Previously my car was 4 wheel manual drums. I have converted it to power front disks.

Booster is a reman from the parts store, the master cylinder is a power front disk 72 Chevelle unit and is new. Front disks are brand new from CPP brakes. Proportioning valve is a Disk/Drum unit brand new from CPP. New front brake lines from Fine Lines.

When I mounted the booster, I moved the pedal clevis to the lower hole on the pedal.

I finally got around to bleeding the brakes today. The master cylinder was bench bled until there was no more air coming out of the ports and the fluid was flowing smoothly through the clear lines.

I mounted the master cylinder on the car... With my gf pumping the brakes I opened the wheel cyl on the passenger rear, I got a very light trickle of fluid. She pumped the brakes up again and the fluid got a little stronger. Third time, absolutely Zero fluid came out. Tried the driver side rear, not even a trickle of fluid came out. I asked her if the pedal got harder as she pumped it "No." I get in the car, pump the pedal a good 30-40 times, just goes straight to the floor.

I had some minor leaks, but have tightened and eliminated all of them. I then had the gf pump the brakes again while I opened the front drivers side, absolutely ZERO fluid came out.

I do not have the engine running as I wanted the brakes done first, however I have bled plenty of power brake cars with the engine off so that shouldnt affect it right?

I have spent the last 2 hours searching and reading the archive, I am at wits end. Call me stupid, point out the obvious, do whatever, I have Never had this problem before and am beside myself on what the heck it might be.

Any and all input is welcomed, thank you in advance!

crack the lines on teh master cylinder, place the lines back in and bench bleed again just to see if something has happened there. If you have fluid transfer, place the hard lines back on, and crack them at the proporitioning valve and check at that poing. Im not sure about any of the actual inner workings of the master cylinder, but in the warning it said not to push the piston of the master cylinder more than X" or damage would occur. Just some food for thought.

Make sure there is enough free play on the brake pedal pushrod so it's not applying pressure to the m/c.
I've had this happen before...the m/c piston can't fully return to recharge the chamber with fluid.

Make sure there is enough free play on the brake pedal pushrod so it's not applying pressure to the m/c.
I've had this happen before...the m/c piston can't fully return to recharge the chamber with fluid.


I think you may have won the prize Bill. I messed with the pedal assembly for about an hour after work today. I couldnt get the pushrod to back off any, so I put a couple of washers behind the master cylinder to space it away from the pushrod. After that wala! Fluid movement when bleeding.

Only problem is now that the pressure tapered off on the passenger side rear and on the drivers rear I can't get any fluid at all and there are no obvious leaks. :confused: I don't know, but at least there was progress.

Check the flexible rubber line that connects the hard line coming from the master cylinder to the rear axle :thumbsup:

Is that pushrod always too long? :confused: I had to do the shim trick on my car, and I have noticed a ton of posts about the same problem.

I always ask this because I've seen it done... you did mount the calipers with the bleeders on top, right?

I always ask this because I've seen it done... you did mount the calipers with the bleeders on top, right?

Yes, I did.

Check the flexible rubber line that connects the hard line coming from the master cylinder to the rear axle :thumbsup:

Thats a good idea. I think thats probably the only part that has never been changed unless it was changed by the shop that did the brakes on it 3 or 4 yrs ago while I was away at college and the car was here at home. I'll check it out, and replace it for nothing else but peace at mind.

I had a similar problem and worked my way back cracking the line open from the rear wheel cylinders back and that hose was the culprit on mine.
POZ