cruiser54 Posted June 17, 2017 Share Posted June 17, 2017 Well, whatever you wanna call it, the passage that the fluid must go through to the front brakes is very small. It wasn't until I $#!&canned that POS that my front braking improved so much that I had to increase the pressure to the rears so it wouldn't nosedive. Having done this both ways, I would never use that distribution valve again. Just sayin'.. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 17, 2017 Author Share Posted June 17, 2017 Cruiser, can you post up a pic of your brake line setup? I'm still unclear of exactly what you did. Link to comment Share on other sites More sharing options...
Eagle Posted June 17, 2017 Share Posted June 17, 2017 Eliminate the factory prop valve. Using a T, join the pressure line from the master to the 2 front brake tubes. From the master cylinders pressure tube to the rear brakes, install an adjustable prop valve. At the rear, remove the height sensing valve and use a union to connect the lines together. Condemn the line that runs up to the engine bay to the old prop valve. Okay -- and now you have no brake system warning light. While I am well aware that anyone with half a brain should know if they've lost the front or rear brakes, I don't think it's legal to remove that feature from a vehicle that's registered and driven on public roads. And it doesn't gain you anything -- the MJ block that you eliminated doesn't have any proportioning function, so it's basically doing the same thing as the tee you installed. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 17, 2017 Share Posted June 17, 2017 Eliminate the factory prop valve. Using a T, join the pressure line from the master to the 2 front brake tubes. From the master cylinders pressure tube to the rear brakes, install an adjustable prop valve. At the rear, remove the height sensing valve and use a union to connect the lines together. Condemn the line that runs up to the engine bay to the old prop valve. Okay -- and now you have no brake system warning light. While I am well aware that anyone with half a brain should know if they've lost the front or rear brakes, I don't think it's legal to remove that feature from a vehicle that's registered and driven on public roads. And it doesn't gain you anything -- the MJ block that you eliminated doesn't have any proportioning function, so it's basically doing the same thing as the tee you installed. Correct on the first point and I'm the first to agree we shouldn't trust Don to drive a truck without that feature. Wrong on the second point. Where the fluid passes through the distribution block for the front brakes, and it goes right straight through, the orifice in the block is noticeably smaller than the inside diameter of the standard metal brake line running into and out of it. I ran mine that way for a while with the upgraded booster and master. I was disappointed in the braking power compared to my 88XJ which just required changing it's prop valve guts with the guts from a ZJ prop valve. So, I eliminated the distribution valve and put the tee in. That's when I noticed the difference in ID between the lines and the orifice. Brake lind ID is .100" and prop valve is .050"........ Keep in mind, this is not the first vehicle I've added rear discs to. Two Datsun Zs , two FJ40s, and a few others. You just let full pressure go to the front discs and regulate the pressure to the rear discs with the adjustable prop valve. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 17, 2017 Author Share Posted June 17, 2017 Hey dickwad, that wasn't necessary.......... Biotch. :yes: Link to comment Share on other sites More sharing options...
cruiser54 Posted June 17, 2017 Share Posted June 17, 2017 Hey dickwad, that wasn't necessary.......... Biotch. :yes: Still want photos? Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 17, 2017 Author Share Posted June 17, 2017 Got 'em. Couldn't you fix that with a drill? Or is the circuit channel internal groove at fault? Link to comment Share on other sites More sharing options...
cruiser54 Posted June 17, 2017 Share Posted June 17, 2017 Got 'em. Couldn't you fix that with a drill? Or is the circuit channel groove at fault? I'd have to see it again. Not sure which is the problem for sure. I just know what fixed it I guess. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 17, 2017 Author Share Posted June 17, 2017 Got 'em. Couldn't you fix that with a drill? Or is the circuit channel groove at fault? I'd have to see it again. Not sure which is the problem for sure. I just know what fixed it I guess. When I do mine, I'll drill out the block port holes for the L & R front wheel cylinder lines. It looks like the channel is big enough on Eagles cutaway block. Link to comment Share on other sites More sharing options...
Eagle Posted June 17, 2017 Share Posted June 17, 2017 I don't think there's any difference in orifice/passage size between the XJ and MJ valves/blocks/whatchacallems. XJ: MJ: Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 17, 2017 Share Posted June 17, 2017 My block looks nothing like your block.........apparently. Don't know what to tell ya. Edit: sorry, mine does look like the MJ block posted above, Link to comment Share on other sites More sharing options...
Gene Posted June 17, 2017 Share Posted June 17, 2017 I think this thread is in the running for most posts in the least period of time! :rotf: :rotf: Gene Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 17, 2017 Author Share Posted June 17, 2017 You can see how they are metered down just before they exit. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 17, 2017 Share Posted June 17, 2017 You can see how they are metered down just before they exit. So, you want to keep the block and eliminate the height sensing valve, right? Plug the hole where the block gets it's signal from the height sensing valve? Tie the rear brake pressure line together at the rear? Link to comment Share on other sites More sharing options...
kryptronic Posted June 18, 2017 Share Posted June 18, 2017 I've just bypassed the rear proportioning valve by replacing it with a coupler, using a YJ proportioning valve, and removing the hard line that ran to the front of the MJ distribution block. I have a D35 with rear drums. Brakes are exellent now with no lock up issues. A rear ZJ disc conversion is planned, and I'm sticking with the YJ valve for it. Of the XJ, ZJ and YJ valves, the YJ valve performs as desired on YJs with rear disc conversions, and it's engineered for a vehicle with a weight profile very similar to an MJ. Before I did the bypass, I considered just blocking the MJ distribution block and getting 100% pressure to the rear. I just wasn't comfortable with it. Link to comment Share on other sites More sharing options...
Eagle Posted June 18, 2017 Share Posted June 18, 2017 You can see how they are metered down just before they exit. Not really. I tried to cut them close to the centerline, but I wanted to be far enough off the center that I would screw fittings in and still have them stay there. One of them (I think the MJ unit) was done on a metal-cutting band saw in a friend's machine shop. The other one (probably the XJ unit) was done with a hack saw in a vise. If I can find my box of take-out units, I'll see if I can drop the same size drill bits into both (**IF** I have a spare MJ unit that's intact. I know I have several XJ units.) Link to comment Share on other sites More sharing options...
Top C Posted June 12, 2021 Share Posted June 12, 2021 So I have a 87 MJ with the factory brake system with rear height sensing valve. I have install a 3" lift in front and to balance the rear I installed Air shocks. I'm going to keep the rear drum brakes. I need to replace the rear brake lines, could I still eliminate this valve and connect the rear lines together and cut the sensing line and install a plug at the block without upsetting the braking system? Mike Link to comment Share on other sites More sharing options...
cruiser54 Posted June 12, 2021 Share Posted June 12, 2021 The best thing to do is eliminate the distro block. Connect the front lines together. Run a line to the rear with an adjustable brake valve. The distro block has small orifices in it which limit front braking. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 12, 2021 Share Posted June 12, 2021 Link to comment Share on other sites More sharing options...
Pete M Posted June 13, 2021 Share Posted June 13, 2021 The old rear lines are prone to rot by the gas tank. If you live in the rust belt, I would run a new rear line made from that copper alloy. Link to comment Share on other sites More sharing options...
Top C Posted June 13, 2021 Share Posted June 13, 2021 Thanks to both of you. Pete M you mention who carries the brake made of copper alloy? I was going to replace the line and that is a good tip. Mike Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted June 13, 2021 Share Posted June 13, 2021 39 minutes ago, TOP said: who carries the brake made of copper alloy Its called NiCopp. My local oriellys had a 25' roll in stock, but Amazon has better prices. Depends how fast you need it. Get gravel guard as well. If a job is worth doing.... I recommend getting a quality flare tool as well. It will save you hours of frustration. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 13, 2021 Share Posted June 13, 2021 Get this kit from summit: https://www.summitracing.com/parts/urr-br-ez316?seid=srese1&gclid=CjwKCAjw2ZaGBhBoEiwA8pfP_jl7-A7cMNJ7i74XoN6F3EDdn1ejZx-FK8gZGZeTg9kvIMZeFVOIjxoCJFEQAvD_BwE You’ll have everything you need to revamp your brakes and it’s a super quality kit with us made copper nickel line that has thicker walls than the Amazon stuff. Also, you can go with the Wilwood valve above or you can do the larger Wilwood valve which has the plumbing for bothe front and rear built in. Also has a nifty little bracket you can get for a clean install Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 13, 2021 Share Posted June 13, 2021 This was a wiring project but you can see the larger Wilwood valve mounted with the drop bracket onto an 01 XJ booster and master. Best non-hydroboost brakes I’ve had so far Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted June 13, 2021 Share Posted June 13, 2021 With respect Ghetdjc320, double check that price tag. THIS kit is almost as complete and 1/5 as expensive. OP, I am not sure how deep your pockets are, but shop around a little. I will agree that the Wilwood valve pictured above is great. Don't waste money on the bracket, its super easy to build your own and get better fitment around the booster. Link to comment Share on other sites More sharing options...
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