Dragging rear brake, Pointy.

I noticed the other day that my rear disc around the outer rim was blue, I was like that looks cool...

when I rolled the bike out of the drive this morning I was like, this seems heavier than normal, shrugged it off and rode to work...

then when i got to work today the rear disc was smoking, no not a spliff, smoking hot!!! the rear brake has been engaged all the way to work.

Obviously I need to remove the caliper, remove the pads and try to free up the piston.

if there any specific lube or cleaner I need to buy? I don't want to do a full service / replace any seals etc I just want to free up the piston/calipers.

I have a 2011 sport with about 18k on the clock.

help please folks.

thanks

[Sid Squid]

Pointy has single piston, sliding caliper. May be dragging piston or slider not moving freely.
Remove caliper, support bracket sliding pins should move easily, if not remove and clean, RRG best for reassembly.
If piston stuck then seal grooves probably clogged up, remove piston and seals, scrupulously clean everything, ensure seal grooves are perfectly square and unobstructed. Even if you don't want them new seals would be my recommendation - if you're asking how brake work is done then with greatest respect I do not trust your ability to discern seal condition, they may be fine but the only certainty is new ones.

as I thought!
ok looks like i won't be rock climbing tonight and I will be servicing my brake caliper...
I'll get some RRG / brake cleaner / air duster etc to nurse it along until its proper service and brake fluid change.
will let you know how I get on.
thanks

[Sid Squid]

Brake cleaner isn't for cleaning calipers - it's a degreaser for friction surfaces; brake pads, brake discs and clutch friction parts.
It's expensive and not particularly good at cleaning crappy calipers, the best thing for calipers is cheapy supermarket own brand cream cleaner - I'm sure expensive stuff like Jif (or Waitrose OB if you're proper posh) would work just as well. There is no chemical help worth having for the seal grooves, scrape them out very carefully with a soft tool - do not gouge the aluminium of the caliper or it will be scrap.

When mine was doing that it was because the actual break pedal was sticking. My local garage striped the pedal and cleaned it and then it was good as new.

good to know, I'll check that too

[sputnik]

Depending on how bad it is I'm sure the wise advice would be not to ride it at all, but assuming you need to get home, do take care. Might even be worth seeing if you can retract the piston a little before setting off and keeping off the rear brake. Sticking pistons, knacked seals etc can cause heat to build up rapidly causing the wheel to lock (or at least slow down violently) with little warning - predictable unpleasantness may ensue! Arguably better at the back than the front, but not good at either end...

It's been like it for a couple of rides I suspect... I would like to ride it home and sort it. If I called the AA would they do anything do you think?

well to save my time and ensure I did not end up road kill I called the AA to release the rear brake so I can ride home safely.

i will take apart clean etc tonight. thanks all for your help and advice.

[JulesW]

Originally Posted by nikon70

rock climbing tonight

Hi Nikon, a fellow rock climber, whoop whoop! Brilliant sport innit. I don't do so much at the moment with work and stuff getting in the way but of all the things I've focussed on in life rock climbing has been hugely rewarding and bucket loads of scary fun.