BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

on 2002 R1150R ABS

Just changed out the front brake pads.

1. The right side set of pads seems to have worn much faster than the left side. Is this normal?

2. Now that they are changed, when I rotate the front wheel there seems to be a lot of friction from the pads on the rotor. The pads themselves are actually touching the rotor. Is this normal and will wear in, or is something wrong?

3. When I pushed in the pistons to replace the pads, it looks like a little bit of brake fluid (maybe an ounce) leaked out somewhere towards the rear wheel.



I am an amateur wrench and probably know just enough to get myself into serious trouble. Any answers or advice would be appreciated.

M

1. The RHS pistons are maybe sticking in their cylinders more than the LHS (see answer #2 below also).

2. Also possibly caused by sticking pistons.

3. This is normal when new pads are fitted, usually pays to drain a little fluid beforehand. Pushing in the pistons forces the fluid back.

Did you notice any corrosion (or other crud) on the pistons when you were down there?

didn't see any corrosion. and yes, the overflow came from by the foot peg and it looked clean.


So what can I do about the piston sticking?

You would need to clean up the Pistons. Normally (on a non-ABS bike) you would just use the hydraulic fluid to pump them out of the caliper, clean them up, replace them, renew the fluid and bleed the system. On our ABS bikes, the bleeding procedure is more complicated and I would prefer you wait until someone more knowledgeable gets in on this thread. I know from a friend with an early R1200GS (with a similar power-ABS system like ours) that it is possible but, if you are an amateur wrencher like you said, don't go diving in and try this. Anyone care to comment? Just as a PS...if the binding pads are not causing the wheel to drag too much, just leave all alone and let the new pads wear down until it all loosens up.

The heavy front wheel drag is caused by caliper pistons not extending equally the first time, forcing the floating disk to one side, left or right within it's allowed range of axial movement. Even all new parts can cause this situation because the piston force required to push the disk off center is very small. If you start with extended, cleaned pistons and push-back the caliper pistons to repeatedly push out old DOT4 fluid (brake lever held partially squeezed to prevent fluid back-flow) before the new pads are installed, the chances the pistons will properly center are better. What forces them to center quicker is a couple tire squealing squeezes of the front brake lever at road speed.

You should never push back dirty or uncleaned pistons! That can and will force brake dust particles into and past the caliper piston seals, further increasing the certainty of brake drag. That means shorter pad life and at worst, short lived, overheated, discolored rotor(s).

Thanks for that Cyclerob, perfectly explained.