1969 Front Disc Brake (caliper) problems

[no69x-44]

I have been fight front disc brake issues for the last 2 weeks. It seems that whenever I step on the brakes the fronts go into line lock and I'm done. If I release the presure by backing off the bleeder valves, they seem to let loose, but then as soon as I hit the brake again ... Line Locked! The Master Cylinder, the power booster, all the lines & hoses have are all rebuilt or brand new. The back brakes work perfectly. I just replaced the propurtioning valve as sort of a last resort hoping that would fix the problem (another $100 down the drain)... to no avail. So all that I have left are the calipers themselfs. They are the orginals and have not been rebuilt. I just seems odd that both of them would be bad and behaving excatly the same. But it's the last piece that I have to replace.

Any thoughts on this? Any suggestions?

Thanks in advance.

[L78 steve]

Try cracking the lines in stages back to the master to isolate the point of pressure residual .Its probably the master.

[rich69rs]

Do you have the correct master cylinder for front disc?  Durm brake master cylinder have residual pressure valves (check valves) to hold pressure in the lines so that minimal pedal travel is required to cause the drum brakes to engage the drums.  MC for front disc will only have an rpv for the rear drum brakes, no rpv for the front disc.

Also, see the following:  http://www.camaros.org/forum/index.php?topic=2938.0