hey guys, i just replaced my front drums to disc on a 68.i cant get a good petal.i used parts from a 73 nova,spindles,backing plates,caliper brakets.i bought new roters,calipers,and brake hoses for a 69 at local parts store.my car has the prop.valve on the framerail under driver seat.it also has the block under booster with brown wire.i also bought a new booster and master cylinder.i should tell you it is power brakes,and was power before swap.what i'm confused on is do i need to get rid of prop.valve and block under booster? i checked out david's site.i think all i need is a comb. valve.the site says use one from 70 up.any help is appreciated,thanks in advance. :confused: dewayne

where is everyone?

For starters which new master cylinder did you buy? The one for a drum/drum application, or disc/drum?....

sorry rod,i got one for disc/drum

you bench bled the master cylinder, correct?
if not, pull it off and do that.

Went through something similar recently.............the master cylinder that I purchased from the local auto part store was a bad rebuild.

Same here. I did the WS6 T/A rear disc conversion on the 75 Camaro and I installed a rebuilt disc/disc master cylinder and booster. The brakes were terrible. Then I noticed fluid dripping on the garage floor under the M/C. Turns out that the M/C was pumping fluid from the rear resevoir to the front one. And eventually pushing fluid over the top (What a ugly mess I found). Apparently, one of the o-rings was missing so very little pressure was being applied to the rear brakes. Swapped out the M/C and shazamm!

Ok, i know this probably goes without saying...but im an idiot and screwed this up when i did mine. Do you have the bleeder screws on the top side. When i installed my disc brake conversion i flip flopped the calipers (right on left, left on right) therefore the bleeder screw was on the bottom of the calipers. You will never be able to bleed the brakes this way-- bleeder must be on top. I felt like an idiot when i called right stuff and we figured out that to be the problem. Then the guy on the phone told me i was the 3rd guy to call that week that had done the same thing. Guess im not the only idiot out there...or maybe he was just trying to make me feel better.

Is the brake pedal rod in the lower hole? I guess it should be already if they were power before.

thanks for the replies.the calipers were upsidedown at first but still not much of a petal after changing.the booster rod is in the lowerhole.this is the second master cylinder with no luck :clonk: thanks dewayne

A combination valve won't help a low pedal. Make sure your booster has the correct pusrod for your master cyl. I have info on the two depths of master cyls and two lengths of pushrods, don't mix them up or your pedal will be low.

thanks guys for all your help.what a great site! breaks work great now, i guess they still had air in them. thanks again.dewayne :beers: