Brake caliper overhaul questions

[Smokinapankake]

Chef,

Using the stock set-up. Splitter at the bottom triple clamp.

Colin,

Thanks for the links - Reading through them I suspect something is amiss at the master cylinder. There is no way it could be anywhere else.

Ed,

I doubt the pads are the root of the problem. Notice that the first bleed off locked my calipers. It's possible that the pistons might have gotten skewed in the bores due to uneven wear on the pads. But upon removal of the master cylinder and prying on the pistons, they slid back into the bores with little resistance. What I don't get is how the M/C relieves pressure when the lever is released. Both holes inside the reservoir are clear, yet nothing pumps or releases?

I may pull the brake lever off the Kat thou and try it just to see what happens....

[Smokinapankake]

So you may all label me a doubting Thomas. I have been through the whole system 3 times now, and for lack of anything suspicious, I've ordered new brake pads on the theory that the uneven wear on the old ones has caused the pistons to skew in their bores. If this doesn't solve it I don't know what will. Will keep you posted....

[chef1366]

Relieving pressure does not release the calipers. HMM Has to be binding pistons or calipers.
Take off the calipers (one at a time) and pull the brake lever and check out the travel of the pistons., They should be even, smooth and should also travel back a bit when releasing the lever.
Of course stop before the piston comes out of the bore.

[Smokinapankake]

So you can all rest easy knowing that brake pads solved the problem.
Put some new EBC HH compound pads in, pumped the lever a few times, and viola! Pistons retracting, lever building and then subsequently releasing pressure. A beautiful thing.

The moral of the story: GSR is THE place for the absolute most knowledgeable members who will bend over backwards to help. Thanks again guys, this makes probably bacon saved number 5 for you!

I would have fought that caliper problem for probably another month or more, never considering skewed pads to be the culprit.
Thanks!

[hillsy]

Glad to hear it worked out

[RJ]

Glad to hear you solved the problem. The one thing I would be cautious of is that when the new pads wear down to the same thickness that the old ones were at, you may wind up experiencing the same issue as the bores in the calipers may be worn in an egg-shaped fashion. This would allow the pistons to get cocked in the bores and not fully retract. Not trying to be a buzzkill or anything, it's just that changing pads can only affect so much of caliper functioning.

[Smokinapankake]

Maybe next time I bore gauge them....

[Nessism]

Glad to hear you solved the problem. The one thing I would be cautious of is that when the new pads wear down to the same thickness that the old ones were at, you may wind up experiencing the same issue as the bores in the calipers may be worn in an egg-shaped fashion. This would allow the pistons to get cocked in the bores and not fully retract. Not trying to be a buzzkill or anything, it's just that changing pads can only affect so much of caliper functioning.

I don't think there is anything to worry about. The caliper bores don't wear, even if the pistons are skewed slightly.

[Steve]

If the brake pads are worn unevenly and you have just replaced everything else with NEW, I think the pads are due, too.

So you can all rest easy knowing that brake pads solved the problem.
Put some new EBC HH compound pads in, pumped the lever a few times, and viola! Pistons retracting, lever building and then subsequently releasing pressure. A beautiful thing.

Thanks for the success report. I was just trying to suggest something that seemed obvious to me.

Too many times I have fussed over something saying "it just can't be ..." only to have someone else step up and suggest that very thing. Lo and behold, when I finally broke down and tried it, just to humor the other person, that's what fixed it. Sometimes it just takes another set of eyes on the problem.

.

[AOD]

Scuff up your front rotors for those new pads and be careful not to 'glaze' them by using the brakes too hard in the beginning.