I have a 71 chevelle...I just swapped the drums out for a set of front factory disc. After Finishing the install, I bled the system and got out much air. I still have the manual non powered master cylinder in and stock Proportioning Valve. The First time after bleeding I hit the brakes it hits the wood (floor) and then you have to pump it up like 5 times to get a good pedal. I am wonderng if I need to convert to a power system..which i really do not want to do or just change the proporting valve...anyone been here before thx for the help..:beers:

you still have air in the system.

I have bleed the system....completely...still no pedal till you pump it up after 5 or 6 times.. as i read last night the caliper requires more pressure and volume to push out then a wheel cylinder...thinkin i might go get a master cylinder for a front disc and rear drum car

Bleeding the system was tricky for me, from what I understand also it is required to have the disc/drum master cylinder for the system to operate properly so that might be all you need.

When I went to disc on the front of my car,the proportioning valve had to be changed

kinda what im thinkin i called wilwood and talked to them...suprisingly enough he didnt try to sell me one of their high volume master cylinders...I still have that drum drum master cyl. on and just power bled the system again same result..ran one quart just through the fronts..have perfectly clear brake fluid now...lol....i can hear the rears working about half way to the floor but just nothing from the fronts till i pump it 5 or 6 times then i get a rock hard pedal thats solid no spongyness and as soon as i let it go gone pump again

When I went to disc on the front of my car,the proportioning valve had to be changed

did ou have to change the master cylinder?
:confused:

did ou have to change the master cylinder?
:confused:
Nope,We actually addeded the power booster to my drum brake master cylinder and I just went to my local chevy dealer to get the disc/drum proportioning valve.

Oh ha that's what I was lookin for I had been reading I could leave on my stock master and just put in the discs and when it didn't work..oh man..thx for that bit of info ill try the valve first...don't really want to make them power cause im going to be supercharging soon...

well guys tried the porp. valve to no effect...I then said to hell with it and went and bought a master cyl. for a front disc rear drum car...mind you the res that was on my car was the small/small res...not working...so the new one had a large rez. for the front a small for the rears...I installed it and had to change the lenght of my push rod no big deal...bled the system and low and behold with no booster I now have brakes....little to not noticing i also now have a brake fluid leak...(ill fix after work)...but thx for all the help guy I found my specific problem to be the master cylinder....Dawrench

You have to use the correct master for disc/drum.

well boyz the price of your chevelle just went up a little more...right after i got her all finished up and took her for a cruz to the parts store some stupid women side swipped me and totalled my chevelle..(she made a left turn right into the font of my baby)...mind you my new disc/ drum setup worked kick ass but I could not get away from her.stuffed my rear quarter through her car...her fault...not mine we drive our cars like we built them...to just cruise...to get them looks, like damn thats sweet...Well now they go DAMN!!!!!! what happened....not sure if ill ever be back on here again so thx guys for all the help...may God be with all your toyz....Dawrench