To gut or not to gut... That is the question

So I swapped in the disks off a Grand Cherokeee this weekend. The brakes work great but I wonder if I should gut the proportioning valve? Some folks say yes and others say no. Please share me your knowledge and tell me what you have done.


Thanks

T

If by "GUT" you mean remove the restriction device from the stock disc/drum prop. valve, well, yes.

Here is a link to lunghd.com: http://www.lunghd.com/Tech_Articles/Suspension_Steering_Axles_and_Brakes/Proportioning_Valve_Mod.htm

Go Jeep also has a write-up on his website, but the server seems down right now: http://go.jeep-xj.info/

If you're going to gut the prop. valve, consider buying an adjustable in-line valve for the rear brake line.
Something like this.

When you gut the stock valve, there is no brake bias in the system other then what is there due to the difference in size of the various pistons. In 4wd(with the NP-231 anyway) this doesn't matter as much because any excessive brake force at the rear wheels is partially transmitted through the transfer case to the front wheels. In 2wd, a lack of front bias can cause the rear wheels to lock up under hard braking or slippery conditions. The adjustable valve allows you to tune the bias back into the system.

I was always under the impression that the proportioning valve does not proportion anything at all. The MC does that with the different sizes of pistons inside it. It is actually called a brake safety valve. This is incase your rear line goes and all fluid leaks out your still have front brakes or vice versa. I had huge rear discs on my old CJ from a dodge truck and I had the factory MC and prop valve and everything worked just fine. I could lock up the rear brakes if I slammed on the brakes hard enough but with normal driving on or off road my brakes worked fine. I did consider changing to a 4 wheel disc set up MC but it cost more and stock MCs for a 1986 CJ are cheap. I think if you get an adjustable one you will have nothing but trouble. You will have to flare new lines and run them into your interior and mount the switch in a suitable place. This is all well and good if you have a place that your knee won't hit or isn't out of reach. Also you will be adjusting it all the time because it will get bumped and played with by people who don;t know what it is for. I am doing a 4wd conversion from an Explorer on my 1993 XJ and I plan on using the stock MC. If I feel that something isn't right then I will get an MC from a ZJ and try that.

If the brakes are working well for you I wouldn't mess with it. If your rear brakes lock up going down a steep dirt hill and the front brakes don't then I would look at using a manual proportioning valve or do some research and see if taking the o-ring out of the stock prop valve is the way to go. Either way there should be some info on this site about it.

oops wrong button pushed....lol