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Alright folks, where do I buy a new/refurbished/used stock proportioning valve (or distribution block according to some, but I'm unsure)? I've been trying to bleed my brakes for 2 days now but my front right will not bleed, albeit by gravity, vacuum, reverse bleeding, the works. I've read in a number of places that the little "pin" in the proportioning valve has done it's thing where, when bleeding, it decides to cut off flow. Trouble is, I can't get the "pin" to go back to resting position. I tried manually pushing the pin after removing the brake light sensor gizmo on the prop valve, but that didn't work. Tried bleeding in different orders, that didn't work. Tried slamming the brakes with the engine running and not running. ETC. I tried everything but couldn't get that line to open up. Where can i find a replacement? If not replacement, what easy mod can I do to keep as much stock as possible? Base model 88 short bed - 4.0L 4wd automatic 75k miles -General notes: years of squishy brakes premature locking of rear tires when stopping general pull to one direction when braking ^^^ new repairs include all plastic lines, calipers, pads and master cylinder are new no mods 29inch tires no lift no pinches or clogs in rubber or solid line, from caliper to prop valve desire to keep as much stock as possible but willing to lightly mod to have a running jeep that stops for once Questions, recommendations, links to other posts, all are welcome.

Ok guys, what is the best route in dealing with that height proportioning valve on my rear brakes. It nasty it’s rusty and i don’t know that it even works anymore like it should. I have a suspicion that it might be clogged. Does that ever happen? I say that because when I bleed the rear brakes the brake fluid doesn’t gush out but rather spurts out. However when messing with the arm on the valve I got the fluid to bleed out better but still not like it should. Either way I’m doing some brake work back there and it’s time to address this valve. Can it be rebuilt? I know buying a new or used one is never going to happen. So if it can’t be Rebuilt what are my options. Is there a practical way to bypass it? Any input is appreciated.

Hey guys, If it's needed: 1989 with old Renix 4.0 - stock dana 35 I am trying to do a WJ master cylinder / brake booster swap since the old one was rusted out with a leaky booster. In the process of installing it I accidentally crushed the proportioning valve when putting the lines in so I have to replace it. I have put two new proportioning valves in but it leaks from the same two each time I thought I tightened it down without pushing the line in first so I put another in and clearly that wasn't the issue. I bought an XJ proportioning valve and will not be using the front brake line (deleting the special proportioning valve toward rear). I don’t want to throw another in there and just “tighten it down” because it’s about $80.00 (part + shipping + tax) with about a week and a half to get to my house and it would do the same thing. Regarding the lines: I took the fittings off the old MJ brake lines and put them on the WJ brake lines that I pulled from the junk yard with the master cylinder and booster. I couldn't get a good flare using a tool from an auto store so I took it to a brake shop and had them flare it for me. The fitting on top toward the rear is 1/2" and the other one is 7/16", all other brake lines (bottom and on the side toward the rear) are the stock brake lines and flares. Anyway, the ones that are leaking: Top toward the rear Bottom toward the front (see picture – also has part number for new proportioning valve) They leave indents like the line isn’t sitting centered. I push the line in first and make sure it’s sitting where it should be THEN tighten the fitting but it still does it. I can’t figure it out, the flares look okay (also pictured). But again, I’m new to this so I’m kinda stuck on where to go from here. Any help would be appreciated! If it’s the flares then can someone recommend a tool that is different than the standard $15.00 one from the Auto store? That thing is too inaccurate for how accurate these flares need to be and I can’t keep bringing these lines to a brake shop because the flaring they do isn’t working either (plus I would rather not remove that bottom line to flare it and cause another issue with the fitting further on down the line. Maybe a hydraulic tool that isn’t the $300.00 one from amazon?

So I've done a good bit of research and can't seem to find what swapping in a ZJ proportioning valve will look like. My plan is to swap to a '96 booster and MC from a ZJ, swap in a ford 8.8 (rear disc), and use the proportioning valve from the ZJ to delete the factory load sensing valve. Any info on the p-valve fitting sizes and line work that would need to be done would be great! Thanks in advance!

Hello All, So I'm new here but have been lurking and finding good info here since I picked up my first Comanche in Aug 2017, finally got round to creating a profile... I have some questions about the Comanche braking system, I've been reading posts on this forum on this topic as I'm getting ready to lift and axle swap to make sure I'm covering my bases and this one got my attention: https://comancheclub.com/topic/40762-mj-brake-proportioning-valve/ There is a good picture of the MJ distribution block cut in half in the linked thread: My question is why is there no metering valve associated with the front brake circuit? Am I missing something? Is it separate from the distribution block on each front brake line? For a Disk/Drum braking systems I was under the impression that it was important to have a metering valve on the front brake circuit so that the line pressure to the front is delayed such that the rear drums have a chance to apply first since the drum shoes are not in contact with the drum, whereas, the front caliper pads are in contact with the front disk and apply almost instantly when the brake pedal is actuated. A couple YouTubes on this: https://www.youtube.com/watch?v=qzUk8W1-2pw https://www.youtube.com/watch?v=tUEsxZGuMk4 My second question is related to a statement that 1stDeuce made regarding Wilwood adjustable pressure regulators: "The Wilwood adjustable pressure regulator that has only one inlet and outlet is often referred to as a prop valve, but it is NOT. It only functions to limit pressure to an adjustable set point, meaning it'll allow full pressure up to a certain point, then limit it to that pressure no matter how high input pressure goes." I have not been able to find information to support this just doing random Google searches today - Anyone have some insight on what the pressure curve actually looks like for a single inlet/single outlet style aftermarket proportioning valve such as the Wilwood? I was considering using one of these aftermarket proportioning valves along with the LSV delete procedure outlined in the link below to clean up the braking system a bit and have the valving in place for a rear disk swap later on (which would then likely negate the need {or maybe just my perceived need} for a metering valve on the front brake system): https://comancheclub.com/topic/53274-mj-load-sensing-valve-delete-procedure/ However, if the Wilwood single in/out "proportioning valve" is really a pressure regulator that allows full pressure up to a setpoint then flatlines the pressure regardless of the input pressure after that, seems like you'd be leaving some stopping power under-utilized as opposed to a proportioning valve that just affects the slope of the pressure rise curve after the "knee point" or adjustable setpoint. In the interim, my thought is to maybe try using a combination valve off an 80's K-series pickup as I believe I can find one that will have the rear proportioning valve, front metering valve and brake light switch all in one unit and swap that into the Comanche while it is in the disk/drum version and then keep the Comanche distribution block to be used later with the disk/disk, adjustable proportioning valve scenario when I get that project lined up. Thoughts? Also, 1stDeuce suggested a Jegs part as an alternative to a Wilwood proportioning valve: http://www.jegs.com/i/JEGS+Performance+Products/555/63025/10002/-1 However, I didn't see any description of a metering valve being part of that assembly so maybe a good option for a disk/disk setup but maybe not a disk/drum setup due to the lack of the metering valve??? That's all for my first post. Any help would be appreciated.

I could use some help. I did the WJ brake booster upgrade, but I had a leak at the back of the distribution block. Fluid was coming up out of the top of the rear fitting. Pulled everything out again, took a new set of lines to my mechanic--thinking maybe my lack of experience in making double flares was the problem--and put everything back in. Today I went out to bleed the brakes and finish the job when I noticed that fluid was already coming out of the rear fitting again, without ever having depressed the brake pedal. The line is new again and the brake line fitting is new again. Could it be my distribution block (or is it called a front proportioning valve)? If something is gummed up, can I fix it so the double flare seats right again? Or do I need to find a replacement block? Maybe there some other answer? Appreciate everyone on this site. It's been a huge help.

I recently finished doing an 8.8 SOA swap in my 1991 Jeep comanche Pioneer 4.0 manual. I need to do something about the brakes because they are seriously lacking in stopping power. Currently all I have done is eliminated the rear proportioning valve. I am going to swap in a 95/96 XJ brake booster, master cylinder and proportioning valve. My question is seeing that the 8.8 has disc brakes do I need to find a brake booster, master cylinder and prop valve from a donor vehicle that also has disk brakes or will a donor with drums work? What would be the best set up to keep the rears from locking up before the fronts under extreme braking conditions? Thanks in advance.

Hi Guys, I'm sure that there's already a post for this, but I couldn't find it.. But Anyways, I've seen pictures, and home made diagrams on how to delete it, but no detailed write ups, or pics.. :???: Any help would be greatly appreciated Thanks!