Rear disc binding

Wardy

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Hi gents, does anyone know the thickness of the rear disc please? I ask this as on a trip last year had over heating issues with rear brake, previous owner fitted new disc.
However I've fitted a good used caliper, new pads, bled brake, but it's still binding a touch. Previous owner had fitted a new disc, measures 5mm. Is this correct? Thanks in advance steve.
 
The BMW REPROM states : Brake disc thickness rear when new 5.0 mm , wear limit min 4.5 mm

However the brand new and unused Brembo rear disc I have just bought is only 4.2mm thick and it has stamped on it minimum thicnkess is 3.5mm

So not sure if that helps you

Did you strip the used caliper and clean the piston , seal grooves and the seals themselves and then assemble with red rubber grease to ensure you don't have a sticky piston ?
 
Thanks for reply John. Did check the caliper over, that's why can't figure i
 
Touched wrong button......It out. The only thing not changed is disc. I'll strip caliper down again and double check . Cheers Steve.
 
Have you tried cracking the bleed screw when pushing back the piston?
 
Hi smug, no Havnt tried that,but will attack it when get home from work. Cheers Steve
 
Yep peddles got play in it deano. New pads have come with thin stainless backs, think they might be anti squeal thingys, going to try it without them. Fingers crossed.
 
My money is on either a sticking piston in the caliper or in the master cylinder......


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Quick up date after a real hectic day, checked the caliper once again all looks good, cracked open the bleed nipple, took a bit of fluid out of reservoir and it seems better, not perfect, still binding but disepates when left for 30 seconds.
Just another thought, but these pads seem quite thick, you can only see about 1mm of piston, doesn't seem right. I'll take those anti squeal plates out, but maybe these pads are to thick ? Should have more time over the weekend.
 
Wardy said:
Quick up date after a real hectic day, checked the caliper once again all looks good, cracked open the bleed nipple, took a bit of fluid out of reservoir and it seems better, not perfect, still binding but disepates when left for 30 seconds.
Just another thought, but these pads seem quite thick, you can only see about 1mm of piston, doesn't seem right. I'll take those anti squeal plates out, but maybe these pads are to thick ? Should have more time over the weekend.
Click to expand...

If its easing off after 30 seconds that would indicate a sticking piston - have you checked the master cylinder ?
 
whilst i don't have a 650 , my 1150 did wierd things , brake coming on, on it's own , sticking , 50 yds later free's off , not touching it it would come on. did everything except master. changed master , problem gone. no rhyme or reason ....and i'm a bike mechanic.
 
Havnt looked at master cylinder. Never attempted this, is it a easy doable job ? On the caliper piston, after fitting new pads, should you be able to see the piston ?
 
Wardy said:
Havnt looked at master cylinder. Never attempted this, is it a easy doable job ? On the caliper piston, after fitting new pads, should you be able to see the piston ?
Click to expand...

I seem to remember the piston will go all the way into the caliper so you will see very little of it

Master cylinder rebuild is quite straightforward just a circlip and a couple of seals . I may even have a a spare complete master cylinder if your stuck

I think you use a KTM rebuild kit as BMW do not sell one - I'll do a bit digging and get back to you
 
Thanks John, I'll look into that, as you say, maybe worth my while just to change the master cylinder. Cheers Steve. Ps. Anyone know the thickness of new pair of rear pads. Process of elimination.
 
The new rear Brembo pads I have just fitted are 10mm total thickness per pad (friction material and metal backing plate)
I also have the anti squeal shims fitted which will add a little more thickness
 
Thanks john, bet mine are the same. Will check tomorrow. Cheers
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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