Brake conversion.

[justadayplayer]

Hey people. I have a '71 B body i am converting from 4 wheel manual drum to manual front disc/ rear drum.

My question is: do i need to replace proportioning valve? I have a disc/drum master cylinder for swap.

Thanks in advance!

 

[MWbirdLOVER70]

Hey people. I have a '71 B body i am converting from 4 wheel manual drum to manual front disc/ rear drum.

My question is: do i need to replace proportioning valve? I have a disc/drum master cylinder for swap.

Thanks in advance!

On my 70 I used an adjustable valve to the rear brakes. Others should chime in with advice and maybe a pic of the valve

 

[R/T Boy 67]

Yes. Add an adjustable proportioning valve to the rear brakes after the pressure differential valve/ junction block that is in there now.

 

[AMX364]

I got my best adjustment by driving in a parking lot with glare ice. It was hard to do in Texas, but it can happen.

 

[justadayplayer]

Yes. Add an adjustable proportioning valve to the rear brakes after the pressure differential valve/ junction block that is in there now.

Thanks for reply. I did locate a "metering block" that is For disc/drum brakes. OE style. This will eliminate the need for an adjustable proportioning valve; correct?

 

[71Beeper]

Yes, replace the proportioning valve.
I have the same set-up that you are going to do.
I used the proper proportioning valve.

One of the ports is plugged as I'm also using a line-loc - you can see the bottom of it just under the proportioning valve.

 

[justadayplayer]

Yes, replace the proportioning valve.
I have the same set-up that you are going to do.
I used the proper proportioning valve.
View attachment 1569226

One of the ports is plugged as I'm also using a line-loc - you can see the bottom of it just under the proportioning valve.

 

[justadayplayer]

Yes, replace the proportioning valve.
I have the same set-up that you are going to do.
I used the proper proportioning valve.
View attachment 1569226

One of the ports is plugged as I'm also using a line-loc - you can see the bottom of it just under the proportioning valve.

Nice work! Thabk you, this is great help.

 

[R/T Boy 67]

You could use the factory valves, and they would probably work fine, if your system is stock. Any modifications from stock, including tires, or lightweight engine parts ect. could alter the braking balance. One other thing, while I'm here. The brass lump under your master cyl on your drum brake car, as well as the one in post 6 are not proportioning valves. They are pressure differential valves. There were three valves used on most disc brake systems of the Era. The pressure differential, the metering, and the proportioning valves. They combined all three into one combination valve by the early 70s.

 

[justadayplayer]

You could use the factory valves, and they would probably work fine, if your system is stock. Any modifications from stock, including tires, or lightweight engine parts ect. could alter the braking balance. One other thing, while I'm here. The brass lump under your master cyl on your drum brake car, as well as the one in post 6 are not proportioning valves. They are pressure differential valves. There were three valves used on most disc brake systems of the Era. The pressure differential, the metering, and the proportioning valves. They combined all three into one combination valve by the early 70s.

Thank you. I purchased a master cylinder with adjustable proportioning valve this afternoon

You could use the factory valves, and they would probably work fine, if your system is stock. Any modifications from stock, including tires, or lightweight engine parts ect. could alter the braking balance. One other thing, while I'm here. The brass lump under your master cyl on your drum brake car, as well as the one in post 6 are not proportioning valves. They are pressure differential valves. There were three valves used on most disc brake systems of the Era. The pressure differential, the metering, and the proportioning valves. They combined all three into one combination valve by the early 70s.

I purchased master cylinder w/adjustable proportioning valve this afternoon. I should have everything i need now.



Thanks for response