70 disc conversion experience [Archive] - Chevelle Tech

: 70 disc conversion experience


Kolt45
Jun 30th, 10, 6:03 PM
I first wanna say how much I love this site, it has helped me more times than I can count.

A couple years ago when I bought my 70 Chevelle I bought a used GM A body disc brake setup off Craigslist. I couldn't stand the drum brakes. The disc set up came with the master cylinder/booster, lines to the distribution block, distrobution block and the disc assembly with calipers, rotor etc.

Everything bolted on great and the only issue was that the car would pull slightly to the left while braking. I was upgrading my suspension and wheels/tires, so I though it might go away after I get an alignment done.

To give the car more of a factory look I bought a rebuilt rectangle master cylinder with the bleeder valves. I also replaced the rear brakes and adjusted them evenly with a slight amount of drag. I also triple checked the master cylinder/booster rod to insure it was the correct length.

After the alignment was all squared away, I noticed the car still pulled to the left. I purchased rebuilt calipers. Still pulled... I put new front tires on and noticed the right front was dragging. It was dragging more than the left front. But both were dragging quite a bit. I loosened the master cylinder and it didn't release the pressure, the brakes were still dragging.

With the calipers changed out and the Master cylinder, I decided to replace the distribution valve for a PV2 proportioning valve. I bought the prop valve and frame bracket. Hooking it up last night I ran into an issue with the left front brake line connector being too big, it wouldn't screw into the prop valve and the front supply line connector was too small. I tried to find the adapters locally, but then just ordered the 4-piece brake line kit for a 71 from The Right Stuff, I should get the kit next week.

I really hope the new lines and prop valve, along with proper bleeding of the system fixes the pulling and dragging issue.

Anyone have a similar experience? I now wish I would have bought a full conversion kit from inline tube or the right stuff.

Thank you,
Kolt

GenPac
Jun 30th, 10, 6:47 PM
Just to make sure, you bought new flex lines, right? lubed up the caliper slides well?

Kolt45
Jun 30th, 10, 7:36 PM
I also replaced the flex lines and bought new frame brackets. I'll be sure to lube the caliper slides.

Thanks for the advise!

Carchisler
Jun 30th, 10, 9:54 PM
You want to check one more thing. Where the rod from the pedal is connected to the booster. Make sure there is a bit of free play in that brake pedal.
Maybe the pedal is holding a bit of pressure on the front discs causing them to drag?

MCB
Jul 27th, 10, 5:25 PM
Carchisler is right its the number one issue we see.....pedal free play, you don't need alot, just enough so you are positive there is no bind!