Rear Brake Caliper Help...pretty please?..LOL!

[JINKSTER]

Yes folks..it's me..the legendary "Jinkster" requesting "REAR BRAKE CALIPER HELP"..as follows..this is about the 4th time i've changed...excuse me..attempted to change rear brake pads tonight...as last ride out i started to hear that dreaded steel on steel sound when applying the rear brake and the light scoring of my rear rotor confirmed it..as i refrained from any further use of the rear brake..so tonight on the way home from work i pick up a can of autozones best brake cleaner..pads were waiting for me at home as i nonchalantly figured..no problem..1/2 hour job at best..put Oren up on her rear stand..dropped the caliper..popped the cap..pull pins..drop the old pads out..douse the caliper with the brake cleaner..and?..lotsa black shid didnt come off..oh well..bikes 9 years old...where's my c-clamp..go to put the squeeze on the pistons to fit the new fat pads in and..ut-oh..how come these biotchs aint complying?..wouldnt compress the piston sleeves in far enough..dang..well?..pump the brake and squeeze'em together to give a good cleaning..one pumped out further than the other till they touched and the piston that pumped out the furthest looked like it was gonna fall out..so?.i popped it out with my hand and rapidly pushed it right back in as about 1/8th a teaspoon of brake fluid came following it out..which is the moment i sad to myself..you dumbazz..no sense doing anything foolish like refreshing my memory or reviewing instructions cause after all..i'm a freaking genius!

now it doesnt appear to be leaking any more fluid and think i got lucky as i know the seals are of a square cross-section but..i know for a fact that if i dont get that black crud off the pistons?..

1. I'm never gonna get them compressed in far enough and?..

2. If i do leave the black crud on'em they will start leakings in short order.

so..3 questions..

1. Would i be best off just going ahead and ordering a caliper rebuild kit?

and..

2. What's the best method/product to get that black crud off my pistons?

and?..

3. Since i'm apparently going old, senile and suffering an acute case of CRS?...did i forget anything in this process?..cause the last 3 times i changed rear pads it seemed rather simple. LOL!

T.I.A. & L8R, Bill.

 

[Blanca BusaLess]

I don't know Bill but I wonder if now since piston came out whether you'll have to bleed the brakes properly now?

I've also read here a couple times 'do not pump brakes while caliper is off'
Not sure why?

Hope you get it figured out quick.
Congrats on the 18 month badge.

 

[JINKSTER]

I don't know Bill but I wonder if now since piston came out whether you'll have to bleed the brakes properly now?

I've also read here a couple times 'do not pump brakes while caliper is off'
Not sure why?

Hope you get it figured out quick.
Congrats on the 18 month badge.

Yeah..i figured "bleeding" was a given since i lost some fluid..and yeah.."Dont pump'em with the caliper off" because of what just happened to me..like i said..it did almost push the piston completely out...it was cocked when i grabbed it..live and learn..and with me it's usually the hard way.

 

[HillbillyTom]

You can break the bleeder valve loose a bit and get the pistons to go back in sometimes, but it sounds like time for a rebuild and new fluid anyway.

 

[JINKSTER]

You can break the bleeder valve loose a bit and get the pistons to go back in sometimes, but it sounds like time for a rebuild and new fluid anyway.

Fluids fairly fresh..nice and clear..changed that about a year ago and havent put 4k miles on since..i live 8 miles from work and take the truck most times these days. LOL!

dang...i dont get out enough lately..lol..like i said..gett'in old.

 

[karnage]

they are real easy to rebuild.I tore mine down to send off to the powder coater.There is 2 seals per piston.

 

[labrocha]

I take out my big channel locks and squeeze firmly, the piston goes back flush in the caliper, the fluid works it's way back to the reservoir. No need to open the brakeline, and never apply brake with calipers apart unless you want the pistons on the ground.

 

[kml]

If it doesn't leak when the brake is applied it's a good bet the seal has reseated. A rebuild might be in order.

I cut a thin strip of VERY fine autobody wet and dry paper wrap it around the back side of the piston and give it a few quick pulls with brake cleaner to remove the crud that has collected on the piston before I push it back into the bore.

cheers
ken

 

[BusaWhipped]

If you went down to the steel backing on the pads, I'd pop the pistons out and inspect caliper bores. The piston wiggling as it extends out that far can damage the calipers. That can cause the pistons to hang and not compress all the way back in again.

 

[card16969]

If you went down that far on the pad it could be some of the binding compound that holds the pad to the metal plate that you have floating around on the piston. When you get low enough on the pad it gets hotter and smokes a little and drops the compound all over the place kind of like smoking a rear tire some how you wind up with rubber in weird places. Personally i would rebuild the caliper since you obviously use it while riding (i dont use my rear brake alot). Its cheap and easy and you could always have it powder coated and clean up everything around it. To me it would give me peace of mind knowing its done and done right.

 

[Ludicrous Speed]

I would take them apart and give them a good cleaning. No need to replace the seals if they are not leaking.

Check this thread I did, gives you a step by step:

https://www.hayabusa.org/forum/maintenance-do-yourself/129252-how-rebuild-your-calipers.html

 

[mjn]

Leave it alone.. It'll be good practice for you to quit using the rear brake..

Have you been filling the res up as time has gone on? Could it be there is no room in the res for the fluid in the calipers to go?

I'd try crackin' the bleeder first.

 

[JINKSTER]

Well?..thanks for the help folks...got home tonight and decided to try again...no luck..pistons wouldnt compress back in..gave a few pumps (just to see) and no doubt i'm gonna need some DOT4 which i searched my shelves for and didnt have any..and figured..alright..no sense screwing around...called up the local dealer parts dept to ask if they had any rebuild kits..dude said they'd hafta order but then questioned me why i would want such..explained the situation..he told me i probably got the pistons cocked..saying that even an inpercievable amount is enough to hang them..suggested i re-assy with the old pads and pump'em back down to square them back up and try again..i dunno..cause he also told me i need to take the res cap off to get'em to go back in that far..anyways..i dont have DOT4 and i'm fresh outta patience...also gotta meeting i need to be at tonight so..i'm tabling it for the evening and going out back to sip coffee and shoot my bow. LOL!

again...thanks for all the help and suggestions and L8R, Bill.

 

[jstorz]

Echoing what Ludicrous said... rebuilding the rear is super easy once it's off the bike. Take a look at the fiche/service manual, assuming your pistons are good (nothing metal ever touched the outside), you really only need a few really cheap seals (part #69100-32821 for Gen I, #69102-05880 for Gen II) and patience. Oh and Dot4, rags, and some Simple Green to clean up what you spill

The Gen II is a single piston design, but on Gen I you can unbolt and split the two halves of the caliper. Then you can use some compressed air on the hose bolt hole (Gen II) or where brake fluid moves between the two halves (Gen I) to eject the piston. Keep a big rag over it though, the piston and brake fluid can shoot out pretty quickly.

 

[kml]

You are trying to push the pistons back into the caliper bores and you haven't removed the reservoir cap?



cheers
ken