proportioning valves

[konastinky1234]

can you guys educate me on proportioning valves a bit? i am in the heat of my axle swap and this is the second to last part that i need but i don't really know which one i should get. i found some from summit racing for around 40 dollars which is cheap and they are adjustable. it would really help if anyone that has one of these could offer some advice hopefully. thanks guys

[Ktmracer419]

rear disc brakes?

get a zj proportioning valve (with discs)

you can swap the whole thing or just swap out the guts

[iant333]

I installed a ZJ prop valve to go with my rear discs, you can spend all the money on some crazy adjustable one, but even with swapped brakes the ZJ one should work fine as long as you have discs front and rear.

[iant333]

rear disc brakes?

get a zj proportioning valve (with discs)

you can swap the whole thing or just swap out the guts

I think you actually need to swap the whole thing, I just moved the valve thingy with the o-ring on it (no idea what ts actually called) over to mine and it spat brake fluid all over my engine compartment. I dont think they are compatible.

[Ktmracer419]

ive swapped the guts before with success

[HeavyMetal]

I think you actually need to swap the whole thing, I just moved the valve thingy with the o-ring on it (no idea what ts actually called) over to mine and it spat brake fluid all over my engine compartment. I dont think they are compatible.

FWIW i did exactly what you described and it worked fine on my XJ when i did the prop valve stuff

[Mike]

I pulled the oring off my stock valve and got good stopping power.

[iant333]

ive swapped the guts before with success

FWIW i did exactly what you described and it worked fine on my XJ when i did the prop valve stuff

Guess something was screwed up then.

[customcreationsllc]

yes you need to remove the o-ring from the check valve on the drum brake proportioning valve.

Drum brakes use about 12psi residual pressure check valve to counter the drum brake springs.
Disc brakes don't need residual pressure unless the master is lower than the calipers then they sell 2 psi check valves.

By removing the check valve o-ring it cannot hold the pressure back turning into a disc brake proportioning valve. The Pirate brake bible, has some good information.

The proportioning valve is also a called a combination valve because it also has a spool valve the shifts over if you blow a line to prevent you brake fluid from draining out. This also triggers the switch.


Your best cheapest way out remove the O-ring really only takes a minute then if you need to change the front/rear bias by the $40 summit adjustable brake proportioning valve. I've done this a few times very simple.



I've taken a few proportioning valves apart I cannot figure out how it actually proportions the front to rear. Any help here?