need help with brake calipers

hello all, I'm rebuilding my brake calipers and need some help. its been 4 years since I've done it and need some help. there off of my 07 zx6 and the pistons won't come out
if possible give me a call I would appreciate it greatly.
602-578-5985

thank you in advance

 

never mind... the first race of the year (ccs) has been canceled... no rush now...

 

take the banjo bolt out, and give a blast of compressed air down the hole, be prepared to catch the flying piston tho

cheers.joe.

 

did that... only one comes out the other 3 don't move...

 

What I usually do is remove the pads, then lay a small wrench in the channel between the pistons (the space where the rotors normally sit up in), then pump the lever until all the pistons are all out, the wrench will hold the faster moving pistons in place until the slower moving ones get forced out. Once all the pistons in both calipers are all the way out and butted up agains the wrenches in each caliper, pull the wrenches out and hold the calipers over a pan and keep pumping until the first 1 or 2 pop out and start leaking fluid.....then unbolt the banjos and take the calipers off the bike. The pistons should all be pretty close to coming out like this and you don't have to rely on the compressed air to force them out so much. I can usually just take a cloth rag and cover the piston and wiggle it out carefully with a pair of needlenose pliers. Be very careful though because you don't want to scratch or deform a piston so just grasp and tug carefully. If you pushed the pistons all the way out via the brake lever as I described above it shouldn't take too much tugging to get them out.

If you want to be really crafty they make piston pliers with little pads that grab the piston from the inside and twist it out.

 

thanks bud, wish I had remembered that or asked before I took it off the bike... lol I jumped ahead of myself. what about when the pistons are out? the 2 seals for each piston, just pull them out and push the new ones in? I should know all of this I've done it before... I've had such a brain fart lately.

 

Yeah, once you yank the pistons out there will be a piston seal (thicker inner one) and a dust seal (thinner outer one) in each piston bore. Just pop them out with a very small thin flatblade screwdriver.

Obviously make sure you clean and dry the insides of the calipers very well, then coat the new seals with fresh brake fluid and pop them in, coat the pistons and inside the bores with fresh brake fluid too and pop them back in as well.

I see way too many people neglect giving their pistons a good thorough cleaning on a semi-regular basis, but that crud really accumulates in there and does just what you are seeing.....jams shit up.

When all of a sudden all 4 pistons in each caliper are once again moving smoothly at the same speed and applying even pressure all over the pads you'll think you did some kind of upgrade like better pads or something, lol.

 

thank you all for your help and advice! I've got them dis-assembled and cleaned... unfortunately I barley scratched one piston.... have to replace it now (god those piston pliers would have been awesome... lol definitely a good investment!) and thanks for the re-assembly tips! you guys are awesome.

one final question though... what do you torque the bolts to? (three that hold both halves together) I tried finding it in the service manual but didn't see it... might have missed so ill check again.

thanks a lot! ill buy yall a beer if we ever meet lol :up:

 

I would imagine they are pretty close, but the torque value for GSXR Tokicos is 16 ft/lbs

 

sweet that's what ill use if I can't find it, they were tight getting them broken loose but then again they are 3 years and 30,000 miles old.

 

While we're on the subject of caliper bolts (that hold the caliper inner/outer halves together), do you recommend using new bolts every rebuild? Brembo rebuild kits used to come with new bolts, IIRC.

 

Do you reuse the piston seals or order new ones? Where is a cheap place to order new if that's the route to go?

 

To answer the above two questions.

I've never replaced the bolts that hold the 2 caliper 1/2s together. I don't see why you would have to replace them. They are steel bolts holding together an aluminum caliper body and you only torque them down to 16 ft/lbs......they aren't stretching????


The proper procedure is of course to replace all the piston seals. Having said that I've dismantled, cleaned out and reassembled a few calipers with the same seals that came out of them. Have yet to have any leaking issues in doing so (assuming the seals weren't damanged or ripped) and the calipers obviously worked much better without all the caked on shit on the pistons and outer seals.

I just carefully wash them with some warm water and dishwashing soap and dry. I never clean them with any kind of solvent or brake cleaner. Most of the seal kits I've seen are actually a tad on the picey side. To do a rebuild you would need a total of 18 seals, 9 per front caliper.

 

Since I've never done this before but it's the off season...

If I split the calipers, can I just reach in yank the pistons out or do I need to do that before I take the calipers apart?

 

The "Tech" section/forum is actually below this one on the main page :up:

 

yeah I know... that's my bad I fucked that up lol

 

It depends on how stuck they are, but pushing them out as far as possible first will make your life a HELLL of alot easier. Otherwise you'll need to put a compressed air gun into one of the ports to create enough pressure to force them out, and the pistons will come flying out like bullets I shit you not, so you'd better have them pointed away from you but into something soft so they don't get hammered when they hit.