SL/R230: Rebuilt the front valve body but the car does not lift the front
Thread Starter
Senior Member
Joined: Oct 2021
Posts: 493
Likes: 101
From: Benton, Louisiana, USA
SL 500 2004, Ford F-150-2014
Rebuilt the front valve body but the car does not lift the front
Friends, I bought a 2004 SL500 which has the front sagging. After reading several posts, learned that the cure was to rebuilt the valve block. I did so, push the ABC button 20 times and did not see the car lift. I actually let about two quarts of hydraulic fluid to drain while the valve block was out.
I put new oil in the reservoir. I wonder if the problem is due to the system full of air..! Any wise hints to resolve this will be greatly appreciated.!
I put new oil in the reservoir. I wonder if the problem is due to the system full of air..! Any wise hints to resolve this will be greatly appreciated.!
Thread Starter
Senior Member
Joined: Oct 2021
Posts: 493
Likes: 101
From: Benton, Louisiana, USA
SL 500 2004, Ford F-150-2014
Not it didn't..! I wonder how to check the pump pressure..! Since a lot of fluid came out when I removed the hoses from the Valve block, I wonder also if I have to bleed the system!
Senior Member
Joined: Dec 2019
Posts: 406
Likes: 137
From: Houston, TX
2005 SL600
It may be that your pump lost its prime and so is not producing pressure. These pumps are not self-priming; if they run dry, simply refilling the reservior is not enough.
Check the reservior fluid level when the car is off, then when the car is running. The dipstick has marks for both levels.
If the level isn't dropping to the correct level when the car is running, try applying some air pressure to the reservior while the car is running. Mercedes-Benz workshop information specifies 14psi; I've done this using a bicycle tire pump. You can do it using an air compressor, just be careful and don't go overboard with pressure.
Check the reservior fluid level when the car is off, then when the car is running. The dipstick has marks for both levels.
If the level isn't dropping to the correct level when the car is running, try applying some air pressure to the reservior while the car is running. Mercedes-Benz workshop information specifies 14psi; I've done this using a bicycle tire pump. You can do it using an air compressor, just be careful and don't go overboard with pressure.
Senior Member
Joined: Dec 2019
Posts: 406
Likes: 137
From: Houston, TX
2005 SL600
cdk4219 is right - if you plan to regularly DIY on these cars, you're really going to need a diagnostic tool. Without one, you're going to waste a lot of time and money going through trial and error. These cars are very complicated, but they also have a ton of diagnostic information available if you have the tool to access it.
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Thread Starter
Senior Member
Joined: Oct 2021
Posts: 493
Likes: 101
From: Benton, Louisiana, USA
SL 500 2004, Ford F-150-2014
No signs of lifting after applying 15 PSI inside the reservoir.
Friends, I have followed the advice of applying pressure over the reservoir and the level didn't change nor the front lifted. I wonder if I should loosen one of the valve body connections and let it bleed fluid while pressurizing the tank! In theory this should circulate fluid through the conduits, pump and valves.! I purchased the iCarsoft MD II but seems like this unit does not do the ABC.>!
Any hints!
Big thanks!
Any hints!
Big thanks!
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Senior Member
Joined: Jan 2015
Posts: 389
Likes: 113
From: Seattle, WA
SL500
The system self purges air, but it can take a bit of time to rid all of the air (as much as a few days for some more stubborn systems). When I change fluid, I blow up a balloon and then fit it around the reservoir fill spout and squeeze it as someone turns the car on. On a few occasions, the car did not immediately lift and I needed to drive a few blocks, then the suspension will suddenly "pop up". I then cycle it by raising and lowering about 10 times.
