Quck question, rebuilding my brake caliper

So i finally got around to buying a grease gun to pop out my piston. Wasn't as much clean up as i was expecting. The inside bore was nasty though, especially the single rubber piston ring.

I need to know if i can lube up that ring so that i can slide the piston into its bore. I dont believe i can do with without any oil but i need to know if the brake will still function properly if i do so.

Thank you



Edit: after doing some reading online, i found out i should use brake fluid to lube that bizatch up before putting it back in the bore.

Cant wait to ride my bike again. its sat for 2 months now

 

Just make sure you got the groove it sits in religiously clean and you're good to go. Slather everything with brake fluid when you're reassembling, and then wipe up the excess.

 

okay, first try. epic fail.

got the piston in about 2/3rds of the way in with my fingers and it just froze. I think the rubber finally got a hold of it.

so i had to bust out the grease gun again and pop the piston out.

without that rubber piece in there, the piston slides in effortlessly.

i did clean that groove to the best of my ability but ill have another go at it. I think ill just brake fluid the crap out of everything and try it once more.

thanks for the reply fitz. your expertise is always helpful

 

Piston has to go in DEAD STRAIGHT, even if everything is clean and seal is seated perfectly. If it "cocks" on you, at all, you're sunk. Ask me how I know. (Or don't, I'm sure you can guess.)

 

well i cleaned the hel| out of that thing and i still cant get the piston to go back inside.

Im starting to wonder if the seal might just be too big? i bought it from xj4ever and it seats in there pretty well. I can tell the bottom side of the seal is kinda protruding out though. tried to seat it as best as i could with no luck.

I read somewhere else that a guy uses brake caliper grease to lube up the components. I may try this method. If it fails, im off to a shop to have someone pop that sucker in there.

Tried about 10-15 times now. it only goes a quarter of the way in before it gets stuck. cant believe i managed 2/3rds the first time.


Piston doesn't look horrible


Not the best pictures, id say the bottom part of that seal comes out a millimeter past the bottom lip, only on one third of the caliper

 

Buy me an airplane ticket to Phoenix; I'll rebuild the brakes for you.

(I was born at Luke AFB.) It's too bloody cold in Michigan, I could use a break.

Yes, you can use brake caliper grease but VERY sparingly. Yamaha rebuild kits come with a little packet of magic pink grease, enough for about 10 calipers. Brake fluid should work though.

HOWEVER: IF your seal channel isn't 110% clean, then the seal "hole" isn't "round" and it ain't gonna work.

 

I just saw the pics afer I clicked "submit."

In the very bottom pic, it looks as though the seal has a "lump" in it. If so, channel not clean.

Also, get that anti-rattle spring out of there, and clean out all of the grease, etc. Once the piston's installed you won't be able to, and you do NOT want all that axle grease melting into your new brake.

Re: the piston. I see some pits. Are they where the seal will "ride" when reassembled with new pads? If so, it's gonna leak.

Sorry to be the curmudgeon, but it looks like you need to get back on cleaning that caliper some more.