Need help, CM400T Brake Problem

[colpumpkinnuts]

I've been lurking around on this forum for a while and have been meaning to post but haven't gotten around to it. Now I need help. I rebuilt the master cylinder and replaced the fluid resevoir on the front brake of my '79 CM400T. I bled the brakes for a long time. There were no more air bubbles coming out and the fluid was clear but there was no pressure on the pads and no resistance on the brake lever. I thought maybe the rebuild kit was bad so I put the old parts back in, bled them and now have the same results. Bubble free fluid flows out of the bleeder valve when the lever is squeezed but there is still no resistance on the lever. I have been bleeding the brake for hours with no change. Can anyone help?

 

[cbcafe]

A vacuum bleeder is the way to go when bleeding a fresh system that has been drained. I have had no luck trying to bleed brakes by pumping them. Cahurst had a thread elswhere in this section where i described the use of the bleeder. I am not sure if he ever tried it as he was still having trouble. He had a picture of a setup using a shop vac that might have worked if it could pull enough vacuum.

 

[colpumpkinnuts]

Thanks for the response. I just got finished bleeding the brake and it's working now. A mechanic friend of mine suggested pumping fluid in through the bleeder valve. So I hooked a syringe up to a piece of tubing and it worked great! This problem was driving me nuts! I think I might invest in a vacuum bleeder to avoid these kinds of problems in the future.

 

[cbcafe]

Cool idea. You pushed the air out of the master cylinder instead of pulling it. Sounds like an equally effective plan.

 

[colpumpkinnuts]

I definitely owe my friend a beer when he comes around again.