Signs of rear brake binding or is this normal?

[FatBob]

I noticed recently that the pads on my rear brake are worn unevenly - this might have happened a while ago before the last MOT when I was told that the rear brake was binding a bit. It should have been fixed then but maybe the problem has come back.

I took the caliper off, put some grease on the sliders, everthing seemed to be moving OK as far as I could tell - never tried fiddling with the brakes before so I don't really know what to expect. Pistons didn't seem to be stuck as I managed to push them back in with my fingers.

I put everything back together and went for a test ride. I didn't use the brake much but when I got back the rear disc was quite hot and the front barely warm. On the centre stand the rear wheel spins OK but not as easily as the front so I guess the brakes are binding a little. The question is, is this normal or do I need to get a garage to look at it? Seems like the design of the brakes is more likely to cause this on the back than the front.

I am preparing for the onslaught for asking such a dumb question...

 

[Deleted account 190920001]

Do you have ABS or not? ABS brakes are linked so only using the front brake would still operate the back. If its none ABS and its still heating with no use then yes I would say the brake is sticking a bit. A strip and clean will sort it out.

 

[Paul G (BHT)]

A couple of things.... firstly, the rear wheel will be harder to spin than the front due to the fact that the shaft is being spun too.

Secondly, the amount of riders I see riding along with their toes resting on the rear brake lever is frighting are you 100% you're not one of these? Doing so will inevitably cause the disc to get hot.

 

[Wapping]

........ firstly, the rear wheel will be harder to spin than the front due to the fact that the shaft is being spun too.

...along with a bloody large and heavy tyre.

 

[tw99]

I put everything back together and went for a test ride. I didn't use the brake much but when I got back the rear disc was quite hot and the front barely warm. On the centre stand the rear wheel spins OK but not as easily as the front so I guess the brakes are binding a little. The question is, is this normal or do I need to get a garage to look at it? Seems like the design of the brakes is more likely to cause this on the back than the front.

I am preparing for the onslaught for asking such a dumb question...

I haven't tested whether mine is the same, but depending on how far you rode, wouldn't you get a bit of heatsoak from the final drive into the rear disc, whereas the front brakes just have pretty effective air cooling.

 

[JohnnyBoxer]

I think on a 12GS it is normal for the rear pads to wear unevenly, I think it is down to rear caliper design and specific to this model

Do a search, plenty of posts here

 

[Pukmeister]

The guide pins and single piston design means the caliper flexes slightly in use causing side wear in the bore of the guide pin hole. It's typical, both my 1200s have had uneven rear pad wear and slight binding.

 

[OldCroc]

As far as I am aware BMW try and compensate for the expected uneven wear as the new pads are different thicknesses. Therefore once worn they should both be similar thickness. If memory serves it is the piston side that is slightly thicker (fwiw)
OldCroc

 

[FatBob]

Do you have ABS or not? ABS brakes are linked so only using the front brake would still operate the back.

Yes its is ABS. I think most of my braking effort ends up being on the back because of the way the ABS distributes the effort, most of my braking being light. My rear pads wore out before the front ones even when the bike was new. Unless of course the brakes were always binding...

the amount of riders I see riding along with their toes resting on the rear brake lever is frighting are you 100% you're not one of these?

Pretty sure i don't fall into this category although I have never really thought about it. I find the rear brake is so far below my foot I have to stretch to put any real pressure on it so its unlikely my foot is anywhere near it normally.

I guess i could take the rear pads out and see if the wheel spins any easier, then i will have better idea of whether the brakes are binding or its just friction elsewhere. Assuming the brakes make no difference is it safe to ignore the hot disc? Seems like there is some unnecessary friction somewhere which might be wasting fuel if nothing else?

BTW its a 2008 GSA with about 30,000 on the clock.

 

[Steptoe]

I guess i could take the rear pads out and see if the wheel spins any easier,.

No need to take the pads out. Just push on the caliper with your foot and the caliper will spread open and you'll have plenty of room between the pads and disc .

Remember to pump the rear brake pedal when you've finished.

 

[JohnnyBoxer]

Unless of course the brakes were always binding...



I guess i could take the rear pads out and see if the wheel spins any easier, then i will have better idea of whether the brakes are binding

Read posts 6 & 7 again..................

 

[cookie]

couple of things:

the rubber covers on the slider pin tend to push one brake pad against the disc constantly.

IIRC the pads are different thicknesses when new.

 

[Deleted account 190920001]

Sounds normal to me since you have ABS. Back disk will always get hotter since there isn't much wind round it. They seem to wear the back pads out quickly as well. Unless you feel and hear a decent bit of friction I would leave well alone.

 

[Pukmeister]

Do as Steptoe says and see how freely it spins, then apply and release the rear brake and try spinning it again....You'll soon work the caliper issue out for yourself. Not ideal having cantilevered forces causing a bending moment through a sliding caliper rather than it acting like a simply supported style beam with a support at either end, it's bad engineering yet again by the Germans who could do better.