mid install: how do I bypass the height sensing valve?

[LocoJeeper]

Hey gang,

 

I am literally in the middle of my SOA on the rear, and want to address the rear height sensing valve in the brake system. I figured I would just bypass it, but theirs two lines going to the valve and splitter combo ... figure there would only be one from the front of the vehicle rather then two.

 

How do I bypass this thing? I would like to remove it completely now while I can still crawl under their without an axle in the way.

 

Thanks.

 

- Ben

[Eagle]

Best way is to run a totally new hard line from the front metering block directly to the rear axle brake hose. The old lines are probably rusted and weak anyway, so get rid of them.

 

The new line should come off the outlet in the "nose" of the metering block. The other outlet, the one on the underside and toward the front of the valve, is the outlet for the height-sensing valve bypass. If you run straight from the "nose" outlet to the rear brakes, the other outlet in the metering block should be plugged. You can do that by taking a standard fine-thread bolt (I don't remember what size, I think it's either 5/16" or 3/8" ), cutting it to about 1/4" in length, and putting an o-ring on the shank before screwing it into the hole.

[Pete M]

If you're doing any brake line work, I suggest replacing all the rubber lines too. And if your truck is lifted a little bit or if you ever plan on a lift, I would use YJ front lines and a rear line from a ~95ish Dakota. They are all a bit longer than stock. :thumbsup:

 

Pictures of the routing and what-not are in here:

 

http://comancheclub.com/forums/viewtopic.php?t=4968

[LocoJeeper]

Thanks guys. That should give me enough info to tackle the semi-project.

 

Already got all the soft lines (gmc something another up front and dakota rear) and I have some new hard line here (coiled in a box) somewhere. Would just need to run out and get replacement fittings.

 

Thanks again.

 

- Ben

[87mjdriver]

ya I was just under my rig looking at all that stuff. It looked like you could take apart that "T" that is forward of the heigth valve and just use a coupling to go straight into the rear line.

[LocoJeeper]

ya I was just under my rig looking at all that stuff. It looked like you could take apart that "T" that is forward of the heigth valve and just use a coupling to go straight into the rear line.

 

I thought that too, it was mentioned as a question in a previous thread... but I don't think anyone ever responded.

 

I am curious to find out, i am sure some one out in internet-land has tried it.

 

Anybody?

 

- Ben

[mjeff87]

yup, that's what I did.....

 

Jeff

 

Image Not Found

[Wildman]

ya I was just under my rig looking at all that stuff. It looked like you could take apart that "T" that is forward of the heigth valve and just use a coupling to go straight into the rear line.

 

I thought that too, it was mentioned as a question in a previous thread... but I don't think anyone ever responded.

 

I am curious to find out, i am sure some one out in internet-land has tried it.

 

Anybody?

 

- Ben

 

That about what I did, but I used the Tee up front, tied in the front nose line and the bottom front line together, then One brake line to the rear brake hose.

[Eagle]

If you disassemble the tee and run from that to the rear hose, you end up with not one but TWO connected lines running the full length of the chassis. Either one could rust through, so you're doubling the probability of losing your rear brakes.

 

The original poster lives in the rust belt. MJ brake hard lines very often rust out and fail just in the vicinity of the fuel tank. Since he wants to eliminate the height sensing proportioning valve anyway, it makes much better sense to replace both rusty old hard lines with one new line and not drive around wondering when your right foot is going to go to the floor at a stop light.

[jaekl]

If you do replace the T and couple the line from the front to the hose to the axle, you must also change the connections under the hood or you will have no rear brakes. Putting in a XJ prop valve would reduce the likelyhood of rear lockup. If you keep the MJ prop valve move the line you are using needs to be moved to the other port and the other one plugged. Many posts have this discussion.

[87mjdriver]

I read the other thread.

keep mj prop, cap the front bottom line (which is the failure back up)

figure out which line going into the "T" is the main supply.

then connect that line to the hard line that connects to the rubber hose

thus bypassing the heigth valve

 

I run 35's so the chance of lock up do to a high pressure would only slow me down not lock up.