dotnetrob

Rear valve has already rusted thru and disconnected when I got the comanche unfortunately. Just installed a adjustable proportioning valve from Jegs, so far so good.

Yet another update. Guess I didn't test the XJ distribution value enough before posting success. The XJ distribution valve indeed does work better, but is not even close to perfect. It still locks up the rear even when braking lightly. Working on a new plan.

Finally have working brakes on my comanche. Took it to a different shop and had them diagnose the issue. Looks like the rear brakes that were fixed/repairs/replaced by the first shop were not done very well and also needed adjustment. So the XJ distribution valve worked. Super happy to finally have a drive-able comanche. Now to start work on the other 100 things on the to fix list.

They are 31x10.50F15LT firestone destination a/t, rear are at 32 RP and 33 RD. Front are at 29 FP and 32 FD.

Alright, finally updating the long, still on going saga that is my Comanche's brakes. The stock Comanche distribution value fittings were so rusty that even heat and penetrating oil couldn't help, ended up breaking multiple fittings and lines trying to get things apart. Tried making some new brake lines but apparently I am incapable to making a good double flare, even bought a different tool and ultimately decided my dream of becoming as a good brake line flairer was not meant to be. So I gave up... Ended up calling a local 4x4 shop I had used many many times on both my JK and TJ. Had them come get my MJ, since I had now messed up the brakes pretty good. They decided the best route was to replace the distribution value with one from an XJ and replaced about 1/2 of one of the lines going to the rear. So now just 1 line going to the rear from the XJ valve. Was going to have them do some other work since I like being lazy, but for some reason they pretty much just sat on my MJ and didn't make much progress past the XJ distribution valve, kind of frustrated they had it a month. They mentioned the rear brake where making noise when stopping but they said the brakes were much better. So I got excited and decided to go ahead and pick it up and for go any other work, heck the brakes should work now right.... Picked it up late yesterday evening and drove it home. The brake pedal is a little better, not a mushy pedal 80% of the way down, brakes feel... better, maybe, a little, but still feels weak to me. But drove it home 80+ miles in rush hour traffic, was a bit of a rough experience, but it made it home. Today took it out for a drive to get lunch with my son and it was a horrible experience. Brakes still feel weak, pedal is a bit mushy. But I have all new brakes up front(everything), rear brakes are rebuilt( by other local shop), and now have an XJ distribution valve. At the second stop light I came too, had to brake a bit hard, light turned as just the right time, wasn't even close to an emergency stop, but the rear brakes locked up hard, took the comanche a good bit side ways. Extremely frustrated with myself, the shop. Maybe the rear drum brakes need to be adjusted, unfortunately I know so little about drum brakes, except I worked on them as a teen with my first truck a few times and have hated them since. Don't really want to take it back to the shop, long drive, owner is apparently on vacation again and he is apparently the one I would need to talk to but he won't call me. I guess I am hard to work with or people just don't like me. Maybe both... Either way, I once again have an undriveable comanche that needs tons of work... but I can't even get the brakes working why work on the rest.

These Napa pads are the pads I ended up with. Hopefully they work well. If there are pads anyone recommends please add a link. Working on getting the brake lines and fittings I need to do the plumbing changes. Already own the line bending tools and flaring tools, just need the fittings and line.

Finally have an update. Broken and rusted shut bleeders, 1 rotor was in bad shape, rusted onto the wheel bearing and corners of the rotor was all beat up. Rusted on dust covers, or what was left of them. 1 of the pads on the passenger side was partially broken, 1/4 of the pad was missing. The driver side drive shaft nut would not come off, so removed the drive shaft with wheel bearing all in one piece. With all the carnage, everything needed to be replaced. Cleaned and painted knuckles Replaced the drive side drive shaft. new axles nuts and caps on both sides Installed 2 new wheel bearings. Installed 2 new dust shields. Installed 2 new rotors. Installed 2 new calipers Installed new brake pads on both sides. All installed and front brakes bleed. Was going to do a CAD delete while I was at it but need to stay on task for now and get the brakes working. After taking a quick test drive, there is an improvement. Not huge, but noticeable. Would say before I replaced all the front brakes, braking power was maybe 20%, would say its maybe 30% now. Still horribly weak, but does stop better. After looking at @coolwind57 write up. I believe I am going to add a proportioning value up front near the master cylinder for the rear brakes and convert the rear brakes to 1 line to the rear. Anyone see any issues with this idea? Attached a horribly drawn diagram of the current and proposed setup.

1J7FJ36L1KL612412 189k Miles Engine: 4.0 Trans: Auto Transfer Case: Not sure Front Axles: D30 with CAD Rear Axles: D44 WheelBase: Not sure - stock short bed. Build date: Not sure, door sticker in bad shape Current Location: Kansas City, MO Status: Is it still on the road, lots of rust(body and frame), starting the restore process Current owner: Rob Ward

Appreciate all the input, will keep pushing along with the project. Luck I found this forum with so much great info about Comanches. Finally got the hubs off, its amazing how much persuasion an 8lb hammer and a Bearing Hub Removal Tool has. Of course today I learned what a D30 CAD axle is. Wasn't expecting two short axles shafts when I pulled them. Going to replace the driver side front axle shaft for now since I can't get the spindle nut off the shaft, passenger one is in good shape. Picking up the rest of the front in parts tomorrow, but going to clean up the axle before I proceed. Will drop the VIN in the registry now. Keep forgetting Adam's Polishes Actually have a torch, but haven't used in years, just need to get the tanks refilled. I am sure it will come in handy soon with this truck.

Bought my 1989 Jeep Comanche Pioneer 4x4 Auto with 4.0L with 189k on it 2 months ago today. Had looked at multiple comanches trying to find one to repair/restore, choose what I thought was the best of my options at the time. Now I am wondering if I made a horrible mistake. Have no real life friends so I have no one to slap me the back of the head and tell me I am an idiot. Looking for some advise on if I should keep pushing ahead or admit I made a mistake and its time to take old yeller out back. I know this comanche had alot of rust, body and part of the cab floor need alot of repairs. Frame was pretty rusty but couldn't find any holes on this one, others had holes in the frame or other damage, so was hoping to clean it up the frame. Engine runs good even has working A/C, and besides the No Start Issue that turned out to be the fuel pump coming disconnected inside the tank, when I got it home, the engine seems solid enough. Purchased it and drove it home 500+ miles. Had no issues except the weak brakes. Rear brakes had a leak, and the load sensing valve was not working, so failed state inspection and had to have a shop do some repairs to get it approved. Brakes now work but are still very weak . While trying to fix the brakes, found the front has not been bleed for years and may not be working well and everything on the axle is rusted shut. Bleeders snapped off. Was going to take it all apart, replace the calipers, rotors, etc.... But it keeps getting worse. The passenger side came apart easy, caliper came off, rotor came right off. The driver side, caliper came off easy, but rotor was rusted on and the edges of the rotor looked in bad shape, had to beat the rotor off. The dust cover on both sides is completely rusted apart, passenger dust cover is 1/2 still there, the driver side is all rusted away, only pieces left. Decided to pull the hubs so I could clean everything up and replace the dust covers... but that is were the fun stopped or started, depends on your perspective. The hubs are rusted to the axle or at least the knuckle. On the passenger side, got the axle nut off easy, took off the 3 hub bolts off and the hub will not come off. The driver side is worse, can't even get the axle nut off, an impact and 4ft breaker bar and it won't move. And the driver side has the same hub issue, all 3 hub bolts are out and hub is just rusted to the axle/steering knuckles. Have sprayed alot of pb blaster and used many methods of persuasion, and I can't get either hubs off. Guess I can try just taking the knuckle off, with everything still attached... never tried that, not sure it would work. Now I am questioning if all this work is going to be worth it. Is the axle going to have even more rust related issues even if I work past the hub/brake issues. If I go find another axle to swap it out for, am I just putting a good axle on a rusty pos that needs to be taken out back. Picture is from the day I got it home, back when the brakes were even worse and a picture of the front, you can see the rusted out dust cover. But its a good shots of the rust.

Yep, one bleeder snapped off, and the other side looked worse so I didnt even try. Already ordered new calipers and a few other parts(pins, bushing, dust covers) that look worn out and old.

Well started to pull the front brakes apart. Front pads and rotors look great, almost like they are new and unused... Everything else is rusty. Decided to try bleeding the front brakes. Looks like the brake bleeders on the front calipers haven't been touched in years and are rusted to the caliper. So the shop was supposed to change out the break fluid definitely didn't bleed the front brakes. Going to pull the calipers and repair/rebuild them and then re-bleed all 4 brakes and see if anything changes.

The valve just under the master cylinder looks alot like the XJ one I am seeing online. It has some wires going to it. Not sure if this is stock on the MJ or something that was added. Not sure what the wires are going to, will try to trace them. Could this be a proportion valve but maybe its not hooked up so I am not getting proper brake balance?

Great write-ups on what you have done to your comanche, I like the changes you did to the brake line setup, I may attempt to do something similar. Yep, the rubber line will need to be replaced when I put on a lift, its way to short. Call the shop earlier today, they changed nothing up front, everything they did was in the rear, starting with the brake lines near the fuel tank and back.

Picture of booster and master cylinder attached. Only other valve I could find is just under the master cylinder, traced all lines back to it and it is hooked to the master cylinder. Tried to take a picture of it but its hard to photograph it. There is a wire plug coming out of it.

Inspection said front brake were at 12mm, but will be pulling it apart tonight to start checking myself. Hoping it is just the front brakes.

I will trace the brake lines and see what I can find.

Looks like the brake line goes to a simple distribution block on the axle. Took a quick picture.

My 1989 Jeep Comanche Pioneer 4x4. 4.0 has a brake problem. Back story Got my comanche just over a month ago. Brake were terrible, felt like rear brake were not engaging. The bed load brake thing, I can't find the name for it, was broken and leaking, so don't believe rear brakes where getting much pressure/fluid. Failed state inspection because of this. Had a local show shop hard line the rear, so the bed weight brake thing isn't hooked up anymore, I also removed it from the bed. Rear brakes where also worn out. Had rear drums replaced and new rear pads installed. They also replaced all the brake fluid, fluid appeared very dirty. Got it back from the shop. Brakes felt a little better... but still horrible. Brake pedal has alot of dead space / spongy before the brakes engage, feels like I am push 80% down before it engages. Last 20% fells good, jeep stops, but after stopping it wants to lurch forward, keep having to push a bit harder to make it not roll forward. The previous owner did mention he replaced the master cylinder at some point. Test Plan Since rear brake are all new, I plan to start by looking at the front brake, maybe bleed the brakes myself to make sure there is no air. Brake fluid reservoir is full and I don't see any leaks. Usually spongy brakes have been air in lines issue or master cylinder issue, but I am no expert. Just looking for any advise/recommendations of things I can check to identify the issue and fix it.

Only had the Comanche for just over a month, not sure if the fuel pump has been replaced or not, would assume so, seems like common part that dies. Hopefully the hose is the proper hose. But if it comes off again I will check it. Thanks for the heads up.

Yep, that was the problem. Glad someone could pick on the pump not sounding right on the video. Drained 5 gallons from the tank, since I know it we pretty full and then popped the fuel pump out. Sure enough, hose was disconnected in the fuel tank on the fuel pump. Reconnected, move the hose a bit higher than it was previously put on, hope it stays better. Jeep fired right up, took it for a short drive and everything is back to normal. Thanks @fiatslug87 @Eagle_SX4 @Bhase @llhat and all the others who helped me diagnose the issue. Learned a lot, hope to learn a lot more as I work on restoring, fixing, and modifying my Comanche.

Video of fuel Pump, sounds to me like its coming on. Hopefully I am correct. Also have video of it firing up with start fluid sprayed in it, don't think it adds much info. 20250803_175917.mp4

Correct, if i put spray starter fluid directly into the throttle body it starts and run for a second or two. Without starter fluid it just cranks and engine doesn't start. Jumping the fuel pump ballast resistor didn't change the results with or without starter fluid. Got a R.E.M.II+ from NickInTimeDesign today. Plugged it in to get some readings. Still learning all the workings of the REM but below are some screens from the diagnostic section, not sure if they help at all. Only tried starting it without starer fluid to get readings. Didn't try putting in starter fluid so that It would run for a few seconds, not sure if that would results in different/altered data. Did see a message saying No CPS signal, not sure if I should put old cps back since it may not have help swapping it out. Current next steps I plan to test/try. Unless I should try something else first. Check if fuel pump is coming on, hard for me to hear over the ignition buzzer. Got under the jeep last time while some turn the ignition to the start position and pretty sure I head the fuel pump. Just waiting on an extra set of hand so I can retest. Check fuel pump ground by tail lights. I did swap out the tail lights weeks ago, have driven it many times since, but will check to make sure it still good and attached, may move as per recommendation once I get it running again. Checking fuel rail pressure, don't have pressure gauge I can use for this, getting one today Ordered a fuel filter, may or may not change it out depending on results of other test.

Went and got some new start fluid, sprayed in throttle body and it turns over for a second. Guess i need to recheck pump, maybe replace fuel filter, existing one looks ancient and research which relays to check. Its progress 😁

Greatly appreciate the help. Rotor is spinning when i crank it, even saw a spark from the center on the distributor cap.