I'm after a bit of advice/tips, My bike has been stood for about 4 weeks and yesterday I gave it a bit of a clean and noticed the rear brake is binding, I could just about rotate the wheel by hand but it was very stiff, It's due in for a service and MOT next weekend and I need to ride it a couple of miles to the garage. The wheel turns ok when put in gear on the paddock stand but the disc heats up very quickly. Short of stripping the calliper completely does anyone have any tips for freeing it up? I really don't want to be doing a complete strip down of it . A: Because the garage will be doing this as part of the service, B: Because I'm a bit of a numpty with these sort of things and C: It's fucking freezing and I don't have a garage to do it in. Any tips will be greatly appreciated.
you dont need to strip down, take caliper off remove brake pads pump lever till pistons come out a bit, clean round pistons to get crap off, push pistons back in,put in the pads ect and try that
Yes, you need to exercise the piston. Don't use WD40 or similar. These will swell the rubber seals and make matters worse. I use a mixture of Mrs C's tooth brush and the back of emery cloth to clean the brake dust and road grime from around the piston once the pads are out. Pump the pistons out and back, out and back cleaning them again and again. When your done and the piston is smooth, a good coat of copper slip around the piston helps stop the ingress of dirt and dust. But not on the pad lining of disc. My top tip. Do this in October, dislodging the summer dirt before the weather cools and contracts the ali caliper onto the steel pistons causing the clinging you are experiencing.
on my cb there is a caliper float that gets stuck like a twat took some prizing off last time and then re greased with copper grease might be worth checking that too
@Baldrick mine did the same, as Johnny and Cab said, clean round the piston, mine as just passed MOT yesterday brakes all fine, use plenty of copperslip should be fine.
if you use copperslip you want the minimal amount possible. i never use copperslip on sliders etc, thinking about it on bike brakes only ever use it on pad pins etc. your issue is probably caused by the pads sticking in the caliper itself.
I would normally bow to you on most things mechanical, but having worked bikes over winters for many tens of thousands of miles, gaitoring the gap between the piston and caliper and any slide ways with copper slip and replacing it each October works.
One metre of aluminium expands 0.000 022 1 metre for 1 deg C rise in temperature. It would have to be very very very fooking cold. A 20 degree difference would give contraction of 0.000442mm or less than half a micron. Also given that the piston will contract and has at least 12 micron clearance. Sorry Kev but your theory is bolloxs. The sticking will most likely be down to the fact it's outside, so moisture will be it's biggest enemy, any salts picked up off the road will expand with the damp, this includes what gets trapped under the seals.
It gets cold, the caliper sticks, clean and seal the crevicies and the problem does reoccur. Net result the same, whatever the cause. Although you cause does sound even more feasible. I remember when bikes had properly gaitored pistons. Bloody Gixxer riders.
copper slip is to heavy on sliders, stops them moving freely, the reason it's worked for you is the fact that it's been cleaned on a regular basis. if i file the metal edge on a pad i'll use a tiny smear on the exposed metal just to help it stop rusting, literally brush on and brush off just to leave a slight copper colour is enough. don't forget brake dust will stick to anything greasy.
i am tempted to throw an insult at you for being a pedantic twat but it's been a long day and i'm knackered!! so fuck off!!
Best tool I've ever bought for doing the piston clean and lube (or not lube, as you wish) Easy to rotate pistons and pull them out if you need to.. I'd also dismantle sliders and remove the crap / rust etc with wet and dry or similar and copper grease them. And the pad pins and rattle clips.. http://www.ebay.co.uk/itm/Sealey-Mo...189?pt=LH_DefaultDomain_3&hash=item56665dde15
....what Johnny said ! Plus Cabs toothbrush tip - pop off the caliper, use lots of brake cleaner and scrub / rinse - if you want, use some soapy water and a stiff brush ! The main thing is to get the grunge off - don't pop out the Pistons too much as they may get stuck -out if you put anything on the Pistons use red rubber grease but I've found copper slip is fine on the slider pins and a dab on the back of the pads - don't contaminate the pads or disc ( spray brake cleaner on the discs and wipe with a clean rag when finished ...
Do these work ok where you have opposing pistons (eg Radial Calipers) ?- mine have 4 pistons ( 2 opposing each side) - I was wondering how this tool might work there ? Cheers !
what johnny said... can pick up a couple of cans of brake and clutch cleaner really cheap, and as mentioned use the mrs toothbrush. i cleaned with soapy water first, then blasted all of that off with a liberal squirt of brake cleaner and left to dry. ive also used copperslip, but whether its correct to or not i cant say as im still a mechanical noob