jaekl

I'm pulling another post out of the files. Eagle you mention that you were going to check other MJ distribution blocks for the blockage in the bypass outlet. Did you find any? The way your cross section shows it, that vehicle would have a huge air pocket in the bypass line and would never have firm pedal. It could not be bled. If it was made like that, it couldn't have left the factory. Could someone send me the FSM section pertaining to the rear propotioning valve. I had mine apart and I suspect the function is a bit different than the past posts have indicated. Mine is very rusty. Does the fitting at the top come out? If not, it was a bear to manchine. What I'm seeing right now is behind the top fitting is a plunger that is pushed against the opening to close the port. The plunger is held against the opening with a spring that is adjusted by the position of the lever arm. This spring and the small diameter plunger regulates the pressure of the rear lines and responds to accordingly to more right foot forces, but always less than the front pressure with light loads. This would mean the full time pressure would be available at the top fitting, not the side one. I'm confused on the second line. I'm thinking when there is a front brake failure full pressure is available to the side inlet of the proportioning valve and forces the plunger up and closes the inlet, thus allowing full pressure to the drums. The problem is how is this line bled. This line could only be bled by causing a pressure imbalance, front to rear (as stated in FSM?) and cracking the fitting at the prop valve. The function as described in previous post would result in slow (on and off)rear brakes by metering the fluid through a restriction, which is not what is desired. Perhaps if I could read the FSM, I could confirm the function. It definetly looks like I'll be removing the prop valve, but I would like to know how it works first.

I'm a bit late, but I can shed some light on the matter why the brakes locked after the lift. I had my valve apart this weekend. Inside is a cam and a cam follower. It is possible that the cam had rotated enough to be on the back side of the lobe and allowed more pressure to the rear brakes.

Yes, they do work. I did the opposite. I replaced my 2 door Cherokee regulators with front door ones. The rears might work too, but the travel may be shorter.

My oil leak/blow out was a clogged vacuum line. On my 86 it was the one on the front left side of the engine. The metal tube was clogged tight. Oil was coming out everywhere until I opened the vacuum line.

From my experience below, I learned that once the vacuum disconnect is fully engaged then vacuum is connected to the indicator switch. The light only indicates that the right front axle is powered. The transfer case is a good faith operation. I got a real mystery on that vacuum disconnect. I have an 86 Cherokee from new with Command trac. All worked fine for years. Gradually, it took more to disengage the front axle. First slow down, then stopping, and then reversing. One night I took it out of 4wd and as ususal the front axle was still engaged. Before I had a chance to pull over to back up, there was a WHAM. Next time no 4wd. I took out the disconnect and it was jammed in the off position. Forced it back into place and it operated properly, so I put it back together. Next time I needed 4wd, nothing. After studying the vacuum circuit and watching what does what, I ended up pulling two of the vacuum lines out of the plug at the axle and reversing them. Now it works fine. ???????????

A useful hybrid would be to strectch the cab to use a Cherokee 2 door with a short bed on a LWB. Lots of storage in the cab with easy access.

The holes were near the spark plug. I understand the preignition issue, but would it not affect all of the pistons? Also normal ignition is advance already so with extra advance piston farther down the bore. Could it be happening on the exhaust stroke with a superheated plug? I'll have to borrow a strobe light to check the timing.

I have a question to the guys running 4 cylinders. I picked up a 88 Comanche with 104000 miles. Piston #2 and #4 had holes in them. The cylinder wall weren't too bad, so I put two new pistons in and at 115000 it is still running great. I've seen some others with this problem. Is it common? Anybody have an idea what causes it? What does it sound or feel like when it happens? Under what conditions, high rpm or high torque? My 86 XJ has 180000 miles on it with no problems. I was killing time at the dealer in the early nineties and the salesman was shocked that I hadn't had to rebuilt it yet. Great sales pitch.

I know all about the availability of the gauge package. When I was buying my 86 Cherokee, Base with no gauges, I wanted the dealer to put the gauges in. You know the routine, back to the manager, call to the factory, etc. "Can't be done. Maybe $800." I priced the parts over the counter at about $200 and got a wiring diagram and decided it would be a direct plug in as we now know. So off to the junkyard and found a 85 unit and in it went for $50. However, had I looked in the Comanche brochure while I was waiting for their huddle, I would have seen that the gauge package was optional on all models. Where the Cherokee had no gauges available for the Base. The other models all had the gauges but the tach was an option. Got took again. Again brilliant marketing and packaging. There are three different gauge assemblies. No gauge, gaues without tach, and complete. It is not a simple matter to pull the fuel gauge and plug in the tach. You need the full panel. An make sure it is the right year. I found out there was a major design change 85 to 86 so I had a 6 cylinder tach in a 4 cyllinder because the older style tach was much more expensive. Then there was the speedo cable change (87, 88) which is really an entire different gauge panel design. And this is all with the blue face gauges. I don't know about the other type. Bottom line, any Comanche could have a tach.

Just replaced them on my XJ. The problem is the cable. The last 4 inches are rusty and break off. Power windows probably have the same cable. Water gets inside the end of the tube and sits. No ideas on how to prevent and still be assured if water does get in that it will drain out. Leave the windows open half way would keep the cable out of the water. Might cause other problems. 2 door and 4 doors are the same. Didn't check if the rear doors could be donors. The cable comes out easily enough. Just need enough length.

I took another look at the XJ buckets with rockers. What a mess under there. No wonder Chrysler got rid of the rocker option. In order to mount these seats with MJ floor brackets, the tracks from the XJ would have to me completely removed and a bracket is still reguired to reach the holes where the rocker tracks are mounted. The drawing shows it a bit. At this point it is clear why the factory didn't put the rocker option in the MJ. The rear of the seat can't be mounted low enough to put the seat in the best place. My installation is okay, but it is definetly different than the Cherokee. The bottom line is use whatever seats you can find and make your own brackets, just as PingPong said. Only base Jeep bucket seats will fit directly. I have photos of the brackets I modified. I can email them to anyone interested. Or is there some public site I can post them?

After I posted the topic, I took another look under the seat. Since the floor brackets are slanted toward the center of the truck, I assumed that the tracks were mounted in the center of the seats. Not so. The rocker tracks are in the center and the straight tracks are outboard of those. The Comanche bench seat floor bracket offset is to the center of the seat and lines up with the curve rocker mounting bolts. If you want to duplicate a factory mounting, the straight tracks from the Cherokee are needed and then remove the rocker mechanism. The straight tracks should mount to the same holes as the curved tracks. Some adapters may be required. Now the bucket can be mounted to the bench floor brackets and the seat should be at the right location. I've had my Cherokee for 20 years and never moved the rocker position once it was set. That can be done with some spacers. Sure, modifying the Cherokee brackets was a lot of work, but sometimes we need an excuse to tinker in the shop. Therapy you know. Now the question is do I attack the rocker mechanism? Some of those bolts are hard to get at. But then it would be factory design. We all have are own strange reguirements. I'll be taking the seats out again soon to work on the headliner. I'll take some pictures then and post them. If you can't find Comanche brackets, it is a way to go. I quess we all have to prove things for ourselves. I'm convinced that Comanches did use the same floor bracket for both bench and bucket. Now all you have to find is a 2 door Cherokee with the base pedestal bucket without the rocker. Probably easier to find a Comanche with bucket seats.

I might have new information on the subject. Initially, I follow the trend and removed the bench seat brackets and mounted them under Cherokee seats. Sure enough the seats are high and inboard. I have a Cherokee so my goal is to locate the buckets as they are in the Cherokee. I decided to use the Cherokee brackets and modify as required. I decided that the inboard studs are in the same location as the Cherokee but at different heights. I drilled a new hole in the front bracket for the outboard stud. The seats were still one inch too high, but were centered better. I checked my Comanche brochure and there is no mention of the rocker/slider type buckets that Cherokees had, just pedestal buckets. I decided that the front inboard stud is at the same height as a Cherokee, so I used this as my starting point and modified the bottom of the front Cherokee bracket to look like the Comanche bracket. The inner rear needs to be reshaped to get maximum height. The outer rear stud is directly below the track. These brackets were cut and welded to allow access to a bolt. With the slope of the floor, the outer bracket locates the height of the rear, which makes the track fairly level, but the rocker can compensate for that. The end result is great height and centered seats. The problem is that for some reason now the seats run out of travel before they hit the rear window. For my height it is enough. The previous mountings had more travel, but now the seats need to be rocked more to get some slope on the cushion , which moves the set forward. It was a lot of work but I wanted buckets so that I wouldn't be sliding off the edge and to get access to behind the seat without having to get out. The next project is to see if Cherokee 4 door seats can be modified to flip farther.

Both are 1988.

I'm planning a swap a 5 speed from a 4.0 liter to a 2.5 liter with a 4 speed. I know the bell housings will need to be swapped as well, which I believe is possible. The next issue is the input shaft compatibility. Before I pull the trans, can someone confirm that this will work?

Bad ground. Same problem on my 86 Cherokee. My problem was right at the light socket. Power crosses thru the double filament lights and then feeds back up to the turn signal ground in the dash. Fixed mine by flowing solder over the rusting areas. Long term fix of course is to replace.

I'm glad I could help. Now you can come and retape my harness.

They're both located in the main fuse block by your left foot. The turn signal is used as well as the trans. Check all of your fuses.

I can help on this one. Sorting out my acquired 88 I had no back up lights. I was digging into everything. I found that there are two fuses involved. Check the fuse marked trans.

I recently acquired a 88 Comanche to hold me over until I fix the deer damage on my 86 Cherokee. This is a great little truck. I eyed them when I bought my Cherokee new but wished they had an extended cab version. Well now I have both. Since I'm well acquanited with XJ, I only have a simple question at this time. Does anyone have a dealer installed bed liner? I found an unused over the rail liner (with "Comanche" molded in), however, the six mounting holes are below the top rail. Is there a special type of fastener to retain the bed liner? Thanks for any advice.