Thanks for the quick replys. This is absolutely the worlds best site. Yes I have a Hydrovac, No I didn't bench bleed the master cylinder this time. I have not been working on the truck for a long time, and I forgot to do that, but I have done it in the past. 1herrick1. I actually think you may have the answer. I more or less came to the same conclusion, but I didn't know what to do about it. I'm not losing any fluid, except for a very small weep at one of the fittings. It doesn't take much to get the brakes going again, once I bleed them at the back wheel. This makes me think I must not have a problem with air in the lines, which leads me to believe the pressure on the lines must be drifting back to the master cylinder. If that is correct, what to I do about it. Will a new master cylinder kit fix the problem?? And why can't I now get the fluid to leave the master cylinder and pump out to the lines?? Thanks Allen
