Height Sensing Valve Rebuild?

[flint54]

Yes, I know it can be bypassed but I'm not there yet. Found the large C-ring (that holds the thing together) missing on mine. Found a replacement valve at the JY today. Not sure how to test it. I can blow through the valve while rotating the arm and do not sense any restriction due to arm position, even though the arm has some resistance through a small portion of it's arc. I would like to attempt a rebuild, even though the FSM doesn't discuss. My reasoning is that the unit would not have been designed for disassembling if it wasn't intended to ever be serviced. Have any of you ever opened one of these units and restored the function? Sure would be nice to have some info on this. Thanks!! Tom

[Pete M]

I applaud your ambition. :thumbsup:

 

But being designed "with serviceability in mind" is different than building a thing that still technically happens to come apart. :(

[HOrnbrod]

The MJ height sensing valve was never designed to be rebuilt, just replaced. AMC/Mopar never offered a rebuild kit for it, like say a brake caliper. As far as rebuilding it it probably could be done if you could source the o-rings and seals inside.

 

Testing it by blowing through it won't work, as you will always be able to blow through it at any arm position for safety reasons. It would have to be tested under the same hydraulic pressures it has at no-load/full load as it was designed for in the real world, with pressure gauges on the inlet and outlet sides of the valve. And those original hydraulic pressure tolerances would be impossible to find now. When I did my lift and installed rear disk brakes I got the valve to correctly bias the rear disk brakes working as it should by installing an adjustable actuating rod and doing skid tests in a wet parking lot.

 

http://www.comancheclub.com/forums/viewtopic.php?f=9&t=17968&hilit=adjustable

[flint54]

Here's to skid tests! :cheers: Was you goal to achieve lockup of all four together?

 

Well, if the experts say it hasn't been done (yes I knew there wasn't a kit), I guess I might be charting new territory.

When (if?) I get the thing open I'll post some images of what I find. I just cannot let go of the curiosity.

 

Tom

[HOrnbrod]

Here's to skid tests! :cheers: Was you goal to achieve lockup of all four together? Tom

 

No, I wanted the normal 60%-40% front-to-rear ratio during normal braking with or w/o load. But full lock on a panic stop. In checking front and rear pad wear, it seems to be working fine.

 

Yeah, open her up. I'm curious too. :cheers:

[91coMANche]

In theory and in application its a wonderful concept...mine is leak free and I hope it stays that way. The idea makes so much sense that I think a new 2011 Ram 6.7 Diesel could sell better with this "optional" like a jake brake.

[reece146]

Read this thread and the linked thread...

 

To be clear - you never want the rear brakes to lock before the front brakes. If the rears lock first the rear will spin the vehicle. It's hard to accomplish in practice, especially when heavy loading of the vehicle is involved. Hence the load sensing valve.