question about proportioning valve 72 malibu

[60ratrod]

Ok so i have most of the part for the disc brake conversion on my wife's 72 malibu. Only things left to get now are pads, bearing seals, cotter pins and a proportioning valve. The only part that i can't seem to find locally is the proportioning valve. So i was wondering how essential it is to have the disc brake proportioning valve? Will i run into any problems with the stock 4 corner drum valve if i don't get and install the disc brake prop valve?
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[foxhole]

yeah takes alot more fluid to move a caliper than a wheel cylinder, your drums will lock up in the back. try cpp

[stich626]

Originally Posted by foxhole

yeah takes alot more fluid to move a caliper than a wheel cylinder, your drums will lock up in the back. try cpp

that will not matter, the disc brake master has a bigger fluid hold for the front disc..
that valve doesn't really control much of the front brake bias.
it's mostly the rear, and that didn't change as your still drum in the back..
the bigger issue is was the residual valve in those cars in the master cyl port or that valve, as it keeps 10-15 psi on the drum system to keep the drum shoes from backing off. on a disc system it'll cause them to drag.

[foxhole]

yeah your right, it's late and i was thinking drum/drum vs disk/drum master not proportioning valve. CPP still may be able to help you out or ssbc makes an economical adjustable proportioning valve and the good thing about those is since you have to redo all the lines any ways it's a great excuse to install line Lock.

[60ratrod]

ok so i will need the disc brake prop valve. well after i posted this last nite i took a look on ebay and found a couple. i would rather use the oem style prop valve for ease of installation.

[oldblue1968chevy]

aftermarket fits just the same

cheapest i found was speedway motors they have disc disc and drum disc

[60ratrod]

the cheapest aftermarket one that i have found is a universal unit and i would have to change the lines around and that's not something that i wanna do right now. cause when i tried to pull the prop valve from the donor that i got the disc setup from i noticed that it had ports for the front and rear lines unless i was smoking crack when i was pulling the assemblies

[oldblue1968chevy]

I forgot this is a car...

On my truck, I got a disc drum prop. vavle, and a brass prop vavle disc drum with bracket/pre bent lines it matched up perfect, lines were a few frog hairs off but nothing a second of tinkering slightly bending didnt fix..