My rear brake pads and rotors need to be replaced and I was hoping to do the job myself. However, I just learned that the electric booster pump system on this model can energize and actuate the braking system if the car is jacked up or when the E-brake is released, which I would have to do to remove the rotors. Apparently, this could result in the pistons being pushed out of the calipers when removed and brake fluid leaking out. Obviously not something I want to deal with. Is there a tool I can buy to interface with the car's computer to deactivate the braking system? I really can't afford to take it to the dealer as they want $500 just in labor to replace pads and rotors.

Any help is appreciated.

Gary

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Gary

1992 300E, 2006 E350 and 2006 C230 Sport

Disconnecting the batteries works very well to disable the system. You can also unplug the SBC harness. (I'm a worrier, the batteries would be disconnected for me, though you then have to run the resets.)

And the worst case scenario is not blowing out the pistons and leaking fluid. It's losing a finger that's in the wrong place when the system energizes.

Good luck.

What's involved in running the resets? Is it something I can do without any special tools?

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Gary

1992 300E, 2006 E350 and 2006 C230 Sport

On the W210 its resyncing all the windows and sunroof, calibrating the steering angle sensor with a lock-to-lock wheel turn, and entering the radio code. It may be in your owner's manual.

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Prost!

Didn't see anything in the owner's manual in the section on replacing the battery. Not sure, but I think it's a W211 I've got, right? If I need to do that is it just a matter of cycling the various items through their full travel? Does the computer give you any prompts on the Nav screen? Does the 06 have an adaptive system that needs to relearn how I drive?

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Gary

1992 300E, 2006 E350 and 2006 C230 Sport

I unplugged the SBC unit, without disconnect the battery.

Jack

i've read, though, that the pressurized accumulator can still activate the braking system even when the SBC is unplugged. Anyone know if this is true?

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Gary

1992 300E, 2006 E350 and 2006 C230 Sport

You do indeed have a 211. And you do have an adaptive system, but that is no issue anyway; it doesn't reset from a simple battery disconnect. The windows, sunroof and steering angle sensor are the biggies (you get malfunctions on startup after the battery disconnect, turn the wheel lock-to-lock a couple of times and then shut down, on restart those should clear).

The concerns about residual voltage in the system are why I'd prefer the battery disconnect (and be sure the key is in your pocket, never connect or disconnect the battery with the key in the slot). If you then step on the brake pedal (before doing anything else) for half a minute, that will discharge any stored energy.

The disconnect will reset the ECU for trouble codes and several emission systems will not be in the ready state for a period of time afterward, so if you're close to an emissions test you don't want to do this right now.

It's not due for an emmisions test anytime in the near future but how long can it take for any codes to clear up? When it resets the ECU will those systems not in the ready state cause the CEL to go on? I have an OBDLink Scan Tool that I could use to clear any fault ccdes. Would that be useful or recommended?

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Gary

1992 300E, 2006 E350 and 2006 C230 Sport

No, disconnecting the battery will not trigger the CEL (in fact it will clear it if it is on).

It's the same result as hooking up your OBD-II reader and clearing codes. Either one leaves the system in an "unready" state. If you do a good mix of driving, the systems should be reset in anywhere from a couple of days to a week.

The disconnect/code clear will cause the systems to go into "not ready". (They should all be "ready" right now.)

If you're interested, after you reconnect the battery and start the car, plug in your code reader and parse the menus. Depending on the reader and display, it should reflect the systems that are "not ready"; check the reader manual on that. Then you can check it again after a couple of days and see which ones still aren't "ready".

After all of this discussion, after you finish the brake job you'll think, "man, that was a piece of cake."

I have nothing relevant to add to this string. I just wanted to say how glad I am to have a simple old W124. Please, carry on.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles