Eagle

Well, here it is, then:

The most common cause of sudden failures to start is the CPS (crank position sensor).

Problem is, the customary way to stroke a 4.0L engine is to use a 258 crank. Even with NO overbore that brings it to 4.5L, which is 274.5 c.i.d. So you're really stuck with either using a 4.0L at maximum overbore and as much offset as you can grind into the crank, or starting with a 258 and running minimal overbore to stay under the maximum displacement. The 4.0L has by far the stronger rods and better breathing head and manifolds, so IMHO that's the way to go, even if you're under the maximum displacement. Anyhoo, a smaller bore and longer stroke is not the optimum setup for maximum horsepower and RPM. I'd recommend staying with a standard-stroke 4.0L and a maximum bore of .060 over. You might get more on the bore, but it'll reduce cooling efficiency and exponentially increase the likelihood of an engine failure -- if you don't punch through the walls while trying to bore it. Although I like the Renix setup, the newer heads and manifolds flow better and the HO puts out more HP (in stock trim) than the Renix. So I'd suggest perhaps converting to an HO ignition and injection. Among other things, I believe you can get power chips for the HO -- they aren't available for the Renix.

Good call -- if it's an '86, it won't hae the Dana 44, and those pics of the rear diff certainly look like it might be an AMC Model 20, but there's no straight-on shot from the rear so it's hard to tell. If the cover is a perfect circle, rather than an irregular hexagon, it's a Model 20. However, that's nothing to sneeze at. It's a VERY tough axle, far superior to the Dana 35 and very nearly as strong as the D44 if not stronger. The major drawbacks are that it's bigger and heavier, so there's a tad less ground clearance under the pumpkin, and you have somewhat fewer options for aftermarket lockers and such. But there are lots of ratios and lockers for the Model 20, so don't pass it up. It'll also have the 10" x 2-1/2" brakes if it's Model 20.

Yeah -- at LEAST 15 or 20 minutes. You were joking, right? WD-40 as a long-term rust preventive? Get serious. WD-40 is nothing but kerosene with a bit of paraffin mixed into it.

I haven't disassembled a door to try it yet, but after considerable research the parts guru at my dealership and I concluded that -- although it isn't listed for manual windows -- it appears that the regulator cable (a.k.a. "snake") for the power windows can also be used in the manual assembly. I have two of them here, just haven't gotten around to trying it out yet. BLHTAZ, got any comments on whether this looks like a possibility? Is the power window "snake" still available as a replacement part? Wait one! I see a pigtail. Those ARE the electric window regulators. The "snake" part should be available as a separate part, unless it has been discontinued.

You can't cut much beyond the holes for the flare brackets. I wish someone had expalined that to the doofus who owned my '88 before me ... :mad:

Correct. My 87 Pioneer grille is all chrome. The 88 Chief is all black, as is the 88 SporTruck. The 88 XJ Pioneer grille is black with silver painted (or light grey, or "argent") accents. Take your pick, unless you're aiming for a historically-accurate restoration.

Take a close look to see if there's room for Monroe Load-Leveler coil-over shocks. They are made specifically for the purpose of handling occasional extra weight without stiffening up the ride. But ... they are usually used in the rear, for vehicles pulling trailers. I don't even know if there's a listing for the front of an MJ. Failing that, I'd suggest ZJ V8 springs, or late model XJ Up Country springs. If you want to go that route, I can get you the part numbers.

XJ brakes will work in an MJ. They are the same ... if they are the same year. What you encountered has been discussed here several times -- Jeep changed the hubs, rotors, calipers and steering knuckles several times during the life span of the XJ (1984 through 2001). One of those changes took place during the MJ's life span, between the 1989 and 1990 model years, and parts between those two years cannot be mixed and matched. If you have a 1990 axle, you have to have 1990 everything ... including rotors and calipers. Once again, here's the run-down. As before, this material is copyrighted by me, and by posting it here I do NOT grant any permission to reuse it, copy it, or reproduce it in any form other than to make ONE printed copy for your own, personal use. ------------------------------------------- Steering knuckles: There are two designs of steering knuckle, and within each design the left and right sides are mirror image and carry different part numbers. The early knuckles were used from 1984 through 1989. The late knuckles were used from 1990 through 2001. Hub/Bearing: Three different hub/bearing assemblies were used. The hub/bearing assembly is the same for both sides of the vehicle. The first type was used from 1984 through 1989, and must be mated to the early steering knuckle from the same range of years. The early hub/rotors used tapered roller bearings, which are available as individual replacement parts, and in theory can be rebuilt. In practice, removing the old bearings and installing new ones requires a large arbor press and bearing splitter, equipment not available to the average owner. In practice, even dealerships simply replace the entire assembly, because the labor cost to rebuild would exceed the cost of a replacement assembly. The second type of hub/bearing assembly was used from 1990 through mid-1999. This hub/bearing assembly mates up with the newer style steering knuckle and is used with composite rotors. Certain years of XJ with composite rotors were subject to a safety recall if they were located in northern “rust belt” states, because of problems with the rotors (see below). When replacing hub/bearings in vehicles within this range of years, unless the vehicle recall history is known it is wise to call a dealer or DaimlerChrysler customer service to determine whether or not the vehicle has undergone the brake rotor recall. If so, confirm which hub/bearing assemblies should be used as service replacements.. The third type of hub/bearing assembly was used from mid-1999 through 2001. This hub/bearing is also used with the new style steering knuckles, and is mated with the newer style cast rotors. Rotors: Three types of rotors were used. Rotors are the same for left and right sides. The first style of rotor was used from 1984 through 1989. The second style of rotor was used from 1990 through mid-1999. This second style rotor was a “composite” design—the braking surface disc was separate from the center “hat” section, which was stamped from comparatively thin sheet steel. After several years of service, it was found that in states and localities where salt is used on the roads in winter, corrosion of the “hat” section could result in the disc portion separating from the assembly, causing a loss of brakes. A factory recall was issued to correct this problem. The recall affects only vehicles within a range of years, and only in certain states. Anyone owning a Cherokee or Comanche in the range from 1990 through 1999 is advised to call a dealer or DaimlerChrysler customer service with the VIN number to determine if the vehicle is subject to this recall. Mid-year in the 1999 model year the front brakes were changed to an all cast rotor design. Although the original, early style rotors were also all cast, the new rotors are different from the early ones and carry a different part number. The new cast rotors were used from mid-1999 through 2001. Because 1999 was a transition year, owners of 1999 Cherokees will need the VIN number to determine the correct parts to order when servicing the front brakes or hub/bearing assemblies. Calipers: Two styles of caliper were used. The calipers are mirror image for the left and right sides and carry different part numbers within each group of years. The early style caliper was used from 1984 through 1989. The later style caliper was used from 1990 through 2001 and is used with both the composite rotors and the newer cast rotors. As previously noted, a complete front axle assembly from any year Cherokee or Comanche can be installed in a Cherokee or Comanche of any other year. It is only when attempting to swap components among different years that the above parts differences become critical.

Vietnam veteran, U.S. Army.

Wow! Never saw anything like THAT before. The '86 MJ I have is a 2WD, which may be different. I'll have to see what other early 4WD XJs or MJs I can find to crawl under. There is nothing like that even mentioned in the FSM. Thank God for AMC (All Makes Combined). Every day brings more surprises.

I pretty much agree with Wade's map, except that I don't consider California to be "southwest," I consider CA to be "west coast." But any map that does NOT include Arizona, New Mexico, Colorado and Utah as part of the southwest is totally lacking in credibility. And Mississippi and Louisiana are part of the "south" not the southwest. How can states EAST of the big muddy be in any way considered "west"?

I dunno, but I'm still leaning toward 2-door XJ.

What transfer case do you have? I'm looking in the 1986 MJ FSM, and it's showing the "rounded fork" retainer just like the one in my 1988 XJ and my 2000 XJ.

The "quill" is the housing at the transfer case end that the plastic speedo gear fits into. No, the gears are the same for all years of the MJ, but the tooth count changes depending on the tire size and gear ratio. As far as I know, all years used a rounded 'Y' shaped yoke to hold the quill into the transfer case.

BEFORE you remove it, clean the area well and take careful note of how it is oriented. The "quill" rotates to adjust for the number of teeth on the speedo drive gear, and if you don't put it back in the same orientation, either the speedo won't work or you'll wear out the plastic gear very quickly.

What year? 86 (and I think part of 87) there's a retaining screw that has to be removed. 88-90 (and at least the last half of 87, if not all of 87) has a white nylon quick disconnect. Pinch the outer ring and it releases the cable from the speedo head.

Eagle,do you think that that valve might be a contributing factor to the all around crap rear brakes from the get go? Becaues mine's still there,and if it'll get me better rear brakes I'll junk it asap. Absolutely. You do know what that rear valve does, right? The theory is that pickups are light in the rear when empty, so without some "outside assistance" the rear brakes would tend to lock up prematurely under heavy braking (panic stops, and maybe even less than full panic mode). But -- when you're loaded, you need all the braking you can get. So, they put in this doohickie that reduces the amount of braking to the rear wheels when the truck is empty, and allows progressively more pressure to the rear as added weight lowers the bed closer to the axle. In fact, the default (unloaded) setting is essentially zero rear brakes, which is why Comanche rear brakes never seem to wear out. I can't tell you how many Comanches I've looked under that had the push rod for the valve disconnected, missing, or installed in a way that clearly would render it unusable. Then there's the fact that the second line to the rear requires a special bleeding procedure that most independent shops probably aren't aware of and thus don't do. My best guess is that 2/3 of the MJs on the road, even if the doohickie is in the truck, don't have a functional rear proportioning valve. So what's the point of keeping it if it can't be serviced, can't be replaced, and nobody has the tools to adjust it? It MUST be adjusted if you lift (or lower) the truck, or it can't function as designed. How many people do that, as opposed to just unhooking the rod and zip tying the lever in a more-or-less horizontal position (thereby forever locking in zero rear brakes)? Get rid of it. If you aren't comfortable with a vehicle that might lock up the rear brakes in a panic stop, go to Summit Racing, buy a Wilwood adjustable proportioning valve, and plumb that into the line leading to your rear wheels.

Reasons to remove the rear proportioning valve: 1) It's an extra steel line running the full length of the chassis. In other words, twice the possibility of a rear brake failure due to corrosion. I patched a rusted section of the primary line, and then had the secndary line burst while bleeding. 2) The rear proportioning valve is now +/- 20 years old, and it has a diaphragm in it. The one in my '88 exploded when I made a panic stop to avoid a doofus octagenarian who cut me off. You can't buy new ones, and I wasn't about to install a 20-year old junkyard part to replace a 20-year old part that had just exploded, so I bypassed it. 3) If you chase down my photo of a cut-open front metering block, you'll see that the one I sliced and diced would NEVER have provided the by-pass, emergency function it is supposed to provide. I have no way of knowing what percentage of them out there may be similarly defective, but any that are would leave you with virtually no rear brakes if you lost the fronts. That's three potentially serious problems. Too many risks for me. I can handle too much brakes in the rear a lot better than I can handle none. When I bit the bullet and replaced the hard line all the way from the front to the rear, I plugged the by-pass port in the metering block, removed the (exploded) proportioning valve, removed BOTH rusted out steel lines and ran a single hard line from the metering block directly to the rear flex hose. I now have decent rear brakes for the first time since I put the truck on the road about 5 or 6 years ago.

Agreed. And eliminate the rear height-sensing proportioning valve while you're doing it. Getting rid of that means about three things less to fail.

Was this the line on the axle, or the line from the front distribution block back to the rear of the chassis?

Have you adjusted the downshift cable?

If you don't have the cluster yet, yeah -- get the cable with the cluster and it should work. Just take the core out of the "new" cable and lube it before you put it in your truck. And be sure to route it so you avoid sharp bends.

No. There are significant differences in hubs, knuckles, rotors and calipers from one "generation" to the next. I've posted the specifics a number of times. I'm sure a search will bring up one of those posts.