Stumped on Brakes

[Backslayer]

alright this is what I have done so far, Ive rebuilt the rear master cylinder and the rear caliper. Still no brakes wtf, Ive bleed that damn thing for hours both manual and, with a mighty vac with no success, Ive even borrowed a master cylinder off a 150f and couldn't get them to work, It will pump up and get hard but go down, the only thing I haven't replaced is the hose, can't see anything wrong with the hose, Could a soft spot cause this? although I can't see any. What would you do?

 

[IndyMX]

alright this is what I have done so far, Ive rebuilt the rear master cylinder and the rear caliper. Still no brakes wtf, Ive bleed that damn thing for hours both manual and, with a mighty vac with no success, Ive even borrowed a master cylinder off a 150f and couldn't get them to work, It will pump up and get hard but go down, the only thing I haven't replaced is the hose, can't see anything wrong with the hose, Could a soft spot cause this? although I can't see any. What would you do?

Well, if you've replaced everything else, and it's still not working for you, you could have a pin hole in the brake line. I'd replace it.

 

[Backslayer]

Thanks Indy, It's worth a try,

 

[Backslayer]

Alright I bought a new line, and got them bled, The Brake still feels spongy, The brake only gets hard at almost the bottom of its stroke, I raised the pedal a bit to compensate but still don't think its right, I noticed that the caliper has quite a bit of free play side to side, about a good 1/8th, and the piston will come and and take up the play, and when its almost out of stroke gets hard and when I let off the pedal the piston will go back in. So is there a way to take out some of the play in the caliper itself, that might be my problem,

 

[Beuford]

The piston only goes back in a hair unless something is pushing it in further than normal, in which case you use more stroke getting it back out to where it should be and then it starts to engage the brakes and gets firm.
Check to see if your roter is true, check the wheel bearings for play, excessively sloppy caliper mounts and last but not least make sure the caliper slider pins are moving smoothly.

 

[Ol'89r]

I noticed that the caliper has quite a bit of free play side to side, about a good 1/8th, and the piston will come and and take up the play, and when its almost out of stroke gets hard and when I let off the pedal the piston will go back in. QUOTE]


Behind your brake pad is a metal spring plate with a tab on it. This plate keeps tension on the pads and keeps them from making noise and helps keep them positioned in the caliper. If your brake pad is on the wrong side of the little metal tab it will keep the brake pad from seating squarely on the disc. It will hold the pad at a slight angle and results in a soft pedal.

Remove your brake pads and the metal plate and inspect the plate. Make sure the little tab is not bent and the brake pads are on the inside or disc side of the tab.

Hope that made sense.

 

[Backslayer]

I understand what you are all saying I will look Into all those options today, and let you know how it turned out

 

[mox69]

The rear brake on my '02 CR250 "disappeared" last time I was at the track. I thought it was the master cylinder or caliper or something along those lines. You could press it all the way to the floor, and maybe get a bit of stoppage. Felt very spongy as well.

I decided 1st to put a new set of pads on and voila they were fixed. The old pads were NOT worn down 100%, but about 70%. For whatever reason, they had worn past what the caliper could successfully compress. I think it has something to do with the fact that the inner pad doesn't really move. You didn't say if you had replaced the pads or not yet, but if they are more than 50% worn, I would start there.