After fitting new brake pads last time, got all the way to germany before noticing rear disc red hot.Stripped caliper checked everything was free; greased pins, pistons easy to push in, sliders working ok.Took it for a run and still red hot.Have since repeated the whole scenario three more times once with a friend whose quite knowledgeable to no avail.Since been to rumania and back problem still there.Have now done around 6000 miles on same pads.Going on previous form this is average wear rate for my bike fourth set pads 2004 1200 gs.What im not sure is has the disc always got hot from new but i only noticed it after fitting last set. Never checked heat of disc before then.Any advice on curing this problem.
Hot rear disc
- Thread starter tortoise
- Start date
Big Lee
Registered user
Is a hugger fitted?
Whats it like when the bike is on the centre stand, does the rear wheel spin freely or bind instantly?
When the bike is cold does the rear wheel turn slowly when the engine is started and the box is in neutral?
Are you accidently touching the rear brake lever with the toe of your boot?
Does the caliper, when attached to the bike properly, have a bit of play in it? It should do if you grab it and wiggle it from side to side a little as with only having pistons on one side it should pull itself over.
I found after fitting a hugger the brake line was twisting the caliper slightly so locking the brake on enough for it to drag all the time.
Whats it like when the bike is on the centre stand, does the rear wheel spin freely or bind instantly?
When the bike is cold does the rear wheel turn slowly when the engine is started and the box is in neutral?
Are you accidently touching the rear brake lever with the toe of your boot?
Does the caliper, when attached to the bike properly, have a bit of play in it? It should do if you grab it and wiggle it from side to side a little as with only having pistons on one side it should pull itself over.
I found after fitting a hugger the brake line was twisting the caliper slightly so locking the brake on enough for it to drag all the time.
Seconded
Yep same as Big Lee..........if its got a hugger it affects the rear caliper
TD
Yep same as Big Lee..........if its got a hugger it affects the rear caliper
TD
Air in the brake line expanding due to radiant heat from exhaust and applying a little braking ? (clutching at straws, sorry)
GS Chris
Registered user
Remedy?
There is a slight binding on my rear brake, but not sufficient to cause undue heat. The wheel used to turn when starting on the centre stand, but not now.
I suspected road/salt crud from Winter riding was causing the jam. Have stripped the caliper twice, and cleaned well, making sure of free movement etc. Re-assembled only to find problem persists.
However, I now believe I know the cause. Refitting the pin, there is a tendency to hit it all the way back in. But then after fitting the small R pin, it makes contact with the left pad, pushing it against the disc.
So tomorrow, I will whip off the mud guard again, and just tap the pin from the right ( or off-side), to make sure the R pin is as far to the left as possible.
Chris
There is a slight binding on my rear brake, but not sufficient to cause undue heat. The wheel used to turn when starting on the centre stand, but not now.
I suspected road/salt crud from Winter riding was causing the jam. Have stripped the caliper twice, and cleaned well, making sure of free movement etc. Re-assembled only to find problem persists.
However, I now believe I know the cause. Refitting the pin, there is a tendency to hit it all the way back in. But then after fitting the small R pin, it makes contact with the left pad, pushing it against the disc.
So tomorrow, I will whip off the mud guard again, and just tap the pin from the right ( or off-side), to make sure the R pin is as far to the left as possible.
Chris
the shepard
Registered user
had a similar problem with my 1200gs after fitting new ebc rear disc and pads. piston fully home and caliper slid across, inside pad tight fit and drag on disc .filed friction side of pad no more trouble.had a trip to go on following morning.a bit rough and ready, but as i said worked finefor the past 5000 miles.
bmwrich58
Registered user
If not a warped rotor,......I'd say more like the piston not retracting all the way back into the caliper.
Might be some rust or some other foreign crap behind the piston in the caliper.
When was the last time you bled the brake fluid? Brake fluid very hygroscopic(readily taking up and retaining moisture)...absorbs moisture/water in the line and then rust forms inside caliper preventing the piston from retracting all the way. Very common on autos.
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