Sticky brakes? it might be time to clean the caliper, not new ones

[YamahaFan]

Sorry - this is for disc brakes only (work for cages as well), and this is MY OWN EXPERIENCE (no I'm NOT a mechanic, I'm just good with observing the things I take apart)
If your brake's piston is not moving much when you squeeze it, and there is no leak, and you recently bled it then most likely you need to clean it.

WARNING: during the process do not damage the rubber that holds the piston unless you're in for new caliper. Also avoid grease on the brake disc and pads, if so clean them with certain cleaner.

- take the brake pads out
- take the caliper out (but leave the brake hose in tact)
- push/squeeze the brakes so that it'll push the piston(s) out. I actually took everything off once (including 2 sides of the caliper) and ended up putting them all back together so that I can get them out, so I don't recommend to try to take the pistons out by other means. If they are coming out unequally you might have to use C-clamps to hold the almost-out side to let the other side out too, then just use your hands to pull them out (DON'T use those pliers because they can damage the piston - one mark can doom the thing)
- take everything apart (hose and 2 caliper's sides - might have to attached it back to the frame so that it'll be easier for this job)
- clean the pistons with WD-40 or any cleaning material
- clean inside the caliper using a clean rag (since it's pretty clean anyway), make sure no dirt/sand gets inside, and make sure the rubber ring inside stays in its place - it's there to keep the grease in place.
- Time to put everything back: put fair amount of grease inside the rubber part that holds the piston, it's ok if a little gets deep inside the caliper - it should dissolve in brake fluid. Now that it's clean the piston should slide easily into the caliper. However putting the rubber on the piston is a bit tricky, require patience. I put one part of the circle on first, hold it with one hand, then use a flathead screw driver and run it around the piston.
- clean the sides of the caliper before putting them back together, make sure the rubber seals stay in the correct place.
- install the whole thing back to the bike, connect the brake hose, bleed it, voila!

Now, I might have missed something, or done something wrong with this, so post and let me and others know. I might be doing this on my truck so I can take pictures if requested, like I said - it's no different from cages.

Good luck with yours,

[Custom85VT]

Only to stress the liberal use of brake cleaner (spray) to remove any greasy/oily leftover from the job from the pad surfaces and rotor(s) before mounting caliper on disc and again when the job is finished. Any contaminants (brake fluid or even fingerprints) can ruin your whole job if left on.

[YamahaFan]

Only to stress the liberal use of brake cleaner (spray) to remove any greasy/oily leftover from the job from the pad surfaces and rotor(s) before mounting caliper on disc and again when the job is finished. Any contaminants (brake fluid or even fingerprints) can ruin your whole job if left on.

good catch, though when I do this the grease rarely get stuck in those places because I'm careful enough, but still need to look for them.
One thing I'm wondering though: would they be burned once you hit the brakes or would they do some sort of permanent damage on either the pads or discs?

I know I know the first time you hit the brakes with them on that's ABSOLUTELY not a good idea, that's why I was wondering, not intend to try :)

[Custom85VT]

Well even small things can lead to bigger problems down the road. A little contamination could lead to glazing, squeaking, then uneven wear or grabbing or pulling, etc. Yes it could just burn off but perhaps by then the damage is already done and perhaps compounding.

An ounce of prevention is worth a pound of cure and a stitch in time saves nine...and all. :D

I know that at least (more so) with cars by the time its all finish my hands are covered with crud and so is anything I have touched.

P.S. Feel free to delete all this banter to clean up your How-To. :o

[YamahaFan]

Nah it's all good, if you DID that I'm pretty sure others would too, so leave it there as a caution for others.

[YamahaFan]

One thing I'd like to add: whatever you do - DO NOT damage the rubber that wraps around the cylinder, or you'll end up buying a new caliper.

[Biker_Steve]

Only to stress the liberal use of brake cleaner (spray) to remove any greasy/oily leftover from the job from the pad surfaces and rotor(s) before mounting caliper on disc and again when the job is finished. Any contaminants (brake fluid or even fingerprints) can ruin your whole job if left on.

Great advice. Thanks

[SkinnyDave]

Ah jeez. I should have read this yesterday :(

I just tried "fixing" my front brakes (2 calipers)... They seized up completely the other day, totally out of the blue. I took everything apart to try to get those pistons out to clean the heaps of crud that were stuck in there, and the pistons WON'T MOVE! ... Compressed air wouldn't get them out, vice grips wouldn't pull them out, they wouldn't budge when i beat the hell out of them with a hammer... nothin... And then my hands were covered with hades and I was running out of daylight fast (no garage) .. i guess i should have left them off... but i put them back on... trying to get the pads back into the calipers greasy hands and all. I got a fair amount of junk between the pads and rotors i'm sure. Will it cause damage just by sitting there? Shoudl I go pull them off right now?? ... or should i just get some brake cleaner and go to town next chance i get?

and PS - how the heck do i deal with stuck pistons? :confused:

[lhurt]

Hi Dave,

A hammer and hydraulics don't go together. Neither do anger, frustration and good motorcycle maintenance.

If you don't know exactly what do to, take your time and move slowly. There are way more wrong ways to perform a task than right ones. And quite a few of the wrong methods can lead to expensive repairs.

Did you release the hydraulic pressure when you were trying to force the pistons to move? Yamaha fan is recommending using the hydraulic pressure to push the pistons out of the cylinder.

One thing you might try on the stuck pistons is a c-clamp. The pistons are most likely jammed at an angle after all the banging and pulling. If you can get the c-clamp to align perfectly, you can try to push the piston back into the caliper slightly to straighten it out.

Luke

[SkinnyDave]

Luke,

Thanks!

I wasn't all angry and aimless as I may have sounded. I just figured a hammer might release some stuck rust or something, after the recommendation from a shop to tap the calipers with a hammer to unstick them. guess i took it too far :p

I'll try a C clamp next. thank again.

[SkinnyDave]

Luke,

Thanks!

I wasn't all angry and aimless as I may have sounded. I just figured a hammer might release some stuck rust or something, after the recommendation from a shop to tap the calipers with a hammer to unstick them. guess i took it too far :p

I'll try a C clamp next. thank again.

[Custom85VT]

I'll try a C clamp next. thank again.

Do you have the cylinder off the bike? Or is everything still attached? I would recommend (if not yet) removing it and working on it at the bench. If not (as suggested) be sure to open up your bleeder so the pressure you’re applying has somewhere to go. And it should go without saying NO NOT go steel to steel with the C-clamp and your piston/cylinder walls! :eek:

[SkinnyDave]

Custom85 ... I have taken the calipers off.. meaning the pressure is gone from the system. After I discovered I couldn't get the pistons out, I tried reinstalling them and re-pressurizing the hydraulic system to try to "push" the pistons out with the fluid... but apparently I don't know how to do it, or something is REALLY clogging more than just the pistons.. because I couldn't get fluid down into the lines by pumping and messing with the bleed.

One strange thing I noticed is that even though brake fluid poured out when I unfastened the brake line bolts... the bleed nipple bolts were both dry and corroded when I took them out :( I even created my own vacuum system by connecting tubing to the bleed nipple, running that tube into a side hole in a plastic jug, and then using my hand and a vacuum cleaner to slowly introduce vacuum suction at the mouth of the jug, to draw some brake fluid down into the caliper and out the bleed (maybe I just don't understand what valves are involved in the brake system because this did absolutely nothing apart from totally collapsing the jug after a minute.. and yes the bleed bolt was open :p). this leads me to think something weird is going on inside the calipers and preventing brake fluid from filling up the internal chamber, leaving bubbles at the top by the bleed.. which then corroded the bleed bold and made it non-bleedable permanently. or something.

Any of this make sense or sound right?

[YamahaFan]

I think at this point you need to move the pistons, doesn't matter in or out. IF the pistons are already flushed with the caliper I have no idea, but if not use C-clamps to push it/them in by inserting something inside the piston and squeeze it in, NOT by much, just enough to move it, then try to get it out. I think hydraulic pressure is best since it doesn't require much patience and faster (putting the things back should be easy since I figure you must have taken it apart like a million times by now :))

[SkinnyDave]

OK I think I just realized what you guys mean with the C clamp. Do you mean aligning the clamp so that the screw part is pointing INTO the piston, and the stationary end is outside the caliper? At first i thought you just meant clamp sideways on the piston like a plumbing wrench onto a pipe. I thought "what good would that do??" ... But now I think I understand... by pushing the piston back into the caliper from its dead center, with the C clamp, I might be able to get it to straighten out and dislodge to the point where I could slide it out. Is that what you mean?

[YamahaFan]

OK I think I just realized what you guys mean with the C clamp. Do you mean aligning the clamp so that the screw part is pointing INTO the piston, and the stationary end is outside the caliper? At first i thought you just meant clamp sideways on the piston like a plumbing wrench onto a pipe. I thought "what good would that do??" ... But now I think I understand... by pushing the piston back into the caliper from its dead center, with the C clamp, I might be able to get it to straighten out and dislodge to the point where I could slide it out. Is that what you mean?

you got it :)

[Archangel]

I have used air pressure to push pistons out in the past but it can pose a danger the pistons can shoot out like a gun IE. point them in a safe direction and wrap the caliper with rags covering the piston opening to prevent damage to the pistons or your self and to contain the pistons undamaged.
It is unlikely if they are that stuck they will be any good after removal.
make sure you have on safty glases and Just hold a rubber tiped high pressure hose to the fluid inlet and hopefully bang out comes the piston.