower the front end after sitting for a few hours. He had tried getting the fluid flushed and new filter but it didn't help. He asked me to take pictures along the way so I thought I would share.

First step was to remove the valve block from the vehicle. I didn't take any pictures along the way but these are the tools I used minus a 17mm and breaker bar to remove the LF wheel
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Be sure to clean the surrounding area really well before removal to avoid getting any dirt into the lines

Here is the valve block out of the car, excuse the paint markings in the wrong spot as I quickly put the valves back in for a picture but put in opposite spots lol
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First step is to remove the plastic clips that hold the valves together. How I usually do this is to release one tab on one valve and turn it out of position so I don't have to fiddle with two sides at once, the turned side will be off of the lock tab that holds the clip in place. Here is an overhead view, notice it is only slightly turned. If you turn it too much it will be difficult to remove the clip.
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Once it is slightly turned I use a small screwdriver to push the clip out of the way and place another small screwdriver under the base of the clip to put a little pressure upwards
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From there I leave one screwdriver underneath the clip and then loosen the clip on the other side of where that screwdriver is. once you push the clip off the lock it tends to move up and then I put the little screwdriver underneath and work it up from side to side
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Do the same for the other pair of valves. For the locking valves I use my hand for the upward pressure as the clip is in the middle of the valves. From here you can rotate the valves 90 degrees on the control valves and about 45 degrees on the locking valves and then they can be pulled out of the valve block.
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The big O-rings at the base of valves just seal outside moisture and such from getting in, They are not under hydraulic pressure so if they look a little dry it's OK. I have seen the tall ones replaced by using two O-rings, or using one O-ring and a small bead of silicone around the outside. Either way works.

I have never replaced or seen replaced the fat greenish blue O-ring on the shaft of the locking valve, I usually give everything a good cleaning and put the plungers back in with some new hydraulic fluid as lubricant. The springs on the plungers can be removed, I squeeze them to get a feel of strength, never had to replace them, I usually give them a little stretch to make just a hair longer incase they have become compressed over time.
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Inspect the white teflon spacers for any kind of damage, these rings don't offer any sealing, they mainly offer support to the sealing O-ring to help keep it in place. If they are damaged they can be replaced with rubber o-ring. The rings on these valves were in good shape so They just got a good cleaning with a tooth brush and a little solvent.
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Here is a few pictures of the valves with their respective seals that will be getting installed after the valves receive a thorough cleaning. I didn't take pictures but I always like to apply power to the control valves in both directions and run solvent both ways through the passages just incase some gunk is caught up inside the valve. Also be sure and thoroughly clean the aluminum housing to get all old fluid and debris out of it.
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After it is all cleaned up and new O-rings installed it's time to put the valves back in. I use plenty of new hydraulic oil to lubricate the valve with o-rings as well as the valve block itself. I always try and turn the valves in clockwise, sometimes the valve comes loose from housing turning the opposite way. Take your time putting them in to ensure you don't pinch an o-ring.
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Once all valves are in place it's time to put the clips back on. Simply push the clips in between the valves and down into position.
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Double check you have 14 old o-rings and no new o-rings on your workbench. After that put the valve block back in the car.
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thanks, great info.

 

Nice write up.

Those white teflon seals do seal though, they are used because they don't shear like a rubber o-ring will tend to with repeated oscillation. But, as you said, unless they are damaged there's basically no reason to change them, they don't really wear out as teflon is super durable as a sealing surface and perfect for that application, and also won't degrade when exposed to CHF-11 like most rubber/plastic.

 

Great post. My passenger rear sags overnight. Had the fluid and filters changed. Is there a block on each corner? Where did you get the O ring kits? Tx! Tom

 

there are two valve blocks, one for front and one for rear. Got the o-rings on Ebay. Search "ABC valve block seal kit" and it pops up. They have them with and without the square space to-rings

 

Thought I would throw this up here also. Did a second valve block using the square o-ring kit. The first one with square o-rings I did and the one from the first post on this thread are still holding up great. Pretty much everything is the same except for cutting off the teflon rings and replacing with a rubber square cut o-ring.

These didn't necessarily need to be replaced as the condition looked good. I started off by measuring all the different spots on the solenoid just to compare with the new rubber square rings. I've seen a kit before that that square rings were way to big and got cut upon installation.




I used a razor blade to cut the teflon rings off, they can also be removed like the o-rings with a seal tool or pocket screwdriver.




Here is everything being replaced with this kit, x2 for the other pair of valves not pictured




Install the new o-rings starting from the biggest side and go down in order. It is sometimes difficult to get a square o-ring around the round o-ring. Do one valve at a time so you don't forget the order they go, or just refer back to this thread.




As you can see the square rings don't protrude past the valves surface just how the teflon rings don't. Also, what is hard to capture on camera is that there is a slight amount of room left between the seals to allow for expansion of o-ring when the main o-ring gets compressed which is the same with the teflon rings installed.

The other setup I have seen has square rings that are damn near the same diameter as the round o-ring which makes installing the valve extremely difficult and ends up sheering off a few thousandths from the square rings and leaving loose rubber debris to make it's way into the hydraulic circuit.

One thing i want to stress is to make sure the square o-rings don't roll over when installing, it's easy to miss a small section that may not be fully seated and has to be rolled a little more. I found this out the hard way, the top seal on one control valve wasn't fully in place so when I went to install it it got cut. I should have rechecked when I realized this one was being a little difficult to get seated. Use lots of lube and twist back and forth the slight amount that it will to seat everything. I contacted the seller about the o-ring I broke and he asked which one it was and dropped one in the mail the same day. I should get it tomorrow and have this valve block wrapped up.

 

Does anyone offer a teflon seal kit? They would be a little more work to install but they could be done using a tool like the one for Ford power steering hose teflon seals.

 

I've seen the split PTFE rings used. Also heard of the non-split rings being used although tougher to install. I've always used rubber when needed and never had an issue aside from not properly seating one before install lol

 

who is the vender for the o-rings?

 

Ebay user unitextured or search Ebay for "abc valve block seal kit"

 

hello, going to start on my rebuilt for my front valve block today - 03 S55. how difficult is it to remove? there are many pics/vids/instructions to rebuild, but not much on removing/taking it out. thanks in advance

 

Take the fender liner off of LF wheel and you will see the block there. Disconnect all the lines, disconnect electrical connectors, unbolt block

 

yea, got it all done. these are pretty awesome