Brakes sticking W210

[coneybiller]

Not sure if I should post separate from my other thread but it is a different subject so here goes:

I've noticed that the brake pedal feels a bit notchy. I've had it where the brake pedal has not returned all the way and partially sticks on causing binding. It's called for me to flick the pedal up with my left foot which then allows it to the top once again. It doesn't do it all the time, but I had to make a longish trip up the motorway recently. I tried to apply the speed limiter which has been working fine (unlike cruise, but that's another thread). The engine would cut out and it was slowing down, even tho the accelerator was depressed. I gave up and carried on without it. Then the ABS/BAS lights came on and a brake lining warning popped up. I was a bit unsure as to what was going on so started to slow down (coasting) and started noticing a bad vibration, which was getting worse and worse and the car seemed to be loosing power! I thought I may have a puncture so pulled onto the hard shoulder. Upon coming to a gradual stop, I noticed the 2 front brakes were smoking like crazy! Looked around the car and found nothing physically wrong. Jumped back into the car and realised the brake pedal had been stuck down ever so slightly, causing the pads to get hotter and hotter eventually melting the wear sensors into the pads!!

Just wondered if anyone else had encountered a sticky brake pedal before? The return Spring seems good and strong, could it be servo or master cylinder related?? I've never heard of this before!
I've just learnt at the mo to keep checking the pedal, but I really need to get this sorted!!

 

[AMGeed]

If your car is pre 06 reg you don't have a master cylinder and servo as such. You have electronically controlled braking (SBC) which although extremely efficient, it needs disabling before working on the brakes. You could possibly have sticking piston(s) within your caliper for the brake to stay on. You may also have a faulty ABS/wheel sensor.

With the problems you describe, it really need to be diagnosed on a Mercedes Star which should help reveal the exact problem.
Have you a local Mercedes independent technician nearby as he should save you a lot of money compared to a main dealer?

 

[coneybiller]

Hi, thanks for the reply. It's a W210 so doesn't have SBC which was introduced on the W211. Just good ol ABS and a traditional master cylinder and servo setup. I've replaced the front brake pads the day after it happened, as the brake lining warning remained on the dash. The wear sensors had actually melted and molded themselves into the pads, so new sensors and pads were the only answer. The front callipers are nice and free and the Pistons pushed back fairly easily, so that's not the issue.

Thought I'd put the feelers out to see if anyone had the same/similar issues?

 

[coneybiller]

Just to add, it's a 2002 E320cdi estate.

 

[t2doc]

Did you ever get to the root of your problem as I have a similar fault?
I am going to try and replace the return spring first to see if that helps, however I think the problem will be with the servo unit?


Sent from my iPhone using Tapatalk

 

[the-dodge]

Did you ever get to the root of your problem as I have a similar fault?
I am going to try and replace the return spring first to see if that helps, however I think the problem will be with the servo unit?


Sent from my iPhone using Tapatalk

The problem is caused by the Electronic Brake Assist (BAS). The actuating rod which is mounted in the servo sticks in the "on" position. There is a black cylindrical unit that is located on the front of the servo case near the throttle switch control, under the bonnet. Check the harness connector to the solenoid and give the solenoid unit a light tap. This may solve your problem, but the solenoid is a replacement MB part.