Front brake isn't engaging...

[nisus1]

I tried bleeding the front brake, but when you pump the brake it barely moves any fluid.  The lever moves with absolutely no resistance.  I'm thinking that it is the PISTON/CUP SET, which is what pumps the fluid from the cylinder.  My brake lines seem to be perfectly intact and the rest of the master cylinder is perfect.  It just won't pump any damn fluid.

Does this sound right?  Should i try replacing only the piston?  Has anyone done this and if so, how hard is this to do?

Thanks in advance for any wisdom.

[newtonent]

Sounds like you have air in the line. Some times they are hard to bleed. Take a rubber hose the size of the bleeder valve,put it on a plastic squeeze bottle(like a ketchup bottle at the restaurant) fill the bottle full of brake fluid,open the bleeder valve and then pump the brake lever after filling the reservour (be sure to put the top back on before pumping the lever.) This usually works well!

[nisus1]

yeah, that's what i thought too.  I just finished doing that and when i pump the lever, next to nothing is coming out.  I have a bleeder kit that i was using, but maybe i should get the one that actually has a pump on it.

Dunno...

[The Buddha]

You need to open the bleed screw at the caliper. Then connect the hose and suck out. Then after you add it back suck in a bit and as fluid is comming out and the reservoir has fluid... shut the bleed screw.
Cool.
Srinath.

[Trwhouse]

Hi there,
I had the same problem last weekend when I replaced my stock rubber brake lines with Russell Performance braided stainless steel lines. I couldn't get the air out of the lines even after 2 hours!
The next day I went to Sears and bought a Craftsman Vacuum brake bleeder pump ($49.99 for a metal pump) and brought it home -- hooked it up to the bleeder, opened the bleeder, then pumped the pump. BINGO! It sucks the fluid through the line using vacuum (stop OFTEN and refill the fluid reservoir!) and I was done in literally 5 minutes. I finished the process with a standard pump and open bleeder method to be sure all the fluid was air free.
Mity Vac also has a pump kit (plastic) at Sears for $34.99 and I saw the Mity-Vac kit under a different vendor's name on the package for $27 at AutoZone.
Any of the above will be great.
I'd never replace brake lines again without this tool!
Good luck and let us know how it goes.

Todd
P.S. I also used Valvoline SynPower DOT 3-4 synthetic fluid. It has a much higher boiling point and is good stuff.

[ash999]

Never had any problems bleeding brakes. You can make your own kit very easy. Get a bit of clear tubing to go over the end of the bleed nipple, 8mm spanner, little drinks bottle with hole in the lid and fill it to cover the bottom of the clear tubing which should be fed into the bottle. Then just open the bleed nipple and squeeze the lever in, then close the bleed nipple (Do that over and over)

The older your bike is (or the parts in the brake) the harder it is to bleed. I've experianceed problems before and if your brakes feel spongy but you cannot bleed them there is usually airtrapped in the master cylinder. My mate told me the best solution for that  is to leave the bike over night with the brake lever fully on with some tape around it to hold it on, and guess what, bled the brakes the next day and brakes are hard as a rock!!!!