Long story short. I did a drum to disc swap. All new parts. Bled everything correctly. I have a spongey pedal, and my master cylinder will not stop seeping down the booster. I've replaced the master cylinder/booster 3 times its gettn old. I also rebuilt the rear drum brakes. Any, ideas or suggestions will be appreciated greatly. Should i have changed something on the pedal? O yeah it is a 70 chevelle.:confused:

"seeping" as in leaking?

Yes. sorry!

Did you "bench bleed" the master? The fluid has to feed back into the chambers as you pump it. It's a cheap plastic kit that connects where the lines fit and you just run the ends of the hoses into the chamber. These MUST be covered in fluid when priming.

I'm betting you're pumping air around inside the system causing the seeping.

Also check your brake pedal push rod length. Some are long and some are short, any mismatch won't work. I have heard something about two different holes on your brake pedal arm too..........one is for drum and one for disc's. I believe you switch down to the lower hole w/ P/DB because your master cylinder is at more of an angle with the big power booster. Maybe that's your problem...........you kept it in the upper position and over stroked your master cylinder causing the seals to fail.

Also check your brake pedal push rod length. Some are long and some are short, any mismatch won't work. I have heard something about two different holes on your brake pedal arm too..........one is for drum and one for disc's. I believe you switch down to the lower hole w/ P/DB because your master cylinder is at more of an angle with the big power booster. Maybe that's your problem...........you kept it in the upper position and over stroked your master cylinder causing the seals to fail.

Kinda Sorta. The upper hole in the brake pedal arm is used when the vehicle is equipped with manual brakes regardless of front brake type.

The lower hole would then be used when equipped with power assist.

How long should the rod be? I've heard of this before but did'nt find the length. It is in the lower hole on the pedal already though.

Did you "bench bleed" the master? The fluid has to feed back into the chambers as you pump it. It's a cheap plastic kit that connects where the lines fit and you just run the ends of the hoses into the chamber. These MUST be covered in fluid when priming.

I'm betting you're pumping air around inside the system causing the seeping.
No i did'nt! Thanks I'll try that and see what happens. Not real sure how to do it though.:thumbsup: