KAROZZA

I have rebuilt mine 3 times & still not 100% happy :fail

The car still drops on the front passenger side & for the first time yesterday, got the first warning; car too low in red.

Would like to run through this with someone, if need be even on pm. I am now rebuilding another for a mechanic & don't want to give up on the challenge as I have read quite a few successful attempts.

The O-rings I found here can withstand 130 degrees Celsius; is this sufficient??

I have also used light compound paste to clean the valve/plunger seat on the return solenoids.

cnterline

Never had any luck just bought 2 new ones

kittyandgary

jnash on this forum, or on the mercedes world forum rebuilds these. Do a search for info on what he does.

kennethcole79

maybe the valve block is not the problem. check for leaking lines, and leaking struts. sound like you have a leak and or bad tandem pump if your getting the red message.

jnash

All,
I would be very leery of attempting to refinish the valve seats on these solenoid valves. We do not know what the surface polishing specs are, or the surface hardness specs for them. It's quite possible the surface has now been compromised. Also, if you have left any grinding paste behind then that's going to be a problem as well. When I rebuild blocks one of the steps I take is to inspect the valve seats under magnification to observe any damage to the valve seat face. If they are damaged, indented, or have marks on the actual face of the these metal seals then I consider it trashed.
So far I have never found a valve seat that has been damaged, suggesting that any material trapped is always software than the valve seat material.
Recently, a few folks on the forums have been trying to repair their own blocks and asking me for help. It's more reliable and less costly for you all, to send me your blocks for rebuilding before you have messed with them.
Hope this helps!
-Jim

coldhammer

I was told the other day that the early model blocks dont respond very well to rebuilding. The best thing to do is locate some used late model blocks and rebuild those. They supposedly respond much better to rebuilding.

jnash

I'm not sure that's true. I've rebuilt plenty of older blocks.

KAROZZA

I don't think that's entirely accurate either.

coldhammer

DUNNO. I cant really say for sure one way or the other. But the guy that told me is a goto mechanic for a lot of the local amg guys who swear by him. He also builds highly modified MB cars for racing as well.

So i put more stock into what he says than if he was some run of the mill dealership or indy mechanic.

What i do know is that most every shop i have talked to over the years have all said they have a very low success rate with rebuilding blocks. I also know that the parts used in the updated blocks are a lot higher quality than the cheap plastic stuff used in the original blocks on the early cars. So it stands to reason that if the parts have been updated numerous times to address failure problems and that part quality of the newer blocks is significantly improved then its quite possible that they may actually respond to a rebuild better than the old blocks.

But either way used newer version blocks are significantly cheaper than finding the old used blocks. So if your old blocks are not holding up to the rebuild perhaps try a newer set of blocks and rebuild those and report back. Obviously your not having success rebuilding what you already have.

jnash

Coldmammer,
Auto repair shops will almost always prefer to replace a part compared to rebuilding a part since their hourly rates are high. So I am not surprised to hear them telling you that they have low success rates at rebuilding ABC blocks. It takes special knowledge and experience to rebuild them that they normally don't practice.
I would have to disagree that old blocks have cheap plastic. Any changes in design are more likely based on ways to reduce manufacturing/assembly costs. The new designed blocks have exactly the same wear points as the older style. That is, they all fail eventually with o-ring wear and the news ones have the same seal o-rings as the old ones.
Also, I cannot agree with your comment that new blocks are significantly cheaper than finding old blocks. New blocks are in excess of $1500 each, and used blocks typically go for more than half this amount.
I successfully rebuild these blocks weekly so I have some experience in this.

jnash

Sorry, I cant agree with this either LOL Old blocks respond well to rebuilding. I do it all the time.