AZJeff

The easiest fix is to obtain a bunch of rolls of appropriate wire in guages that are at least as heavy as the OEM. Multiple colors will help, as will a wiring diagram for your model year. Do this one at a time: 1. Cut out the burnt/melted wire at each end of the damaged area. 2. Using a wire of gauge the same or maybe one size larger, splice in a replacement wire to replace the cut section. 3. DO NOT use butt splice crimp connectors. I have seen too many of those wind up creating high resistance connections that causes further wiring melting. 4. Either use solder-type butt splices that use low temperature solder (that can be activated by a heat gun) or do the old fashioned solder and heat shrink tubing to restore each connection. I know this sounds like a PITA, but early XJ/MJ wiring was sorta marginal, and fixing wires that were flakey with improved current carrying capacity (and reduced chances of heat damage) is a good thing. My fuel injector harness on my XJ HO engine developed this issue due to engine heat, and after I discovered how pervasive the damage was, I bit the bullet and fixed all the suspect wires. Underhood (or under dash) wiring fires are no joke.

What is driving the need for a replacement harness? Broken/chafed wires, or trashed connectors?

That’s a solid plan.

I assume you are referring to the manifolds on the 4.0, because they are larger. I find installing the exhaust first LOOSELY and then fitting the intake works best. i also ditch the stupid OEM manifold bolts for all of the lower attachment points, and instead use studs and nuts. It makes alignment about a million times easier. The only ones I retain with the OEM bolts are the upper ones that attach the intake only in between cylinders 2 and 3 and between cylinders 4 and 5.

Here is a really detailed explanation of how to rebuild your GM tilt mechanism to work like new again. Fixing a loose tilt column

That is correct. I did this to my MJ about 8 years ago, and it makes a MUCH cleaner installation, and eliminates the potential for rusting where the bright metal trim would rub/vibrate on the painted edge of the glass opening.

The clips are ONLY used on the windshield trim when using the bright metal trim pieces. If you are using the one-piece rubber surround trim, no clips are needed. i would be concerned that your glass installer doesn’t know what he is doing if he thinks he needs metal clips to install a windshield with the rubber surround.

Any junkyard with a 4.0 from an XJ or MJ will fit the bill.

A quick search showed several suppliers who carry this one

It’s odd that your glass guy does not have a line on that rubber surround, given that the seal often becomes permanently bonded to the glass during installation and must be replaced when new glass is installed. A clarification here: that rubber piece is NOT a gasket or seal. Its presence (or lack thereof) will play NO PART in making the glass-to-body joint waterproof. That rubber piece is there strictly to fill the gap between the edge of the glass and the opening in the body shell.

Safelite is a bunch of idiots, obviously. The only real difference in the windshield between the 97+ XJ and the older MJ/XJ is that the later style has a rubber gasket that slips over the end of the glass and surrounds its perimeter, whereas the older style had separate metal trim pieces that covered the gap between the edge of the glass and the body. The actual method of attachment of the windshield to the opening in the body of the vehicle is identical in both variants and employs the usual urethane adhesive. In actual terms of installation, that the rubber gasket, even when present in an original installation, often is permanently bonded to the old glass with excess adhesive, and cannot be reused. That means having a replacement rubber gasket is always prudent if you are the glass installer.

I HIGHLY encourage you to do this whenever you have a mystery coolant loss. It’s about as definitive as it gets, and will give you an answer (via an emailed report) in a few days.

Given that any belt you obtain that is second hand is over 40years old, I would encourage you to purchase a NEW seat belt instead. The old fabric is probably badly sun faded and thus deteriorated and of low strength compared to new. There are LOTs of companies that make replacement seatbelts in colors that will come close to matching your interior. Do a search online.

On most unibody vehicles, the rocker panels comprise a significant part of the longitudinal stiffness of the chassis structure. That is NOT the case on the MJ/XJ vehicles, as they have a boxed rail under the floor pan that constitutes a type of integral frame rail down the length of the chassis. because of this, I recommend fixing the floor pans to increase overall longitudinal stiffness before attacking the rocker panels (which are more cosmetic on the XJ/MJ)

That is a good point. Due to me being in AZ, and having a Comanche that lived it's life in a relatively benign environment, I have never had those worries.

I cannot understand why a glass shop would not do work on an MJ "due to its age". The glass is attached to the body with the same urethane adhesive an almost all other vehicles. The only variation from newer vehicles is the use of the chrome trim around the glass/body joint, and that is merely held on by clips attached to welded studs on the body. As others mentioned, converting to the new style glass trim (97+ XJ type) eliminates the chrome trim pieces, and makes glass installation that much easier.

The AC system for the MJ is identical to that for the XJ, so the system is sized to cool the vehicle with the larger internal volume and greater glass area. This means that it’s actually oversized for the job in the MJ. Converting an MJ to use R134a will, in theory, will reduce its overall cooling capacity. In practice, the extra margin in the MJ’s AC cooling ability makes this pretty negligible.

Any time a heater core is found to be plugged up, it’s a sign that the cooling system has not been well-maintained somewhere in the vehicle’s past. That, in turn, indicates that the radiator is, at the very least, not in OEM condition (unless it was previously replaced due to blockage.) if I see a plugged heater core, I immediately assume the radiator is in need of replacement. The XJ and MJ series of vehicles are NOT tolerant of cooling systems that are in any condition except like new in terms of performance, as the design has VERY little margin for deterioration.

There is absolutely NOTHING wrong with a Timken bearing made in a facility other than the USA. Timken has had production operations in multiple countries outside the US, and they all build products to the same standard for that particular bearing. Any claims of evidence that Timken parts made in “country X” that is not the USA is strictly anecdotal, with no statistical backing to such claims.

If you use a Remflex manifold gasket, they recommend tightening the bolts/nuts to a specific amount of gasket COMPRESSION, rather than fastener torque. this means conventional sockets/ratchets/ extensions can be used to install the manifolds and the Remflex gasket. No torque wrench needed. best of all, they won’t lead like OEM style gasket.

Here is what one of the Oracle lights looks like installed on my MJ.

I did a set of Key Parts lenses, and they are HUGE improvement over chalky 40 year old OEM ones. However, the original taillights on the MJ are pretty lame in terms of brightness, especially in daylight conditions. I have this overwhelming fear of some idiot here in AZ not paying attention and running into the back of my truck. With that in mind, I forked out the coin for the Oracle lights, and could not be happier, as they are markedly brighter than the OEM ones.

I have only seen pictures of a pre-1997 heater box disassembled, as the only ones I have ever torn apart came from 97+ XJ's. From what I remember, the actual heater box on the later design is physically different than the earlier design, which means the heater core and evaporator cores probably are different as well. Renix heater/evaporator cores should be the same as the later (pre-97) ones, as they did not change the heater box, to the best of my knowledge, and that would make the suggestion of@eaglescout526 viable.

Are you trying to use the evaporator from a 97+ XJ in your MJ? If so, doesn’t that require the use of the corresponding heater box?

With factory ride height suspension, you will need to undo the lower front shock attaching points to allow the axle to drop further and allow the oil pan to come free. Once you have 3 inches or more of suspension lift, dropping the front shock mounts is not needed to get the pan out, but it makes it easier the more axle compliance you can get