SBC braking system? Take it to Mercedes

[desert]

Just a word of advise based on my personal experience. If you have a Mercedes with the SBC brake system it's probably a good idea to let Mercedes do a brake pad/ roter/flush job on it unless your independent shop has all the Mercedes related computer equipment such as Star. I had a good local shop do everything and I'm sure they did a good job and I saved money ( initially) but since they didn't have a Star computer or what ever Marcedes uses for a complete brake job the pump kept going on and off and I finally had to take it to Mercedes to get it back to normal which of course cost me extra. My Service Advisor at Mercedes said even their mechanics have a hard time with the SBC system. Guess that's why Mercedes no longer uses the SBC system, just too complicated and that's saying something if Mercedes thinks it's too complicated. Also says something that Mercedes has extended the pump warranty to ten years or 100,000K miles....Desert

[mbzman]

I was under the impression that you needed Star Diagnostics to properly service the brakes on a SBC equipped car. I know it was discontinued on W211s after '06 but I believe it continued on the R230 SL cars. What did the dealer have to do?

[bhatt]

SBC can be serviced like any other brake system, with one minor difference.

The SBC pump can come on under a variety of conditions. These include driving through wet areas (the system will lightly apply the brakes to dry the pads), opening the drivers door, etc.

You basically need to disable the pump before working on brakes, otherwise bad things can happen (you can lose a finger if someone opens the door or unlocks the car)

There are 2 ways to do this:
1. Disable SBC with the Mercedes Star (DAS) computer
2. Unplug the SBC pump

#2 is much easier and can be done in a few seconds. Just unplug the connector, service the brakes, then reconnect.

[desert]

As I said, I had the brakes/pads/rotors and sensors redone at my local indepemdent shop that has done brakes on my 280SL and other good AC work for me. I advised them that the car had SBC and that the system would have to be disabled prior to work for safety reasons. They seemed comfortable working on in but once it was back together the pump kept going on and off so I took it back and they tried to reset the SBC but without success. They finally ( after considerable research) said that they couldn't correct the problem without computerized diagonsis IE: the Star. I took it to Mercedes and they hooked it up to their computer and it wasn't showing any errors but still malfunctiong so they finally re-flushed the entire brake system and that solved the problem, the pump now is back to normal. As my MB Service Advisor said, the SBC system gives their mechanics fits sometimes and they have had good independent shops in town having to bring SBC cars into them to get them right.Moral of the story, leave SBC work to Mercedes.

[bhatt]

Still seems odd to me that the system gave no error codes, but they were able to fix it with a flush.

The flush would only replace brake fluid, not affect any of the electronics.

I suspect they charged you for a flush, and as part of the flush they had to disable/re-enable SBC. There is a "reset" function in DAS which they likely used during the re-enable which clears any problems in these 'seized-up' systems.

Any indy with a DAS computer or compatible unit could have done the same. If you are going to keep this car for a while, find an indy who has a DAS computer or compatible. These things cost well under $1000 to buy so most indys that work on MB have one.

[desert]

I'm sure you are right, the electronics probably were not the problem or it would have shown an error code, maybe some air in the system from the original brake job flush but local shop thought electronics were causing the problem since they had disabled the SBC. We do have independent MB shops in Tucson and I'm sure they have the right computers but my shop is not specialized so I won't take the car back there for anything that involves on board computers( which is just about everything as I understand it)....flush job and much head scratching at Mercedes cost $200 which considering the time they spent on the car reasonable to me. I will be keeping the car ( 2004 wagon E320) for quite a while, it only has 34K on it and is in perfect shape.

[duxthe1]

Hell, the I've seen the SBC throw a code that said "Fluid contaminated, flush brakes". Yes it will throw a code for dirty fluid.