Loosing front brakes?!?!

[Sjorge450R]

I just put my R back together and i was out riding today. I just put new pads on the front too. Like today i was riding and then i went to grab the front breaks and there was nothing there, I just crushed my hand with the lever. I had to pump it a few times to get pressure. This happened a good 5 times within a hour. What could be wrong?

[Moto92]

did you open up any of the lines to allow air to get into the system. if so then that would be the problem. you need to bleed them and then after one ride bleed them again because you will work down any air you didnt get before. i never could get mine right so i went to autozone and bought a hand vaccum pump, works great so much easier. just make sure you keep the reservoir filled up because it will go down fast then youll just suck in a big air bubble.

[Sjorge450R]

Originally posted by Moto92
did you open up any of the lines to allow air to get into the system. if so then that would be the problem. you need to bleed them and then after one ride bleed them again because you will work down any air you didnt get before. i never could get mine right so i went to autozone and bought a hand vaccum pump, works great so much easier. just make sure you keep the reservoir filled up because it will go down fast then youll just suck in a big air bubble.

nope didnt touch any lines. I had this problem slightly before my rebuild. There would be time in races where i would havce to pump the lever to get anything . A few times i almost crashed. Maybe the fluid needs changing?

[IHScoutguy]

i know on some fast cars, or if you ride the brakes alot it's possible to get the rotors and calipers so hot the fluid boils, i doubt it but ya never know. i'd try bleeding it after a few rides and see if it clears up. if it's not leaking fluid it sounds like a bad master cylinder.

-Jon

[bloodmoney23]

they are right on the dot. first thing u need to do is bleed the brakes. it takes a good minute and best thing to do is get the bleeder kit. if it still does it after they are bled then your master cylinder is jacked up. hard to do but possible. my guess is you have a leak where air can get in somewhere in the system. anytime you open a brake line you need to bleed.

Are your rotors bent? That will make you have to pump the brakes. A bent rotor will push the piston in further than it is supposed to be. That will make you have to pump the brakes to move it that far.

If not go buy a vacuum pump and bleed them.

[Sjorge450R]

Originally posted by TRX450R_Racer
Are your rotors bent? That will make you have to pump the brakes. A bent rotor will push the piston in further than it is supposed to be. That will make you have to pump the brakes to move it that far.

If not go buy a vacuum pump and bleed them.

that crossed my mind this afternoon

but they arent. I checked. See the brakes work flawlessly when i dont have to pump them...... arg!!!! I think i am going to flush the system and start from scratch... lol

[300ex mxracer]

Originally posted by TRX450R_Racer
Are your rotors bent? That will make you have to pump the brakes. A bent rotor will push the piston in further than it is supposed to be. That will make you have to pump the brakes to move it that far.

If not go buy a vacuum pump and bleed them.

I had this problem last year at loretta Lynns. It happened in Saturday morning practice so i had to run both motos pumping the brake lever:grr: Use a straight-edge on the rotors because it wasnt bend enough to see but the straight-edge found it.

[300ex_#387]

Your master cylinder might also need rebuilt. Back when I had my 300 my master cylinder needed rebuilt, and I had to pump the lever to get the brakes to work.

You can order an OEM kit to rebuild it yourself. It is very simple to do.

[IOWAracer]

Hadthe same problem at my race saturday bike Is BRAND new only two weeks old lol and still did it idk i wen to the pits and bled them and got back into the woods and they were fine....

BB

[Scro]

You're not running Houser arms by chance, are you?