More 400ex brake problems, please HELP!

[nikejoe]

I've got an 01 400ex that eats rear brakes. I got a new rotor and also checked the foot brake is not hanging up making it drag. The piston that pushes on the pad is hanging up though. When I go to change pads I can't get it back on the rotor. I have usead a c-clamp to push the piston in but it is still very hard to get the new pads on. Then they only seem to last for a couple hour ride. Obviously something is hanging that piston up. The other weird thing is when I was checking the pedal to make sure it was loose. I was basically pumping the brakes up and down. When I went to check my brake fluid it was showing low. But it was fine last time I checked it. I know nothing about how they really work or bleeding them or anything. I just know I need to get mine figured out. ANy ideas on what's going on here??? and more importantly and fixes? Thanks

[nikejoe]

Anyone got any ideas. I did a search and didn't come up with anything. Thanks Again!

[44oEX]

take you park brake off and put in a block off plate. it sould fix the problem. you disk could be bent also

[nikejoe]

Sorry I forgot to mention the parking brake is off has been since I've had it. And it does have Block off on it. Any other ideas?

[44oEX]

check you disk. or the piston might seeze and not back off after you put the brakes.

lift the back end up and hit the brakes. then check if the rear wheels turn freely after you release the brakes.

[aviator4]

Is one pad wearing more than the other? I sounds like you have have a ceased pistong in the brake caliper. This would cause the caliper to drag and wear the pads too quickly.

If you're going through an entire set of pads in a coupe hours worth of rides, you're destroying a rotor every time as well because of heat buildup. You should replace that rotor and figure our the brake issue BEFORE you ride again, or you will have to replace the rotor again.

Disconnect the pedal from the cylinder and make sure you can easily move it up and down and it doesn't rub on anything (like aftermarket pegs) If it's difficult to move or won't return under the return springs power, there's your problem. Pull the pedal and make sure the bushing is clean - NO GREASE. When you replace the cotter pin, make sure it's not dragging on the frame of the bike or you will have a rust spot.

Are you absolutley SURE that you're not dragging your foot on the brake pedal when you ride? ABSOLUTLEY sure? You'd be surprised how many riders do this and do realize it. .

Give that a try and lemme know

[nikejoe]

Yeah they stick! The disk is brand new! I can't even get the new pads on very easy at all. So what do I do with a stuck piston? It will come out more when the brakes are applied and seems like some pressure is released when brake is released, but it always has some pressure on it. How can I fix this?

[44oEX]

maybe rebuild the caliper or get a new one

[nikejoe]

Aviator, my rotor is brand new now I have not rode on it and am trying to fix this before I ride on it and tear it up. It is not in the pedal and no I do not have my foot on the pedal. The brakes are dragging with the pedal up and noone on it you can tell they are slightly on. Any other ideas?

[44oEX]

your piston is not backing up like it sould. I say that is you problem

[JDiablo]

you probably need your caliper rebuilt,if you do the back one i suggest doing the fronts as well so you don't have to do it another time in the long run

[colt45er]

4oo's have had rear brake problems since 99. they eat rear brake pads and their was a recall awhile ago on the prob. . if your piston in your caliper is hanging then that very well could be your prob. take the caliper apart and clean it all as well as you can an get the piston moving smoothly. . thats the best i can give you.. later days man

[Rich250RRacer]

Get the piston out of the caliper, and remove the seals. Use a small dental pick and scrape the grooves clean. The aluminum tends to oxidize and this builds up and pushes against the rubber seals which then puts pressure on the piston and does not let it return properly. After you get it completely clean, spray it out with brake clean, install new seals and coat them with brake fluid. Make sure the piston has no grooves or scratches and reinstall it. If you've cleaned the caliper properly, the piston should push in with just a little finger pressure.

[nikejoe]

Thanks Rich, I got it completely apart last night. Everything cleaned up pretty good. Gto new seals for it and I will put it back together tonight. Thanks for the help guys!

[nikejoe]

Finally got it all back together and got the brakes bleed. Thanks for your help! Seems alot smoother now. I put all new o-rings and bushings in there, basically everything rubber I replaced. Very cheap fix, Cost me under $10. Cleaned everything else up really well and put it all back together. I was a little intimidated when I started this because I knew abosolutely nothing about how they worked, fyi it's pretty simple!!! Thanks to everyone who helped with different ideas!!! You guys are great!

[44oEX]

glad to see you got it to work good.:cool: