[AndyM]

Is the Brake Pressure Differential Valve the same for manual brakes and power brakes? I am thinking about buying a rebuild kit and on the WCCC website, it only mentions power brakes.

 

[1969XR7Vert]

Same, would only be different for drum/drum vs. disc/drum.

 

[AndyM]

Ok thanks, so I am not going crazy. I've got drum/drum. I just need to order a kit for drum/drum. I also read on a different post that the differential valve does not affect braking. Am I understanding that correctly? I will eventually get around to converting to discs but not for a while. I need to get it on the road first.

 

[1969XR7Vert]

Ok thanks, so I am not going crazy. I've got drum/drum. I just need to order a kit for drum/drum. I also read on a different post that the differential valve does not affect braking. Am I understanding that correctly? I will eventually get around to converting to discs but not for a while. I need to get it on the road first.

Only the disc/drum setup does as it has a proportioning valve for the rear brakes.

 

[AndyM]

thats odd, i will try to post a picture later. Maybe im not looking at the right thing.

 

[1969XR7Vert]

thats odd, i will try to post a picture later. Maybe im not looking at the right thing.

The block underneath the master cylinder that the lines go to. On '69 w/PDB (and likely before but not 100% sure) there is an additional cylindrical housing that is the proportioning valve, on '70 the prop valve is built into the distribution block.

 

[jcbingcougar]

You can find the correct parts to rebuild your braking system pressure differential valve here: www.musclecarresearch.com

They have kits for power disc brake cars and for drum brake cars.

 

[AndyM]

Ok. So I have read that when bleeding the brakes, I need to put something in place of the switch to keep the piston centered. Why? Why doesn't the switch keep it centered? I'm replacing the lines and rebuilding the valve since the car sat without any fluid for who knows how long before I got it so i want to do it right.