Mercedes ML270 - Brake problem

[Manx Man]

I have a Mercedes ML270 2002. I have just had new pads fitted all round and new brake discs on the front by the local garage. For some reason, since they have been changed, the front brakes only are sticking on. The garage itself says they are not sure what it could be but they assure me that its not a problem with the fitting of the brake pads. They think it might be the brake servo. I used to be a mechanic a long time ago, and cannot understand it myself. Can anyone shed any light? If it is the servo, does anyone have one? Thanks in advance for your help. Neil

 

[ernieh]

If the brakes were not sticking on before the pads and discs were changed, they shouldn't be sticking on now! Like yourself, I would have thought it unlikely that the servo was at fault.

However, if they pushed the caliper pistons back without releasing the bleed nipples, it is possible that one of the seals on the master cylinder has been damaged due to the fluid being forced in the reverse direction. Just a suggestion as it happened to me in a previous life.......If releasing a bleed nipple now releases the brakes, then this is the problem.

Another possibility that comes to mind is if they used non-oe parts, the clearances might just be a bit tighter, in which case they should ease off in time. It really depends how bad the problem is.


Ernie

 

[knowlep]

Sticking front brake

Hi,
Did you ever solve this problem as I have a NSF caliper that sticks intermittently but not through fluid pressure as if I remove the wheel I can quite easily move the piston back using a flat blade screwdriver with the caliper and pads all still in place.
It's really odd as the other 3 brakes don't stick.
Paul

 

[knowlep]

Sticking brakes after pad change ML270 Cdi

ML270 Cdi 2001
Just to let you all know some original caliper pistons have a coating which deteriorates over time so when you push them back to change the pads they can stick in the bore and hold the new pads against the disc enough to smoke them well hot. They seem to be quite free and working normally when you push the pistons back but they DO stick in normal use.
Not the garages fault or the person who changes the pads unless you are aware of this issue with these calipers. I found out the hard way. It's new caliper time unless you want to try and source the bits and rebuild them yourself.
The rear calipers don't seen to suffer this issue (yet) and I've changed pads a couple of times.

 

[Man]

I have a Mercedes ML270 2002. I have just had new pads fitted all round and new brake discs on the front by the local garage. For some reason, since they have been changed, the front brakes only are sticking on. The garage itself says they are not sure what it could be but they assure me that its not a problem with the fitting of the brake pads. They think it might be the brake servo. I used to be a mechanic a long time ago, and cannot understand it myself. Can anyone shed any light? If it is the servo, does anyone have one? Thanks in advance for your help. Neil

 

[Man]

I have had the same problems after fitting new brake pads and I have found the fault. The brake pistons ''grow''. The last part to enter the caliper when you push them back has increased in diameter by 004'' to 005''. I machined them back to the correct diameter and the problem was fixed.
I can see I have been a bit late in posting this reply but it might help somebody. Mike.