hotgreek

I was trying to repair my valve block but not luck The O-rings that I bought from harbor freight green color they don't fit right Any other brand O-rings? Any one can rebuild the pump for me ? willing to pay
Please help Thank you

Exotic-metal55

I would not use O rings from Harbor freight and would only use high quality o rings. Maybe even use a Viton O ring.

http://www.marcorubber.com/viton.htm

GrepAwk

I have posted on this exact topic. There are a dozen or more types of O-Ring materials.

Which materials are OK to use for O-Rings that are in contact with Pentosin CHF11S hydraulic fluid? Any hydraulic engineers out there? Or MB Techs that can give a definite answer as to which materials are compatible with Pentosin CHF11S?

There are are certain o-rings that will swell too much, or disintegrate in this fluid. The list of which ones not to use may be longer than the list of which ones to use.

I don't trust this system to be happy with following the guidance "Just get the green ones at Harbor Freight".

richvegas

i have now rebuilt 4 valve blocks using the green o-ring pack from harbor freight (HNBR 205 piece kit #67644). they are hydraulic fluid approved and a fine quality. I will only use snap on tools and must have quality equipment and i believe these o-rings work as good or better than stock. it comes with like 12-15 different sizes though you only need 4-5 different ones. all of the rebuilds were successful in solving issues. my s65 was sagging every night, i rebuilt the block a year ago and still no sag even after a 2 week vacation.
hot greek, you can mail me your block and $100 and i'll get it back to you same or next day. you can ask 02cl55amg about my quality of work (i have done all of his abc work)

k1200man

richvegas - I have a 2006 S55 - the square rings in my valves are bad. What have you used to replace them? My experience - have cleaned an replaced O rings with Harbor Freight green o rings and the car will be good for about 3 to 4 days and the will start to leak down. Other question-what did you do to bleed the air from the system?

richvegas

i don't touch the square ones. i believe they are just spacers.
all i do for the bleed is raise and lower the car 10 times and check fluid level. no problems with any so far

k1200man

I have seen in the photos posted that the square rings are white. Mine are black rubber. What have you seen?

richvegas

i have seen both. i've never removed them to feel what they were made of

k1200man

Thank you for the reply. I will probably replace them with Viton quad rings along with Viton o rings. Hopefully it will work this time.

GrepAwk

I received a material interactions file from Pentosin's USA rep.
Thanks to Robert Trevor at CRP Industries.

See attached pdf file

GrepAwk

Comparing the % changes in the material properties in the Pentosin sheet shows that the FKM type of material (Viton) seems to be more stable than the various H-NBR materials they tested.

Do your own comparison.

I'm going with Viton 0-Rings for the ABC.

GrepAwk

It was not too bad. The fluid from the pump to the valve block was pretty dark. But the ORings on the valves were in great shape and the fluid behind the valve block was pretty clear.

I cleaned up and reassembled.

So I have a question: after reading through all the diagrams I can find, I noticed that there should be a large accumulator for the rear, hidden away somewhere. I'm not talking about the return pressure vessel directly connected to the valve block. But rather another larger accumulator that many drawings show as located somewhere up behind the seat.

I tried tracing the lines out of the valve block but can't find it. Where the heck is the thing?

GrepAwk

The large accumulator for the rear struts is located above the right rear muffler. I had to trace one of the pipes out of the Valve Block across to the other side of the car.

I removed and examined it and it appeared the membrane was still intact. So, I reinstalled it.

So as you read through all these threads about refurbishing the rear Valve Block, you should note there is a small "Pressure" vessel at the valve block for the return pressure, and additionally a "Large Accumulator" hidden above the right rear muffler. That's on my '03 S55.

And for the front Valve Block, the same exact "Large Accumulator" for the front struts is connected directly to the Front Valve Block. It is as you see in all the great videos.


Now what I am trying to figure out is why I got the red "ABC Warning. Visit Workshop" message. There was a litte leaking at the front valve block. It appears that the leak had sprayed out of some sort of Pressure Test fitting that had a plastic cap over it. The fitting was part of the pipe connecting Accumulator to Valve Block. Never heard anybody mention this fitting.

V12TTenthusiast

Rich I might have to mail you mine, warranty covered the replacement part, but I figured I get my old one rebuilt when the other valve block goes out lol

NRL

Does anything need to be drained, pinched off, or pressure released to replace the accumulators?
Do I have to bleed the whole system or is there a bleed value just where the accumulator is connected?

GrepAwk

I found very little pressure left in the lines to the accumulators after the car was jacked up om stands for 1hour.

I do not see a bleed valve near the rear accumulator. I suppose if the accumulator is good from a quick inspection, the small amount of fluid loss won't be significant enough to need any bleed. The rear accumulator is on a dead end stub. The closest bleed point is in the line snaking up to the right rear strut.

The front accumulator is close to, and, one might say, right next to the front valve block.

NRL

Any method to finding out which of the 4 accumulator is bad with DAS or not?

I think one accumulator had it's membrane finally go after hitting a big soft dip bump...

No leaks, no weeping, level of fluid, still level is fine, goes up and down fine when error message is gone but I spotted some steam come thru the ports on the ABC dip stick when back on..

Breaking out the DAS..

NRL

Gonna replace all of them..
Ordered the 4 Accumulators.. Preventive maintenance. If one accumulator has a busted membrane, then the others might be due too.

If I find the actual bad accumulator, is it neccessary to bleed that line just in case their is debris in the fluid from the membrane rupturing?

GrepAwk

I just unscrewed them and checked if the membrane was still intact. It was clearly still pressurized and tight up against the opening in all 3 cases that ii was able to check: directly attached to front valve block, directly attached to rear valve block, on a stub terminating above the right muffler.

NRL

still waiting for the accumulators in the mail..
I started by checking the level and changing out the ABC fluid in the reservoir to see if it improves..

DAS is showing 1.9Bar versus the 2.0Bar needed.. no other error codes.

Did a short test and the ride for small bumps is rough,sharp.. really looking like it's one for the accumulators. Don't know which one.

More symptoms, "burping" sound sometimes when I start it.. also a new sound sounding like a "super charger" when accelerating.. maybe it's the pump trying to keep the pressure up since the membrane on the accumulator broke..

Anyone want to guess which accumulator it is?

Front, Rear, Pulsation Damper, Air Cell?

DRTYLNDY

I vote for the pulsation damper, sounds like the way my car behaved when it failed a few years ago.

NRL

I think it was the passenger side accumulator.. AIR Cell, Pulsation Dampner.

But I went ahead and replaced all 4.
All is well. Rides great.

I posted some pics on the "Accumulator" CL65 thread..

v8dve

Does anyone know the actual sizes of the O Rings used in the valve block?

Are they Metric or Imperial? I'm guessing the US guys used imperial....

GrepAwk

Even the o-rings from Luk would be metric in the OEM valves.

That said, I don't know the answer to your question. Maybe you can find it in Howard's maintenance thread.

FYI, we here in USA can buy nuts/bolts/tools in imperial "SAE" or in Metric sizes. When you go to a hardware store, there is a section for SAE bolts, and a section for metric. Same for most every machined fastener.

We don't measure in metric yet for gasoline , food and home building materials. Everything is still sold in terms of gallons, inches or feet or oz/pounds, cubic yards....and I believe "gallons" in USA is different than "Imperial Gallons".

v8dve

Thanks GrepAwk for your reply.

I have looked all over for those sizes and no luck yet, no biggy though

The interesting thing is that I would expect them to be metric on a German Car, but I understood the valve blocks have been manufactured in the US, hence my question about non metric/ metric sizes.

The other reason is some people have replaced the O Rings and still have issues and I wondered if it might attributable to metric / non metric tiny differences which at 150+ bar pressure might be the issue.

I'll know when I pull my valve block apart I guess...