Comanche proprotioning valve Q

I have a 90 Jeep Comanche

My rear brakes are bad, I need to replace all the lines from a little before the proportioning valve and all of it afterwards. Im talking about the valve near the rear axle for when you have a load in the truck, to give the rear more power when its loaded.

Will I have brake problems if I just skip the whole valve and just run the brakes right the the wheel cylinders. If I skip the valve it saves me a lot of line and money. Plus when I lift the truck the valve will be way out of wack anyway.

Basically I want to know if I will have any problems if I skip that valve. Just the clarify, im not talking about the valve up at the Master cylinder.

I have a 90 comanche as well. Since I got the truck the valve has never been attached to the axle. It has bounced around from full up to full down and it never really seems to have affected the braking of the jeep.

It should be noted that I don't tow or usally carry anything heavy in the bed.

I'm curious though -- what is the position of the lever relative to the axle (and does it point to the passenger side or the drivers side) with the linkage connected? I have been looking for this info for a while and have come up empty handed.

Thanks!

tetsulo

tetsulo said:

I have a 90 comanche as well. Since I got the truck the valve has never been attached to the axle. It has bounced around from full up to full down and it never really seems to have affected the braking of the jeep.

It should be noted that I don't tow or usally carry anything heavy in the bed.

I'm curious though -- what is the position of the lever relative to the axle (and does it point to the passenger side or the drivers side) with the linkage connected? I have been looking for this info for a while and have come up empty handed.

Thanks!

tetsulo

Click to expand...

Lever points to the Pass side, and lever DOWN unloaded.

When the body drops, the lever is pushed up.

People have had good results with using an adjustable Prop valve from Summit.

Storydude said:

Lever points to the Pass side, and lever DOWN unloaded.

Click to expand...

you mean parallel to the rear axle with no load? or should it point towards the axle at an angle?


tetsulo

Pointing to the axle. What * , I'm not sure.

With no load in the truck the arm should be basically parallel to the ground.

That's the only proportioning valve in a Comanche. As near as I can figure, the front "combination" valve on a Comanche doesn't appear to be a "combination" valve at all, just a brake system warning switch and a distribution block. There is a return line going into the front of the "combo" valve on the MJ that isn't present on the XJ. If you abandon the rear proportioning valve, you'll need to block that outlet.

The result will be that you will always have full braking to the rear wheels. The rear proportioning valve on my shortbed MJ blew up (literally) when I was bleeding the brakes after replacing a rusted out line, so I had to eliminate it to get the truck back on the road. 99% of the time it drives like it should, except that the rear brakes are more effective than the rears on my XJ. However -- there was one instance when approaching a stop sign going down a steep incline on a rainy day when things came rather unglued, because on the downslope ALO the weight was on the front wheels, and the rear locked up rather dramatically. It's that situation that the proportioning valve is supposed to prevent.