Eagle

Not sure, but I think someone once mentioned that the long beds have more room underneath for the spare. I don't currently have any long beds, so I can't compare. I used to carry a 31x10.50 under the '88 short bed, and it seemed to me that was a pretty tight fit. MAYBE I could have gotten a 32 in there ... I'm sure I couldn't have gotten a 33 in.

Many of us would go through the effort, just for the "cool" factor. Plus, it was a rare, factory option (on the XJ). It would be a crime to let a known example go to the crusher. "They don't make 'em like that any more."

Long bed or short bed?

I have to disagree. The factory had so many problem with the donut spares and limited slip differentials that they long ago stopped using the donuts in vehicles with a limited slip. The limited slip vehicles always came with a full-size spare. The size difference causes rapid wear on the clutches. This would not be a problem with a TrueTrac, gear-type limited slip, but I don't know how that type would react to different size tires. Probably one tire size difference wouldn't be an issue, but a 33 with a 31 or a 30? I would be cautious about trying that.

Do you happen to have a pic of the fluid sentinel. Never heard of it and wondering what it would look like Here ya go: It was actually called "System Sentry," not fluid sentinel.

Once you lock the CAD (Central Axle Disconnect) in the engaged position, you no longer need the vacuum harness down at the axle. Trace it back up to the point shown in your upper photo, unplug it, and plug the lines it connected to. That should allow your vacuum switch to function, and the light should work.

You don't really have much choice about keeping the left side panel -- it's an integral part of the dash cluster. See photo in the first post of this thread: http://comancheclub.com/topic/51819-tach-not-working/

Everything about Hornbrod's MJ is either shiny or black. He's like that -- a thoroughly despicable person. :thumbsup:

1) Be sure to put lots of old rags under the master cylinder before you start removing those lines. Brake fluid will drip out, and brake fluid eats through automotive paint in a nanosecond. You do NOT want to let any brake fluid touch your paint -- not even in the engine compartment, under the hood. 2) The master cylinder is held to the booster by two nuts. If you are replacing both the master and the booster, you don't even need to remove those. You can remove the booster and the master cylinder together. 3) The brake booster is attached to the firewall with four nuts. There is a pushrod from the booster through the firewall that attaches to the brake peddle. That pushrod should be fixed into the piston in the master cylinder, so you'll need to disconnect it from the peddle so it can go out through the hole in the firewall when you remove the booster. 4) It's easy to round off those nuts attaching the steel brake lines to the master cylinder. Do you have a set of brake line wrenches? If not, this would be a good time to invest in them. Your truck is 30 years old -- you'll be doing more brake work before you're finished. They look like this. You can get them at Sears or NAPA, and I guess at the other auto parts chains. Harbor Freight also has them, but I wouldn't trust them.

No. Jeep stopped using the axle disconnect in the early 90s. Locking the disconnect in the connected position just means the front driveshaft will turn (free wheeling) when the vehicle is moving, but the front driveshaft will NOT be connected to the transmission and engine unless you shift the transfer case into 4WD.

Looks like you have Command-Trac, which is the basic 4WD system. That would be an NP207 transfer case. In 1986, both the Command-Trac and Selec-Trac systems used a vacuum disconnect on the front axle, to disengage the front drive shaft from the wheels in 2WD. There's a vacuum harness that activates the shift motor, which is on the passenger side axle tube. If that vacuum harness has a vacuum leak, (1) you won't get 4WD even with the shift lever in 4WD, and (2) the light won't come on because the switch is operated by vacuum.

No. Go to the D.I.Y. area of the forum and you'll find an article on how to remove it. It's not as simple as it seems, because it involves the total removal of one of the two brake lines from the front to the rear -- and many people remove the wrong one before they figure out the mistake. If you remove it, you will always have FULL brake power to the rear wheels. That might sound like a good thing, but the back of a pickup is pretty light when there's no load, so on snow or ice, or in a panic stop, or even in the rain, the rear wheels will lock up before the fronts. That causes spin-outs. That's why the factory put that thing in there. You would be better advised to fix up a rod and connect it so it functions properly.

That right there is grounds for a lifetime ban from the Comanche Club. :laughin: :banana: :yes:

Flip down the driver's side sun visor. There should be a sticker on the top that tells you which transfer case you have. If not, post a photo of your center console, showing the shifters. If you don't mind getting dirty, there should be a round tag on the transfer case itself. It'll have a model number on it. You're looking for NP207, NP228, or NP 229.

Did you click the link I provided? That tire in the photo is not the driver's side tire, it's the spare.

Here ya go: This doesn't show the axle end, but this is what the arm should look like when connected. Even better: http://comancheclub.com/topic/45839-mj-height-sensing-brake-proportioning-valve-adjustment-procedure/

No, it's swinging across the vehicle centerline, correct? You wrote that it swings left to right. The basic position for it should be swung to the right (passenger side) and up, so the arm is parallel to the ground.

You have an '86, which is pretty much a unique animal. Your transfer case could be one of two, and for the MJ those two were used ONLY in 1986. Do you have Command-Trac or Selec-Trac? You're saying the light doesn't come on when 4WD is engaged, but the whole purpose of the light is to tell you when 4WD is engaged. If the light isn't coming on -- are you certain the light is the problem? How have you verified that 4WD has really engaged? BTW -- your photo of the right side panel seems to show a clock. You might want to reconsider drilling holes in it -- you might destroy the clock circuit board (I'm not sure how much space it uses internally). You have a full gauge cluster -- what other gauges do you want?

That's the load sensing (or height sensing) proportioning valve for the rear brakes. The purpose is to reduce pressure to the rear brakes when the truck isn't loaded, so the rear brakes don't lock up too soon and cause you to spin out. As the bed is loaded, the bed drops relative to the axle, causing the arm to move and increase the amount of pressure to the rear brakes. However, that swinging arm is supposed to be horizontal, and there should be a connector link to a ball stud on the differential housing. Yours appears to have been disconnected by some previous owner. There are photos in other threads here that show how it's supposed to look. Do some poking around in this discussion area and the D.I.Y. area, or maybe someone who remembers where to find the photos will jump in with a link.

Good news that he got it working. If the "new" cluster came from a 6-cylinder, the tach probably doesn't read correcttly. The good news is that that style cluster is the newer style ("newer" as it relates to the Renix years, with the mechanical speedometer), and those have a potentiometer on the back of the tachometer that can be used to adjust it to read correctly for a 4-cylinder. If it came from a 4-cylinder, no adjustment should be required.

https://www.napaonline.com/napa/en/search/?text=Brake%20master%20cylinder&isApplication=true&isInterchange=true&referer=herofitmentForm-newveh#

The tachometer is electronic, not mechanical. It receives electrical pulses and "counts" them, converting that into an RPM reading. The electrical pulses for the tachometer come from the ignition. What it's doing is counting how many times the coil sends a spark to the spark plugs.

It will 'work' even if it's the wrong one. It just reads incorrectly. ^^^ What he said.

There's an entire forum dedicated to the 4.0L stroker engines. I've lost the link to it but I'm sure Hornbrod has it.

If I remember correctly, there are two contacts where the tach head attaches to the printed circuit. Under the hood, there are two small, yellow "thingies" (highly technical term there) with flip caps on them. Inside, there are contacts for running some basic diagnostics. The smaller of the two has six terminals (receptacles). That's the one with the feed for testing the tach. You can check it by taking the cluster out of the dashboard and running jumpers from the test terminals to the tach head. I'm not set up to scan the diagram of the diagnostic connector. As drawn, it shows two columns and three rows. The right side of the block has two notches cut out of it. Oriented that way, top right is #1, #2 below that, #3 bottom right ... then #4 top left, #5 below that, and #6 bottom left. #1 is the positive tach feed. #3 is the ECU ground -- you can use that for the tach ground, or just ground it to the engine block.