Disc/Disc proportioner?

[5150.4.67]

Was curious what proportioner I need with my new rear disc setup (Speedway)? Any ideas?

[70cst]

I would help you out as I am mechanically challenged.

[tcb-1]

I ordered mine from CPP. I believe the pn# was PV1.

I know Speedway has one, but I don't have the pn# or catalog in front of me.......

[gcburdic]

order one from here....they are made right here in NC....
http://www.piratejack.net/Proportion...lves-Kits.html

I believe it's a PV4 on this web site.....

[Longhorn Man]

unless you got an entire kit, from master cylinder to front brakes to back brakes.... there will be no proportioning valve that is just right. If you only do part of the brake system, the right hand literally has no clue what the left hand is doing.
I highly recomend plumbing a 67 - 70 distribution block, and then an adjustable proportioning valve.

[pumpkin]

I used a drum brake p-valve, and cheep offshore roters on the rear and it worked out perfect. With the cheap rotters, you lose about 20% of your stopping ability over stock, or good quality roters, so for me it worked great.

[Longhorn Man]

I also recomend reading up, on stuff written by people who know whats what.
If you are mixing and matching, there's hyd line pressure readings you should take, to verify things like "a drum proportioning valve worked perfect".
pumpkin... if I was a betting man, I'd bet a kick to the daddy parts, that your drum brake proportioning valve is not just right.
it's just good enough.

[Orange]

Call Mike -
http://bumpandgrindgarage.com/

He's a supporting vendor and will give you a discount on an already great price.
He will also give you technical support.

DLB

[LONGHAIR]

I'm not taking the "parts kick" but I will bet that you have dragging pressure on the rear lines. This will create more heat and wear out your "cheap rotors" even faster. It is not good for anything else for that matter. Drum systems keep 10PSI in the lines with a "residual pressure" valve.

[GMCPaul]

Distribution block, this block was used on all 67-70 trucks, with front drum / rear drum brakes. The block is bolted below the master cylinder and is not a proportioning valve as it does not modulate line pressure. If there is a loss of pressure in either the front or rear braking systems, it will activate the brake warning light in the dash. Since this block provides equal pressure to the front and rear brakes it is also great for 4 wheel disc applications.
These distribution blocks do not have residual pressure valves in them.
Residual Valves:
These valves are used in brake systems where the master cylinder is mounted lower than the calipers, typically under the floor. This is a check valve that keeps either 2lb (disc) or 10lb (drum) of pressure in the system to prevent the fluid from running back and overflowing the master cylinder. These valves should be mounted as close as possible to the master before the proportioning valve. These valves are not needed on firewall mounted master cylinders.
Thus the reason our distribution blocks did not require a residual pressure valve.
A alternative to using a distribution block is a disc/ disc prop valve which again applies equal pressure to both.
I was taught this by Inline Tube.
GMCPaul

[chevy_mike]

Originally Posted by GMCPaul

Distribution block, this block was used on all 67-70 trucks, with front drum / rear drum brakes. The block is bolted below the master cylinder and is not a proportioning valve as it does not modulate line pressure. If there is a loss of pressure in either the front or rear braking systems, it will activate the brake warning light in the dash. Since this block provides equal pressure to the front and rear brakes it is also great for 4 wheel disc applications.
These distribution blocks do not have residual pressure valves in them.
Residual Valves:
These valves are used in brake systems where the master cylinder is mounted lower than the calipers, typically under the floor. This is a check valve that keeps either 2lb (disc) or 10lb (drum) of pressure in the system to prevent the fluid from running back and overflowing the master cylinder. These valves should be mounted as close as possible to the master before the proportioning valve. These valves are not needed on firewall mounted master cylinders.
Thus the reason our distribution blocks did not require a residual pressure valve.
A alternative to using a distribution block is a disc/ disc prop valve which again applies equal pressure to both.
I was taught this by Inline Tube.
GMCPaul

This is great info. I am getting ready to do a 4 wheel disc conversion on my '68 and now I know I will keep my drum/drum valve and not change to something else. I will plum in a adjustable valve after the distribution valve on the rear line, just so I can tweak the rears.