BLOOMIN' BRAKES!!!

DAMN IT!

Got a set of braided brake hoses to fit to my ZX7R at the Ally Pally show - have at last got round to getting them fitted and at the same time, decided to strip down clean & rebuild the calipers...

Rear went along fine with no dramas...

The front is somewhat more of an issue!

Removed one caliper, took out the pads and pumped a little on the lever to get the calipers to move... Only 3 moved freely, one moved nicely after a little more effort. There are however, two pistons that will not move!

Does anyone have any suggestions!!??

[northwind]

Yup... Get them out, and new seals. Maybe new pots if they're damaged or marked. Sorry.

[jambo]

put a thick spanner or similar down the centre of the caliper and keep pumping, when the moving pistons hit it they will stop and the 2 seized pistons become the point of least resistance in the hydralic system and will move out.

[Scoobs]

remove the pads and put a block of wood in between the pistons that move freely. Then pump the lever some more. The hydraulics pressure should get the others moving. Get a cotton wool bud and soak the seals around the non moving pistons will a little brake fluid first. Don't get any fluid on paintwork or pads.

[Scoobs]

Originally Posted by northwind

Yup... Get them out, and new seals. Maybe new pots if they're damaged or marked. Sorry.

Ultimately, this is the best answer.

[rictus01]

Originally Posted by jambo

put a thick spanner or similar down the centre of the caliper and keep pumping, when the moving pistons hit it they will stop and the 2 seized pistons become the point of least resistance in the hydralic system and will move out.

see he doesn't just turn Kawasakis into furniture

[northwind]

Luckily, someone was on hand with the answer, all I had to offer was negativity One good trick is plaster-bolts- the ones that expand when you tighten them up. Stick one in the pot, tighten it down so the butterflies stick against the wall, tighten as much as you can, pull out.

[jambo]

Originally Posted by rictus01

see he doesn't just turn Kawasakis into furniture

Oh no, Brakes I'm well up on now
Plus I had the same on mine a few weeks back!

If they really won't move dump the whole caliper in a bucket of hot water (tap hot is fine) if you prop the bucket up on a box or similar you can leave it attached to the brake hose. In 1 minutes try again and you may find it more complient! A toothbrush and external circlip lpiers then let you clean up caliper and pistons with hot water and grease them before they go back in.

Please note, all above advice handed to me by Sid Squid, tested and found to be dead good

[timwilky]

I have found that small G clamps are great for holding the moving pistons in place whilst the hydraulics then have to get to work on the seized ones.

Warning also apply loose clamps to the siezed pistons, the purpose being to stop the damm thing shooting out once pressure becomes sufficient to shift the siezed piston.

The clamps do not need to be tight. Their purpose is simply to stop the free pistons from popping out.

If however when the pistons do eventually move you find they have dragged seals there is nothing for it, the damm things have to come out, clean up new seals and bleed

Thenks for the replies guys!

Found a spanner of just the right size to fit inside the caliper...

Squeezed & squeezed and eventually (after about the 4th squeeze!) they popped out, quite quickly, one by one! Just hope they move freely and don't need me to lavish more time & money on them with new seals!

That's enough for today - they're gonna sit there with a spanner between their jaws, hanging from the brake hose overnight as I'm off for food and then to a mate's for beer and frivolity!

I wonder if the other caliper will be the same tomorrow!

Oh - and special thanks to Jambo for giving me the 'heads up' on the fact that this will probably have happened and to sort it now rather than later!!