ABC valve cleaning DIY - Mercedes-Benz Forum

LinkBack Thread Tools Display Modes
post #1 of 83 (permalink) Old 02-10-2012, 12:53 PM Thread Starter
BenzWorld Newbie
Date registered: Feb 2012
Vehicle: Mercedes SL500 2003 designo edition
Location: San Francisco CA
Posts: 3
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
(Thread Starter)
ABC valve cleaning DIY

Car: 2003 Mercedes SL500

Symptoms: car’s front drops 3-4” within 1 hour after engine is off, after engine start car height goes to normal. Red ABC 'low height' warning message is displayed every time I start the car but goes away in 30 sec or so.

Since there where no external leaks on shocks/lines it must be internal leak in ABC valve block. Nice description of ABC suspension is here ABC Suspension
So after reading many posts I thought I should try cleaning valves before replacing them (cheapest unit I can find was $1200 from ESC tuning
2003 Mercedes Benz SL500 Base V8 5.0L > Suspension > OEM > ES#1780752 Control Valve For Active Body Control - 2203201258

here is place where they rebuild them
00-06 Mercedes Benz Suspension Valve Block A2203200358

It took 3 hours of pretty dirty and unpleasant work but results are impressive – car stopped dropping and ride became much more stiff and sporty.

Because I cannot find anywhere in internet info on how exactly to clean ABC valve blocks I thought I would write brief DIY sequence here:
1. Block access: raise front axe and remove front left wheel and wheel liner
A lot of pictures can be found here
2. Bleed residual pressure with both front wheels off the ground using small bleeding screws on the front shock lines
3. Now you are ready to remove valve block and take it home for cleaning. There are many ways how you can do it but here is what I did:
a. Disconnect Line 1 and Line 2 from aluminum Block 1 Pic 1. To avoid contamination in hydraulic system I put saran wrap/electrical tape at the end of each line. Oh and use gloves!
b. Remove 10 mm Bolt 1 which holds Block 1 on bracket and electrical connector to the sensor, slide Block 1 to the side
c. Remove Lines 3-5
d. There are 3 10 mm nuts which hold Valve block – now you can access them and remove Valve Block
e. Carefully mark and remove 4 electric connectors - they are fragile!
f. Put plastic tray under car - lines are not leaking badly but I got 0.5 l of oil over 2 hours..
4. Now with Valve Block off the car you can take pressure damper and holding brackets off (big black bulb and black metal plates, all 10 mm)
5. Carefully clean block outside with ethanol and remove Plastic Clip which holds valves together, plastic clip between regulating valves is shown on Pic.2 (From here I will write for Check Valves only, Regulating Valves are similar). Plastic clips are fragile! Use two pair of pliers to press them on both sides and slide them out
6. Use adjustable pliers to carefully turn valve (garb at the VALVE BASE) to 45 degree angle: after some wiggling it should come out.
7. There is a spring for each check valve – do not miss them! Picture of all valves taken apart is here
8. Clean valve with soft tissue/ethanol, Pic.3, remove plunger and clean its internal o-ring (mine blue 0-ring was very dirty). Check valve seat for scratches. There are 3 areas which can cause leak: dirty valve seat, leaking o-ring or weak returning spring. To be safe I stretched spring for a bit ..
9. For regulating valves plunger is not removable so I just pushed it back and forth with pliers while spraying with ethanol.
10. Put everything back together (except front wheel liner), check fluid level in ABC tank, add Pentosin 11s if necessary. Start engine with wheels on the ground and stop after 1-2min for 5-10 min, add more Pentosin. Now you are ready to bleed the system – slowly cycle through height modes 15 times, it should be enough. Go check for leaks around valve block. If there are no leaks put liner back.
11. Open your beer and celebrate – you just fixed your Mercedes and saved yourself $2000!

PS To be hones you don’t have to remove valve block to clean valves, but it is just much easier to do so for the first time
Attached Images
File Type: jpg Picture3.jpg (25.0 KB, 7948 views)
File Type: jpg Picture2.jpg (25.0 KB, 9644 views)
File Type: jpg Picture1.jpg (24.5 KB, 9926 views)
esethree likes this.
Valentin SL500 is offline  
Sponsored Links
post #2 of 83 (permalink) Old 02-10-2012, 05:23 PM
BenzWorld Member
Date registered: Feb 2010
Posts: 72
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Very impressive Valentin SL500 .

Sadly , I could have used this excellent thread six months ago . Sadistically , I can't wait for my rear valve block to go , so I can try your brilliant fix .
Well done .
GET TUBED is offline  
post #3 of 83 (permalink) Old 02-26-2012, 05:35 PM
BenzWorld Newbie
Date registered: Sep 2009
Posts: 1
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Thanks for this Excellent Thread!
Question; If the o-rings need replacement (I would think at this point of disassembly one would replace o-rings as a preventative measure anyway), are the o rings made out of a "special" material or just off the shelf o-rings? If they are special, where would I find them for purchase?

Glock3540 is offline  
post #4 of 83 (permalink) Old 02-28-2012, 10:26 AM
BenzWorld Junior Member
Date registered: Nov 2011
Posts: 29
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Amazing write up many thanks.

Excuse my ignorance does the car only have 1 valve block?

Think we use different termonology here. I like the sound of a sportier / stiffer ride as mine seems to be a little, how should I say, loose!


Monky is offline  
post #5 of 83 (permalink) Old 03-03-2012, 07:37 PM
BenzWorld Veteran
danger450's Avatar
Date registered: Jan 2007
Location: Jacksonville Beach, Florida; USA
Posts: 695
Mentioned: 0 Post(s)
Quoted: 5 Post(s)
Send a message via AIM to danger450 Send a message via Yahoo to danger450
AWESOME GUIDE ! Mine is starting to do the same thing, i just wanna rip the whole thing out somdays and use 2x4's to keep the car up, LOL ...

2003 SL500 "AMG SPORT" Brilliant Silver Met.
OPTIONS: SL1, SL2, SL3, 051, 889
MODS: 2009 AMG E63 rims, 2012-Style Arrow LED mirror covers
(with LED ground, courtesy light wired to the dome light), tint,
LED projector city lights, clear lenses, Amber-chrome blinker bulbs,
clear third brake light.
Stay on top of your ABC Maintenance! It is NOT in A or B Flex Service's!
Change FLUID AND FILTER at least every 40,000 miles!
danger450 is offline  
post #6 of 83 (permalink) Old 03-29-2012, 10:26 AM Thread Starter
BenzWorld Newbie
Date registered: Feb 2012
Vehicle: Mercedes SL500 2003 designo edition
Location: San Francisco CA
Posts: 3
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
(Thread Starter)
Regarding o-rings

For check valve I used Atlas O-rings from McMaster catalog - they are 0.07" width, bottom one 9/16" ID and 11/16" OD; top one 5/8" ID and 3/4" OD.
They fit a bit tight so be careful inserting valves back. So far 1,5 month of trouble free ride!
Valentin SL500 is offline  
post #7 of 83 (permalink) Old 05-21-2012, 08:20 PM
BenzWorld Newbie
Date registered: May 2012
Vehicle: 2005 SL500
Location: Louisville, Kentucky
Posts: 2
Mentioned: 0 Post(s)
Quoted: 0 Post(s)

I have a 2005 sl500. For the past 2 years, I have had to raise my car each morning. My driver side sits on the wheels - front and back. I get the red ABC warning "stop - car too low." I raise and lower it and it is fine for the rest of the day.

I search for puddles/drips and I find nothing. So, I am going to ask a mechanic friend to clean both valve blocks for me. My question is, Do you have to drain the ABC fluid before taking the valve blocks off? I am not familiar with them enough to know if taking them off will cause all the fluid to drain out.

Thank you. I really want to save myself the 4 to 5 thousand I was quoted to replace both valve blocks.
Cubby8 is offline  
post #8 of 83 (permalink) Old 05-22-2012, 11:02 AM Thread Starter
BenzWorld Newbie
Date registered: Feb 2012
Vehicle: Mercedes SL500 2003 designo edition
Location: San Francisco CA
Posts: 3
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
(Thread Starter)
No it is not necessary to drain ABC fluid before valve replacement/repair but you will lose some (around 1/2 quarter) when you will disconnect hoses. After you will put everything back it be a good idea to replace fluid anyways. And since your car is 2005 just running rodeo and replacing fluid may fix your problem..
Valentin SL500 is offline  
post #9 of 83 (permalink) Old 05-22-2012, 12:18 PM
BenzWorld Newbie
Date registered: May 2012
Vehicle: 2005 SL500
Location: Louisville, Kentucky
Posts: 2
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Thank you.
Cubby8 is offline  
post #10 of 83 (permalink) Old 06-06-2012, 08:04 PM
BenzWorld Member
Date registered: Dec 2007
Vehicle: 2003 SL500, 2005 ML500SE, 2005 CLK500 Cabriolet Avantgarde
Location: Washington DC Metro.
Posts: 249
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
This has to be one of the greatest posts on this forum!

I look forward to insight from others that have attempted this. I am sure as many of us attempt this repair that would greatly enrich the solution. I spoke with the owner of the California company that claims to rebuild these valves. I always wondered what exactly they did, but the fella was evasive with his answers (trade secrets I guess). But now I know .

Thanks Valentin SL500 for sharing!

Where exactly can one purchase the Atlas O-rings? Also, would you have any idea about where to purchase the spring if needed?
rorypff likes this.
egwu is offline  
Sponsored Links

  Mercedes-Benz Forum > Mercedes-Benz Roadster Forums > R230 SL-Class

Quick Reply

Register Now

In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Topic Author Forum Replies Last Post
DIY on EGR valve cleaning? AMGSingh C208/A208 CLK-Class 8 12-05-2011 08:36 AM
EGR Valve cleaning. BumblebeeLotus C208/A208 CLK-Class 2 10-16-2010 05:42 PM
EGR VALVE PIPE CLEANING Prochambers W126 S,SE,SEC,SEL,SD,SDL Class 5 05-08-2008 08:40 AM
valve body cleaning ? 190jerry W201 190-Class 0 05-08-2008 07:51 AM
Cleaning EGR Valve kburns1969 W202 C-Class 0 08-08-2006 10:02 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Title goes here

video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome