Mercedes CLA Forum banner

21 - 28 of 28 Posts

·
Registered
Joined
·
9,959 Posts
Has anyone looked at the rain/wet sensor feature? This is supposed to sense when it's raining and bring the pads in closer for quicker response in bad weather. Is this part of the sticking problem mentioned or is there something special the service dept. should be doing during brake jobs as these cars age?
Yeah think this the same as the moisture sensing system I was wondering about ... if it keeps thinking its wet more often than not then the pads will be scuffed all the time
Might have to see the sensor signal level specs and check that against actual data
Time to poke around
 

·
Registered
Joined
·
9,959 Posts
well I showed him the pictures and he asked first if your an aggressive driver? He then said either a brake line is getting clogged or the caliper is sticking. Either way the only way to find remedy is to replace everything and see wear after new parts are installed. But he was suggesting checking your brake lines first to see the color of the fluid.
Thank you again for the effort.

Geee if I am aggressive then the common folks are absolute monsters
Hardly ever use the brakes and when used they are feathered to a stop
But yes I was wondering why my rotors/pads are showing signs of overheating (that blue/grey surfacing)
If a line is clogged then have to examine how that may affect all 4 corners
Fluid is due for its 24~36 month flush but has been the same color since last replacement and moisture is still less than 1%
All 4 caliper pin sets are indeed due for clean and new lube soon so perhaps all pins are starting to stick a little
*
Just a thought ... could it be a bad batch of pad material such that the composition is varying with wear down?
 

·
Registered
Joined
·
1,507 Posts
he said that the caliper o ring might have unseated and its not fully depressing back into the caliper allowing the brake to rub more then the spec desired from Mercedes. that was his shot in the dark and he also said it would be much less of a headache to just replace fluid or a line then mess with the o ring problem. Im going to drop my car off at the brake guy today ill poke his brain a bit too.
 

·
Registered
Joined
·
9,959 Posts
O I C
Well when I yank things off I will peek at the piston seals ... hopefully wont have to unseat and replace ... yikes
Though with no pressure at nominal operating temperature the only thing pushing back against the piston would be incidental mechanical movement during drives (presuming pads and pins not sticking)
Goes right back to cleaning and lubeing
 

·
Registered
Joined
·
1,507 Posts
O I C
Well when I yank things off I will peek at the piston seals ... hopefully wont have to unseat and replace ... yikes
Though with no pressure at nominal operating temperature the only thing pushing back against the piston would be incidental mechanical movement during drives (presuming pads and pins not sticking)
Goes right back to cleaning and lubeing
Yea he went into detail about how the rotor allows for a minimal amount of play to spec in order for the piston to be pushed back into the caliper as the pad will always have a small amount of contact with the rotor at all times. I probably should have just recorded everything he was saying.
 

·
Registered
Joined
·
1,507 Posts
Oh thats OK ... gives us something to chew on
My other buddy said the same thing sticky caliper. Just need to keep tabs on it. If it begins to happen to more people it might warrant a tsb.
 

·
Registered
Joined
·
9,959 Posts
Well I think they can skate out of that one by claiming brakes not serviced often enough ... the renewal of caliper pin lube comes with more frequent inspections
 
21 - 28 of 28 Posts
Top