SL55/63/65/R230 AMG: Successful valve block repair!
Thread Starter
Junior Member
Joined: Feb 2016
Posts: 26
Likes: 3
BMW M5 / SL55 AMG
Successful valve block repair!
Hi All!
Rebuilt the front valve block and replaced Accumulator on my 2004 SL55 - 85xxx miles. Sagging after 10 minutes on the front right strut and a transient RED (!) " ACB - Visit Workshop" when hitting some bumps, especially if the bump unloaded the front suspension. Suspension would also bottom on bumps that I thought were not that severe - all indications that the valves were leaking and the accumulator was shot.
This repair is pretty straight forward using the many tutorials on this forum and others, but thought I would add my observations in case anyone else finds them useful. I took plenty of photos so I could retrace my steps and remember what went where, which I heartily recommend for anyone doing this for the first time.
Observations: There are only five hoses, 4 electrical connections for the system and three attachment points for holding the assembly in. Pretty easy to get to once the fender liner is removed. EXCEPT for a blind nut on the side of the assembly chassis (See the attached photo) that was a screaming bit@h to get to. Spent most of my frustrations on that one nut till I went out and bought a 13MM ratcheting box wrench which finally allowed the nut to be turned one flat at a time till it was loose enough to finish by hand. Is there a trick to this that I missed, since none of the write-ups I saw on any of the forums warned of the fiddly, close quarter, knucklebuster effort to remove this one nut from the stud.
Once off the car, the assembly came apart in a follow your noise manner, leaving the valve block and solenoids to be worked on. Removing the locking clamps was easy enough, mine had one piece locking units that I could release using two pairs of pliers to squeeze the both sides at the same time and slide them off. Sorry, no photos, but it is obvious once you see it.
All the instructions I had read said something on the order of "twist 45 or 90 degrees and the solenoid / valve body comes off". Yeah, right! It took a padded bench vice and careful use of a small pipe wrench (covered with a piece of cloth) to break them loose and get them to turn, and they would happily spin in place 360 degrees without any indication that they were ready to separate from the valve block. I had to turn and pull at the same time to get them to disconnect from the valve block. Would have been easier if I had looked at the many photos available that show how the solenoids lock into the valve block, but I tend to learn the hard way.
Once off, it was clear that this was not their first rebuild, because the Teflon spacers were gone and replaced with square "O" rings. Funny thing, is it was these square "O" rings that had started to fray and come apart - not the O rings, (see photo) causing the valve seating issues and sagging. Fortunately I had ordered a replacement set from a poster on this site (E BAY) that contained replacement square O rings. Let's just hope it is not the same type that was on already and failed!
Lots of brake cleaner and canned air cleaned the valve bodies up nicely and installing the replacement square and round "O" rings was pretty straightforward. Against the advice of my motorcycle mechanic son, I chose to install them "dry" since the one I tried to do when lubed with Pentosin was too slippery to handle. Your experience might differ, but it was 10 minutes of greasy frustrations and foul language compared to 2 minutes of easy satisfaction on the ones I did dry. If you use a kit replacing the Teflon spacers with square O rings, take time and effort to make sure that they are not twisted - it is easy to do and hard to see (I wonder if this is what happened to the previous set on my valves).
To reinstall the valves into the valve block, I lubed the valves and the block with Pentosin and slid them in. It takes considerable pressure to get them seated, so a padded vice positioned so that you can put your weight on the solenoid while turning is a good idea. Now that you have seen how the solenoids lock in place, it is a simple but forceful task.
Reassembly of the unit including the new accumulator was easy and since I had plenty of photos, replacement into the car was just as easy. I needed a liter of Pentosin to bring the system up to the full marks, but success! No sagging and no transient warnings on bumps. Ride seems better too.
Full disclosure - during reassembly, one of the electrical connectors on a solenoid (of course it was one of the ones totally hidden away on back side of the unit once installed) somehow came off. Proud of his work, yours truly had put everything back together, including the fender liner and full torque on the left front wheel studs. The triumphant restarting of the car resulted in a spectacular array of dings, white and red warnings and the front of the car totally slammed to the ground. Of course it was late in the day, so all that could be done was to let loose with a magnificent and thoughtful stream of foul language - the type that scares the dog and makes the wife giggle - and then go to bed. Retracing in the clear light of day revealed the missing connection, so be sure to check and double check that nothing is knocked loose during reassembly. There has been speculation in this household that some dumbass simply forgot to attach the connector, but that theory has been disputed and totally discredited.
Rebuilt the front valve block and replaced Accumulator on my 2004 SL55 - 85xxx miles. Sagging after 10 minutes on the front right strut and a transient RED (!) " ACB - Visit Workshop" when hitting some bumps, especially if the bump unloaded the front suspension. Suspension would also bottom on bumps that I thought were not that severe - all indications that the valves were leaking and the accumulator was shot.
This repair is pretty straight forward using the many tutorials on this forum and others, but thought I would add my observations in case anyone else finds them useful. I took plenty of photos so I could retrace my steps and remember what went where, which I heartily recommend for anyone doing this for the first time.
Observations: There are only five hoses, 4 electrical connections for the system and three attachment points for holding the assembly in. Pretty easy to get to once the fender liner is removed. EXCEPT for a blind nut on the side of the assembly chassis (See the attached photo) that was a screaming bit@h to get to. Spent most of my frustrations on that one nut till I went out and bought a 13MM ratcheting box wrench which finally allowed the nut to be turned one flat at a time till it was loose enough to finish by hand. Is there a trick to this that I missed, since none of the write-ups I saw on any of the forums warned of the fiddly, close quarter, knucklebuster effort to remove this one nut from the stud.
Once off the car, the assembly came apart in a follow your noise manner, leaving the valve block and solenoids to be worked on. Removing the locking clamps was easy enough, mine had one piece locking units that I could release using two pairs of pliers to squeeze the both sides at the same time and slide them off. Sorry, no photos, but it is obvious once you see it.
All the instructions I had read said something on the order of "twist 45 or 90 degrees and the solenoid / valve body comes off". Yeah, right! It took a padded bench vice and careful use of a small pipe wrench (covered with a piece of cloth) to break them loose and get them to turn, and they would happily spin in place 360 degrees without any indication that they were ready to separate from the valve block. I had to turn and pull at the same time to get them to disconnect from the valve block. Would have been easier if I had looked at the many photos available that show how the solenoids lock into the valve block, but I tend to learn the hard way.
Once off, it was clear that this was not their first rebuild, because the Teflon spacers were gone and replaced with square "O" rings. Funny thing, is it was these square "O" rings that had started to fray and come apart - not the O rings, (see photo) causing the valve seating issues and sagging. Fortunately I had ordered a replacement set from a poster on this site (E BAY) that contained replacement square O rings. Let's just hope it is not the same type that was on already and failed!
Lots of brake cleaner and canned air cleaned the valve bodies up nicely and installing the replacement square and round "O" rings was pretty straightforward. Against the advice of my motorcycle mechanic son, I chose to install them "dry" since the one I tried to do when lubed with Pentosin was too slippery to handle. Your experience might differ, but it was 10 minutes of greasy frustrations and foul language compared to 2 minutes of easy satisfaction on the ones I did dry. If you use a kit replacing the Teflon spacers with square O rings, take time and effort to make sure that they are not twisted - it is easy to do and hard to see (I wonder if this is what happened to the previous set on my valves).
To reinstall the valves into the valve block, I lubed the valves and the block with Pentosin and slid them in. It takes considerable pressure to get them seated, so a padded vice positioned so that you can put your weight on the solenoid while turning is a good idea. Now that you have seen how the solenoids lock in place, it is a simple but forceful task.
Reassembly of the unit including the new accumulator was easy and since I had plenty of photos, replacement into the car was just as easy. I needed a liter of Pentosin to bring the system up to the full marks, but success! No sagging and no transient warnings on bumps. Ride seems better too.
Full disclosure - during reassembly, one of the electrical connectors on a solenoid (of course it was one of the ones totally hidden away on back side of the unit once installed) somehow came off. Proud of his work, yours truly had put everything back together, including the fender liner and full torque on the left front wheel studs. The triumphant restarting of the car resulted in a spectacular array of dings, white and red warnings and the front of the car totally slammed to the ground. Of course it was late in the day, so all that could be done was to let loose with a magnificent and thoughtful stream of foul language - the type that scares the dog and makes the wife giggle - and then go to bed. Retracing in the clear light of day revealed the missing connection, so be sure to check and double check that nothing is knocked loose during reassembly. There has been speculation in this household that some dumbass simply forgot to attach the connector, but that theory has been disputed and totally discredited.
Junior Member
Joined: Dec 2009
Posts: 60
Likes: 4
SL500-R230
Old thread I know, but invaluable info on the 13mm nut location
posting to add the solution to access....
https://www.drapertools.com/product/...t-Ring-Spanner
Really stuggling with seized flange bolts though
posting to add the solution to access....
https://www.drapertools.com/product/...t-Ring-Spanner
Really stuggling with seized flange bolts though
