Proportioning Calve / Combination Valve 74 Drums

After a ton of searching, I am still unable to find a correct answer to what I need. I read mid 74 used one but not sure what I need for an all drum setup. Starting all new brake lines soon and need to source parts. Some say just a tee to the front drums, others say combination valve, others say proportioning valve..

Input??

Thanks,

OLDSKOOL

 

No mystery here. The combination valve in a 1974 is well described in the TSM - look here at page 9-19. Jeep® 1974 TSM online

Are you missing the valve? If not, just reuse it and replace the lines only.

If its missing and you want to copy what was originally there, you need either an original combination valve or a collection of parts that will replace those functions. The valve has three purposes - provide a tee for the front brakes, provide a proportioning valve for the rear brakes that stops rear wheel lockup in hard braking, and a brake failure warning switch. Wilwood can probably supply something that will work. Wilwood Disc Brakes - Specialty OEM, Racing, and Street Performance Bolt-On Brake Kits Inline Tube sells a variety of distribution blocks Inline Tube - The brake plumbing experts

 

I would say if you're to buy a new valve, buy an ajustable one. If someday you turn front or rear to disk you won't need to buy a new one for the purpose.

 

If I were building the brake tubing from scratch, and I did not have the original valve, I would use one of the GM distribution blocks from Inline Tube (with the warning switch) like PR-106/7/8 and a separate adjustable proportioning valve in the tube to the rear. AFAIK there is no combination valve available that is exactly like the drum-drum type originally used. There are single-unit disk-drum types available, but they include a metering valve for the front that you don't want with all drum brakes.

 

Yep, starting from scratch. I will look into Inline Tube. As for the adjustable proportioning valve, Is that for if I switch to disks in the future or necessary to get the bias towards the front? Reading that before mid 74, there was no proportioning valve installed????


Thanks for the input. Great group of guys here....

 

If you are interested, Carolina Classic Trucks sells a new universal drum/drum proportioning valve.

 

Ok, this is that part - 5 port Drum/Drum Brake Proportioning Valve w/ Wire Sensor Plug

They claim it's for drum-drum brakes, and it has the warning switch and the right ports. The description is a little puzzling because they show a metering valve in their cutaway (which is what the disk-drum valves have), then the text describes a residual valve. The original valve has neither, with only a proportioning valve to the rear line.

 

It appears to be this part - https://www.amazon.com/Right-Stuff-PV72-Proportioning-Valve/dp/B009NRBBB8