I just put the disc brake conversion kit from my 69 convertible, which is in 10,000 pieces and getting an SC&C kit when it goes back together, onto my 69 GS. I was having a problem bleeding the rears - no fluid of any kind was coming out. I had used the power drum booster with the disc master cylinder as I had done some searching that indicated that was ok. Well, just for grins I pulled the booster and compared it to the one from the vert. They were different - the vert one had a longer linkage to the brake pedal. So, I swapped them out. I also replaced both rear wheel cylinders.

I still wasn't getting any fluid to the rears, though. Frustrated, I pumped the brakes up really hard and stood on them as hard as I could. Well, the master cylinder kind of popped and then the pedal went down another couple of inches, and some fluid squirted out from the rear cylinder I was bleeding. So, I did it again. And again. Each time it got a little easier and I was finally able to bleed the rears.

However, now the problem is I still have a very soft pedal. I've bled all four wheels until well after no air was coming out (I used speed bleeders, which made it way easier). When I pump the pedal it gets hard, indicating there is air in the system, but yet none comes out anymore when I bleed. I;ve checked for leaks and didn't find any, and all connections are tight. The MC was bench bled on the car after installation.

This doesn't really sound to me like the MC is bad. Normally I would expect the pedal would slowly sink to the floor if the MC were bad, but it doesn't do that at all after I pump them up. It worked fine on the convertible and has been sitting in my basement since it came off last fall. Before that it sat on the car in the garage since July of 2006. Obviously the cylinder was stuck in the bore somehow and it took me standing on the brakes to get it loose, but now it seems to be working fine.

Any ideas?