HELP! 250r 1984 atc Brake problem.

[xbenzx]

Ok fellas I have a problem with 250r 1984. The brakes on the front do not stop the bike right. You should be able to do a "stoppie" stand on the front wheel by locking the brakes. I did everything your already thinking of. I sanded the disc rotor, I put a new piston and seal and dust seal in the caliper. I rebuilt the master cylinder. I bled the front brakes 30 times liquid squirts out and then i closed the bleeder. I have tried different methods of bleeding like pumping them up then opening the bleeder. I have also tried slow pulls of the handle and then holding it in till the bleeder is closed. I have replaced the brake pads with the best money can buy. The only thing i can think of is doing a reverse bleed on the system . The piston on the master cylinder goes in a half an inch before it gets real tight. On my friends quad the piston is supertight at the beggining.

[Daddio]

I sounds like you still have some air stuck in there somewhere. I use a vacuum bleeder to bleed them.

[Dirtcrasher]

No, you didn't do everything

The bore of the caliper could be worn and the housing junk.

The bore of your master could be worn.

But, is that the issue?? I doubt it, doesn't help but pressure is pressure or it would leak, although a worn master can let fluid leak internally.......

Are you running the rubber stock 25yo hose?? 3Wheelers barely do a "stoppie" with all brand new parts..... Those rubber hoses don't allow the master to put full pressure to the caliper. Get a stainless braided hose and if your parts are old and worn and you have to do a "stoppie", get better parts

[toocheaptosmoke]

I agree with DC, my front brakes are just OK, only thing I believe wrong is a "soft" vintage brake line.