"Insufficient" Rear Brake

[fauxamish]

I just bought a 2000 400ex a few days ago and I was trying to fix some things while I waited for parts. I noticed that the rear brake does not work. The pedal goes all the way down until it hits the frame/footpeg, with no resistance or any build up of pressure. The calipers do not close though or even close a little. So, there is no back brake. I have a Clymer manual and determined that the brake was "insufficient" so I checked the reservoir and added fluid and tried bleeding the brake by loosening the bleed valve and depressing the pedal, but no brake fluid came out.

Any help with this would be great.

I have the opposite problem in the front. The pads drag sometimes, but then they will allow the rotor to spin freely for several revolutions then they drag again. And it is only when rotating forward. I tried to remove the caliper, but the pads would grip the rotor.

Thanks for any insights/help.

[fauxamish]

Could it be the master cylinder?

[nosliw]

i would just keep trying to bleed the back brake. it takes a while for the fluid to make its way down if the lines are full of air.
what i do is put the end of the brake line into a cup full of brake fluid and keep pumping and adding fluid until there are no bubbles. then i hook it up and pump/bleed until i've got good pressure. be patient.

unless something is sticking, disc brakes are self-adjusting. what you can do (if your concerned) is do a rebuild (follow your Clymers)

[madmax400ex]

Good Luck with the bleeding fauxamish, just did my brakes - front and back. Back pads went on without a snag, but i had to replace the bleeder valves and rebuild the front calipers. I must have spent a hour bleeding the front brakes and they were still weak. So i ended up buying a mityvac brake bleeder. haven't used it yet, been to busy. Let me know how yours turns out.

[bbender85]

bought my 400 with the rear brake removed, so my pads finally came in the mail and i put it on last night, and bled it. not sure how soft the pedal is supposed to be, but it seems to be working.

anyways, are there supposed to be crush washers on either side of the fitting on the ends of the lines? like where the flange bolt meets the fitting, and the fitting meets the caliper?

[BigBore24]

make sure your front caliper slide pins arent siezed up. i have a2000 also and someone had left the rubber plugs off letting water get in and sieze the pins. when i put on new pads they would lock the wheel up. on the rear i agree about bleeding. bleed them for a good 30 min. pumping and holding, if you still get no pressure id say the mc is bad

[madmax400ex]

Originally posted by bbender85
bought my 400 with the rear brake removed, so my pads finally came in the mail and i put it on last night, and bled it. not sure how soft the pedal is supposed to be, but it seems to be working.

anyways, are there supposed to be crush washers on either side of the fitting on the ends of the lines? like where the flange bolt meets the fitting, and the fitting meets the caliper?
yes - i tried to find a picture but couldn't find one on the internet, but what you said is right.

[bbender85]

yeah, found... item 20. crap, guess i need to order more parts.

[fauxamish]

Ok, thanks everyone. I bled the back brake for probably 6-7 minutes before any fluid cam out. Now I have decent pressure, enough to go for a ride this afternoon. I'm gonna tear the whole bike down in the next couple weeks to fix it cosmetically, and I will replace the pads and fix the front calipers. Thanks again