Wild Comanche Posted November 12, 2023 Share Posted November 12, 2023 I have a 1989 Jeep Comanche 4x4 Pioneer model. Just had a complete brake job performed. New pads, new rotors, rebuilt calipers, 3 new rubber brake hoses, new master cylinder, new brake booster, new shoes, turned drums, new wheel cylinders, new hardware in rear wheels and new self adjusters. Reason is I discovered the brake fluid was black as night. No exaggeration. The brake pedal has about 2 1/2 to 3" of travel before a complete stop. Vehicle doesn't have ABS. It barely locks up the wheels under hard braking on a gravel road. The brakes act like it is not truly power brakes. Something between power brakes and manual brakes. It just is not right. Brakes were much better in years past. Everything has been replaced except the LSPV and the steel brake lines. The brakes were bled using the system explained on Comanche Club. Twice. Fluid is clear coming out of the bleeder ports. And no air. Vehicle has 30" tires. If the LSVP is working properly, should I expect better brake performance with the 30" tires? Thinking of removing the LSPV all together. Seems no one sells a new LSPV. Read that the LSPV could be stuck and is not moving. Maybe I need to remove the LSPV. What steps need to be taken to eliminate the LSPV. Any help will be appreciated...Thanks Link to comment Share on other sites More sharing options...
Pete M Posted November 13, 2023 Share Posted November 13, 2023 what angle is the swing arm at? Link to comment Share on other sites More sharing options...
cruiser54 Posted November 13, 2023 Share Posted November 13, 2023 I've done it twice now. Eliminate the LPSV and distribution block. Add an adjustable proportioning valve. Link to comment Share on other sites More sharing options...
cruiser54 Posted November 13, 2023 Share Posted November 13, 2023 Also, FWIW, I have 2 used LSPVs I removed. Link to comment Share on other sites More sharing options...
AeroNautical Posted November 13, 2023 Share Posted November 13, 2023 45 minutes ago, cruiser54 said: I've done it twice now. Eliminate the LPSV and distribution block. Add an adjustable proportioning valve. Which proportioning valve did you use? Link to comment Share on other sites More sharing options...
cruiser54 Posted November 14, 2023 Share Posted November 14, 2023 https://www.amazon.com/260-8419-Proportioning-Adjustable-Compatible-260-12627/dp/B0CL78FGRF But, that's not all you do to get better brakes. You also eliminate the distro valve on the firewall. Link to comment Share on other sites More sharing options...
Wild Comanche Posted November 14, 2023 Author Share Posted November 14, 2023 Thanks for the input. The swing arm is at roughly a 7:00 o'clock position. The connecting rod from the swing arm to the axle is almost parallel to the ground. After disconnecting the connecting rod, the swing arm moves freely. It might be in working order. This vehicle has little rust under the bed. But the distribution block has not been cleaned and could be crudded up inside. And having a LSPV get destroyed in a panic stop is not good. After reading everything I could find on Comanche Club concerning the LSPV and the distribution block (mounted just below the master cylinder) I am leaning in the direction of eliminating the LSPV and the distribution block and going with an adjustable proportioning valve. And mounting it under the hood where it can be adjusted when necessary. From what I read it would eliminate the brake warning light. I can live with that. Cruiser54's link to the Wilwood #260-8419 260-12627 APV looks good. It has a 5 year warranty for what that is worth. And is only $36.00 on Amazon. If I could still buy a new LSPV and new distribution block, I would probably go that route. But that seems a dead end. Thanks for that link, "cruiser54". I will leave a post as to how the brakes work after installing the APV. Link to comment Share on other sites More sharing options...
Eagle_SX4 Posted November 14, 2023 Share Posted November 14, 2023 The arm should be about the 2:45 position not 7. Here is a thread I started on that. Link to comment Share on other sites More sharing options...
Wild Comanche Posted November 14, 2023 Author Share Posted November 14, 2023 Very interesting. I disconnected the plastic retainer at the ball on the differential and moved the swing arm up and reconnected the plastic retainer. Now the swing arm is in about a 2:45 o'clock position. I wonder how much this affected the rear braking bias being in that previous position? And how long it has been in that position? This is a head scratcher....Thanks for that info Eagle_SX4. Link to comment Share on other sites More sharing options...
Eagle_SX4 Posted November 14, 2023 Share Posted November 14, 2023 I still haven't figured out how it changes the braking but that is how it was set up from the factory. Link to comment Share on other sites More sharing options...
Pete M Posted November 15, 2023 Share Posted November 15, 2023 very common problem. any time the truck is lifted up in the air there's a chance for the little arms to bend the wrong way when it's put down on the ground. seems like a spring should have been used to prevent that. Link to comment Share on other sites More sharing options...
Wild Comanche Posted December 9, 2023 Author Share Posted December 9, 2023 Ended up keeping the distribution valve factory system and pressure bled the brakes. Seems to work OK. Though the brakes are not as good as the best power brake vehicles I have owned, but still good enough. Better than before the brake work. Thanks for all the input. And I still have the factory brake failure warning light in service. Link to comment Share on other sites More sharing options...
gogmorgo Posted December 9, 2023 Share Posted December 9, 2023 On 11/15/2023 at 7:23 AM, Pete M said: very common problem. any time the truck is lifted up in the air there's a chance for the little arms to bend the wrong way when it's put down on the ground. seems like a spring should have been used to prevent that. Has anyone actually observed the linkage inverting with the truck in the air? We suggest it every time but having had my truck on a hoist many times I don’t think it’s something that happens as easily as we suggest it does just having the wheels off the ground. My short bed had the linkage flipped when I bought it and even with the truck in the air there was no way I could flip them back around without popping one of the rod ends off. I would put money on it being someone taking it off to pull the diff cover and then putting it back on without noticing the bar and rod are no longer in the same position as they started. Coupled with how no self-adjusting drum brake ever actually self adjusts, it’s pretty easy to see how it could be missed. Link to comment Share on other sites More sharing options...
Ωhm Posted December 9, 2023 Share Posted December 9, 2023 1 hour ago, gogmorgo said: seems like a spring should have been used to prevent that. The 1990-92 models DO NOT use a spring (5). See thread. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 9, 2023 Share Posted December 9, 2023 The issue with keeping the distro valve is that the front fluid passages in it are HALF the size of the brake tubing and those passages in an XJ proportioning valve. That is exactly why I recommend eliminating the distro valve and replumbing the rear brakes using an adjustable prop valve. Link to comment Share on other sites More sharing options...
zomeizter Posted December 10, 2023 Share Posted December 10, 2023 10 hours ago, Wild Comanche said: Ended up keeping the distribution valve factory system and pressure bled the brakes. Seems to work OK. Though the brakes are not as good as the best power brake vehicles I have owned, but still good enough. Better than before the brake work. Thanks for all the input. And I still have the factory brake failure warning light in service. If you haven't already, pull the rear drums and clean all components with some brake solvent, adjust the shoes till you get some slight drag on the drum, adjust your parking brake while there, enjoy improved brakes... Link to comment Share on other sites More sharing options...
cruiser54 Posted December 10, 2023 Share Posted December 10, 2023 Even better if you adjust them til they stop turning and then back off til they slightly drag. Link to comment Share on other sites More sharing options...
Wild Comanche Posted December 10, 2023 Author Share Posted December 10, 2023 Thanks for the latest input. Those front fluid passages in the distribution valve on an MJ are visually noticeably smaller than the XJ. Maybe the engineers at the factory over thought the problems pickups have with no or light loads in the beds on less than perfect road conditions when braking. And were TOO cautious. Or it was designed in a hurry on a Friday. No body prefers inferior braking when they can have better braking performance. Me included. My MJ is for mountain driving on sometimes snow and ice conditions. I will need to test braking in 4x4 driving on steep downhill grades in the snow before eliminating the distribution valve and re plumbing the rear brakes with an adjustable prop valve. But I can see your point, "cruiser54". Everything in the rear brakes are clean and the shoes are pretty close to being adjusted as close as possible to contact with the drums. This 1989 MJ is still a work in progress....... Thanks for all the input........ Link to comment Share on other sites More sharing options...
cruiser54 Posted December 10, 2023 Share Posted December 10, 2023 I live where it snows right in the mountains at a mile high elevation. They will work just fine. Link to comment Share on other sites More sharing options...
zomeizter Posted December 11, 2023 Share Posted December 11, 2023 I run the valve, did a bunch of ''testing'' with the linkage at different positions to dial in the best rear brakes' behavior with a loaded and empty bed. The things I modified on the system are the MC, I used one off a Ford F100 with a slightly bigger bore, 1 inch IIRC and the discs equipped on the 8.8 swap...Nowhere near the stopping power of hydroboost but I can lock them 31s on steelies easily, I reckon one gets lucky sometimes :) Link to comment Share on other sites More sharing options...
cruiser54 Posted December 12, 2023 Share Posted December 12, 2023 Get some fluid to the front brakes and it will stop better. Link to comment Share on other sites More sharing options...
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