Eagle

One of the genuine mysteries about DW is how you can never adequately explain it to someone who has never experienced it ... and there's no need to explain it to someone who HAS experienced it.

Sure, you can have wheel shimmy that doesn't develop into DW. I've driven thousands of miles with slight shimmy. That's why I know it isn't DW -- 'cause I've also had the real deal. Makes me crazy when I see kids on NAXJA blathering about "verge of death wobble." WTF is "verge of" death wobble? Either it is ... or it isn't. It's a harmonic because if the initiating shake or shimmy doesn't/can't induce a corresponding shake in the other wheel at the same frequncy, it doesn't escalate into DW. My first DW experience was in a box stock '99 WJ. Word is that the '99 WJs with export suspension had a horrible DW problem, but the standard US suspension didn't. Why? Different spring rate and shock valving. The export suspension happened to match the natural frequency of the spring with the bounce rate of a warped brake rotor at 57 MPH. Once you hit the harmonic, the oscillations become mutually reinforcing rather than mutally cancelling, and THAT's what DW is. My WJ had the optional suspension, which I believe either was the same as or was very close to the export suspension.

Sorry, but I very strongly disagree. Death wobble has exactly NOTHING to do with noise, vibration and harshness, and there are NO degrees of death wobble. Either you have death wobble, or you don't have death wobble. Period.

Grab a tall, cool one and settle in for a lengthy explanation. The MJ has two rear brake circuits. The "normal" circuit feeds out of the nose of the metering block and runs through the rear proportioning valve. If you have no brake problems, the rears are always fed through the rear proportioning valve. The second line, off the bottom of the metering block, is often called a "return" line. It isn't. It's a bypass line. If you lose the front brakes, the same plunger in the metering block that triggers the brake system warning light also opens a passageway that allows fluid to flow through that bottom outlet. That one bypasses the rear proportioning valve and delivers full pressure to the rear brakes at all times. But ... under normal conditions there is NO FLUID flowing through that bottom outlet. Plugging the outlet at the nose and just leaving the line out of the bottom will give you a hard feeling peddle, but you won't have any rear brakes. Don't ask me how I know this.

I don't know if they have improved, but a couple to three years ago Rough Country had a reputation for their front COIL springs breaking. I wouldn't put Rough Country in one of my vehicles if it was given to me.

Those center caps also came with either silver or gold lettering, so there are at least two different part numbers for a cap that will fit, depending on which color you want.

No wiring on the cat for an '88 MJ. I don't trust the XJ proportioning valves. The rear circuit clogs up and you have no (or very weak) rear brakes. Plug the front, bottom outlet on the MJ metering block, and run from the "nose" outlet (the one where Pete's pic has a black plug) directly to the hose at the rear axle. If you're asking can you use the "spreader bar" (dunno if that's the official term) from an XJ on an MJ, I would think so but I haven't compared them so I am not certain.

Just what Cwlongshot said -- steering damper does NOT fix death wobble. We need more specifics. What speeds? "Over 30" doesn't help much -- how much over 30? 40? 50? 65? What kind of bumps? Gentle bumps like good speed bumps, or sharp whacks like potholes? Have you checked the wheel rims for runout? Have you checked the lugnuts to ensure that they are correctly torqued? What kind of shock absorbers are you running and how old are they? What are you running for front springs, stock or some after-market lift spring? If after-market, whose and what height and spring rate? DW is not easy to track down. The problem is that it's a harmonic, and there are any number of factors that can set it off, but they may not be the ultimate "cause." I've had it in a box stock Grand Cherokee, and I've had it in one of the MJs. Never found out for 100% certain what the "cause" was in either vehicle, but in each case it only happened one time. With the Grand, it simply never happened again ... I didn't change a thing. On the MJ, I swapped on a different set of tires and never had DW again (so far).

The above posts have covered it pretty well. As noted, the front "thingie" on the MJ is not a proportioning valve, it's just a distribution block with the brake system warning plunger switch in it. That thing in the back that the rod goes to from the differential is the proportioning valve. I recommend eliminating the rear proportioning valve. The one on my '88 BLEW OUT when I had to make a panic stop. That, as they say, is not a good thing. And the idea of swapping in a Cherokee front proportioning valve sounds great in theory (it is a bolt-in swap), but the reality is that the Cherokee proportioning valves are notorious for getting gummed up and resulting in ... no rear brakes. IMHO, I favor just eliminating the circuit that runs to the rear proportioning valve. Plug the outlet on the front bottom of the stock MJ metering block, and run a new line directly from the outlet in the "nose" of the block directly to the rear axle. Yes, it will possibly cause early rear wheel lock-up in a panic situation, but at least you'll have rear brakes. You can alleviate that to an extent by using rear wheel cylinders with a smaller diameter piston.

Unfortunately, we also have an eagle being threatened that he'd better pay his bills, as well as get the "junk" out of the yard. Honestly, non-Jeep people can be SOOOOOO unfeeling. Despite the fact that I periodically wrench on the hulks, the neighborhood busy-body persists in telling the zoning officer that I have "unused" vehicles in my yard. I'm tempted, but between 600 clams and several hundred miles to fetch it, I can't ante up this time.

The basic axle is the same on an '86 but some early Cherokees used CV joints at the outer axles rather than u-joints. They'll work, but when they go bad they are expensive to repair. At that point, it's cheaper to buy a pair of used inner and outer shafts set up for u-joints. See my other post regarding brakes. Those aren't the same. (Hint -- the 86 rotors don't warp like the 90 ones do.)

I carried a 31-10.50R15 in the stock, under-bed location. I think that's the limit for size, and I was a little worried about that much weight on the winch cable but it didn't seem to be a problem. 235/75R15s will be no problem at all.

Don't try to use rotors, hubs or calipers off the 90 on the 86 axle. They aren't the same. If you use the 86 axle, it'll bolt right in but you have to use hubs, rotors and brake parts for the year of the axle, not for the year of the chassis.

Others have had similar symptoms, myself included. On the '88 MJ, the turns worked fine during daylight, but at night the left front parking light was dim, and the left turn indicator lamp on the dashboard always glowed when the lights were turned on. The problem was the typical bad ground in the parking light socket, causing the parking light filament in the bulb to seek a ground the only place it could find one -- by back-feeding through the turn signal circuit to the dashboard ground. I replaced the socket a few days ago. Tonight was the first time I've driven it at night since the repair, and the problem is GONE! No more glowing lights on the dashboard. BTW -- let me stress that the bad ground is IN the socket, not in the ground wiring from the socket to the chassis. You can find a replacement socket at any of the parts chains. It won't say it's for a Cherokee/Comanche. I think the one that fits is for a Ford. Take your parking light housing into the store and match up a socket that fits.

Not quite. They are wired in parallel, otherwise they wouldn't each be getting 12 volts. What tells the indicator a bulb is burned out is the flasher. The standard flasher unit (if you don't have a tow package) is what's called a "load-sensing" type flasher. It's calibrated to flash at the normal rate when all the bulbs are pulling juice. When a bulb burns out, the filament breaks and current no longer flows through that bulb. This changes the amount of current the flasher carries, which alters the flash rate. The opposite is if you connect a trailer to a standard flasher, it carries 50% more load -- that's why many times you'll see cars pulling U-Haul trailers with turn signals that flash very quick and short. The heavy duty flashers used with tow packages are not load-sensing types. They are more durable, but they flash at the same rate whether you have four, six, eight, or just one bulb working. Which means if you run a heavy duty flasher (which I always do), you have to periodically check your turn signals and hazard lights because there won't be any indication of a burned out bulb on the dashboard.

If it was hit hard enough to mangle the front axle, you'll want to check to be sure the front of the crankshaft wasn't hit hard enough to damage the engine, and you'll also want to check the front unibody extension rails to be sure they haven't been bent out of position. Your best solution for parts is to buy a beater XJ of similar vintage, take what you need, and sell the remaining parts to recoup the cost of the donor vehicle.

The fuel pump ballast resistor isn't necessary, it's only to make the fuel pump run quieter. The 87s don't have it. Which means for diagnostic purposes you can just jumper the two wires together. If it starts and stays running, you've identified the problem. Since you changed the air filter, there's a good chance you may have whacked that thing without realizing it.

You'll also need to drill and tap a hole in the back corner of the head for the temperature sender. The 99 sender in the thermostat housing sends data to the PCM and the gauges pull their data from the data bus. The '91 gauge is driven directly by the sensor in the head.

That's the correct plate. The paint code is two letters and a number. Colorado Red, for example, I think is PE9 (going from memory).

Chrysler dropped the vacuum disconnect beginning in either 91 or 92, so any XJ or MJ 231 t-case from 92 and newer will be free of the vacuum switch.

I'd feel a lot more confidence if they could spell "enclosure" correctly on their web site. Sheesh!

Your '87 has the Renix throttle-body injection. Anything for '91 and newer will be set up for the Chrysler multi-port injection. The basic short block *should* be the same, but externals and manifolds will be different.

My point was that they stopped using the rocking chair seats in the XJ around 1989 or 1990. Chrysler didn't want to spend the money. I think any XJ bucket out of a '90 or newer (maybe '91) that doesn't have the rocking chair option will be a better fit.

????? I didn't know there was an '88 Eliminator. I thought that didn't show up until 1990.

If you look closely at the diagrams Pete posted, you'll see that the XJ "curved" seat base (the one used with the "rocking chair" option") has a shoter pedestal than the one for the "straight" XJ seat. I need to confirm with some actual seats, but I think that means if you put a rocking chair seat onto an MJ pedestal and keep the rocker mechanism, you're going to have a seat that's several inches too high. Either get XJ seats out of a vehicle that doesn't have the rocking chair bases, or remove the seat from the rocking chair and mount it directly to the tracks.