AZJeff

The Chrysler factor gaskets for the 2.5 and 4.0 engines are not the most reliable in sealing the joint. (To put it in other terms, they suck.) I have used Remflex gaskets for years with no issues. Go to their website, and you will find ones for both of the MJ engines there. They are more expensive than OEM types but they don’t leak/fail with age.

I am about 99% certain that, if the control arms are original, the bushings are dried out, cracked and no longer acting like intended. Rock Auto has OEM style, TRW branded bushings for about $5 each. Other brands are somewhat higher or lower. The rub is that you must have some tools to press the bushings out and in of the control arms. (A Harbor Freight ball joint press will work here.) On the other hand, complete control arms are about $25 each. The upside is that it’s more plug and play (upper axle end bushings not withstanding.). The downside is the added cost. I am lazy, so I prefer swapping the whole arm, and using reputable brands.

The photo appears to show clearance for the fuel linebetween both the booster and the inner fender/chassis. If that is the case, there is no need to move the fuel line. if you are really concerned about rubbing/vibration between the fuel line and the surrounding stuff, clip a pice of rubber hose over the fuel line to act as an insulator.

The kit that was cited is from “Detroit Axle” and that is FULL of parts made from “Chinesium”. That means they are bottom of the barrel quality. I would stay away from that garbage and instead, individually source the pieces for the front end from a reputable source such as Rock Auto.

That parts “kit” on Amazon should work, but the quality of those replacement parts might not be “Tier One” OP would be better served by going to Rock Auto and ordering individual pieces from a reputable brand name. It might be more expensive, but the quality (if chosen from a brand name) will be better.

EXCELLENT SUGGESTION. BTW, I assume the OP has slathered all the crank journals with assembly lube or, at the least, motor oil.

Using screw extractors on small screws can be risky. The extractors are very hard (they have to be to “bite” into the broken screw. That also makes them very BRITTLE, and prone to snapping off if not twisted precisely. And once you have one of those broken off inside the screw, you are in a world of hurt. On small stuff like TB screws, drilling them out and retapping for a Helicoil is less risky that a screw extractor.

If you can find a junkyard unit and do a “restoration/refurbishment”, it might be the best solution. Others that are RENIX experts might know: are the what differences exist (if any) between RENIX TB’s and those used on later engines in the MJ/XJ family? Can a later throttle body be used, because if so, then the field of junkyard replacements expands a bunch.

Getting a junkyard unit is certainly a possibility. Even then, they may require “restoration” before installation on your vehicle. I am a guy who normally tries to fix stuff before I rush out to get a replacement, and that is why I suggested the Helicoil approach.

I assume you have removed the throttle body to get better access to the broken screw, as that’s the only way you are going to properly fix the attaching screw hole. The best fix will be to drill out the old screw and install a “Helicoil” to repair the damaged threads. They sell Helicoil repair kits that include the actual Helicoil, plus the requisite drill and tap to install the Helicoil. To install the Helicoil, you will need a drill press, or at the very least, a bench vise to hold the throttle body while using a hand drill to drill out the screw and tap the hole for the Helicoil. Start by using a prick punch to make a dimple as close as possible to the dead center of the exist screw. Then, using a drill bit smaller than the minor diameter of the broken screw, drill down into the screw as straight as possible. Then increase the drill size and repeat until you have the correct hole size for the Helicoil. Then tap the hole using the tap in the kit, and install the Helicoil. now you throttle body is repaired. All you will need is two replacement screws to attach the TPS. I also recommend you use anti-seize compound on the threads of the new screws, so they don’t bind up in the holes in the aluminum throttle body.

The kind of gaskets used on door handles are a molded thermoplastic that is UV tolerant. Gasket material for sealing auto engine, transmissions, etc. is not make of the type of material that will withstand exposure to direct sunlight for long periods, and will probably deteriorate pretty quickly if used on door handles.

I don’t recommend using any of the supposed “R12 substitute/equivalent” refrigerants in vehicles. Given that the AC system in the MJ was sized to deal with the internal volume of the XJ, the system has MORE than enough cooling capacity to deal with any performance reduction seen by switching from R12 to R134a. If an MJ owner is considering rebuilding his AC system, a proper conversion to R134a is straightforward and will yield excellent results.

New gaskets can be fabricated from 1/16” thick ABS sheet plastic that is available on Amazon.

The 4.0 engine has what is called a "controlled crankcase ventilation system". That means that the rear hose is sized such that an engine in "as designed" condition will suck normal amounts of crankcase vapors through that rear hose and burn them with the combustion air being drawn into the intake manifold. When a 4.0 engine becomes substantially worn, this vent hose is not large enough to deal with the larger-than-normal amount of blow-by that the cylinders leak into the crankcase past the piston rings. Once this condition exists, the crankcase now has more pressure in it than the rear vent hose can scavenge from the bottom end of the engine, and the excess vapors now seek another way out. That way out is the front hose on the valve cover, which is normally providing INLET AIR to the crankcase. The end result is oil vapors in the air filter and air box. One can increase the size of the rear crankcase vent hose, but that also upsets the airflow mass being measured by the MAP and Throttle Position Sensor, and will result in a leaner mixture. A little bit of extra crankcase vapors being sucked in by a larger vent hose is not seriously harmful, but a large amount will cause long-term engine damage. (Using a PCV like "Pizzaman09" suggested helps limit the amount of crankcase gases being drawn into the manifold to some degree.) The real fix, of course, is to fix the blow-by on the engine by reboring the engine for oversized pistons/rings.

That cover is used mostly to keep people from kicking the latticework grate on the bottom of the heater box where recirculating air enters. The grate is plastic, and can easily be broken not someone with big feet. It is not essential to operation of anything on the vehicle.

If you search on Amazon, you can find multiple choices there. If you don’t mind paying a bit more, Crutchfield offers a searchable database of their offerings, plus an installation kit that will make installation and hookup much faster, if you lack a wiring diagram and a soldering iron.

JVC and Pioneer both make single DIN radios that fit MJ/XJ dashboards. They offer models that are Bluetooth/USB, and some also have CD capabilities as well.

The purpose of the foam is to seal the recirculation door against the heater housing. It also cushions the door as it moves to that position against the lattice work. You can purchase sheets of “closed cell neoprene foam” of 1/8” thickness on Amazon. It can be attached to that recirculation mode door with spray adhesive. Of course, to do this, you must remove the heater box to remove the door for this repair.

I believe this is correct. I seem to recollect that the trans control subsystem changed when they went to OBD2, and was further refined in the last couple of years of XJ’s.

I am retired, and I know about cash flow. I had a machine shop redo the short block on my MJ, which had budgeted for. However, that interrupted over the past 12 months by unexpected heart surgery due an infected heart valve.😳

Current factory Mopar branded oil drain plugs have a polymer washer that is molded on to the flange head of the drain plug bolt. Dorman makes an equivalent, and is available from Oreilly auto parts. Drain Plug

Fusible links were popular in some brands of domestic vehicles up into the early 1970’s. Apparently AMC did it longer than others, probably due to budget constraints. If I was redoing any power wiring in an older MJ/XJ, I would ditch the fusible links and put in a small fuse panel like show earlier in this thread. It’s easier to diagnose issues and control power distribution with such an improvement, and the cost would relatively low.

its possible that those loose/damaged spindle threads have damaged the existing bearings in ways you cannot see completely. The cost of wheel bearings listed on Rock Auto is so cheap I would just plunk the cash down for all new bearings and seals and remove any doubts about those elements from the equation on any source of the noise.

Yeah, the mounting scheme for the Saginaw steering box in the MJ and XJ is not the best. Aside from the fact they only use three bolts (instead of four found in other Saginaw boxes), they rely on some formed internal sheet metal spacers to keep the two "walls" of the frame from collapsing towards each other when the mounting bolts are tightened. Further complicating the flimsiness of the mounting is that the walls of the frame are not that thick, so getting rambunctious with the wrench when tightening the steering box mounting, one can potentially collapse the frame in the steering box area. The aftermarket steering box spacers help to reinforce this part of the frame, as does the use of large HARDENED washers under the heads of the steering box bolts. (Using longer steerring box mounting bolts allows the use of such washers.) And how do I know this? Because my MJ was wandering on the road, and I found that my frame was cracked around the steering box bolt holes, causing the box to move when the steering wheel was turned. (A previous owner had put some monster swamper tires on the vehicle, and it overstressed the box mounting.) To fix this, I ended up welding in more robust spacers and some gusset plates to fix the cracked frame walls. Since I have performed that repair/upgrade, my steering box has been noise free, solid, and steering is more precise (at least more precise for a solid axle pickup truck with recirculating ball steering.)

The following observation is almost worthy of being posted as a “sticky” on this forum: All of our MJ’s are really pretty old vehicles nowadays. That means any rubber components in the suspension system are really dried out and probably cracked from age and/or heat if they are still original. That means that anytime there are noises in the suspension, or irregular steering behavior, a detailed inspection of parts is warranted. Even more important is that, if anything in the suspension/steering is suspect or “slightly worn”, it probably would be wise to replace that part general principles. BTW, this applies to engine and transmission mounts as well. Those OEM mounts were not the most robust to begin with, and thus can benefit from replacement even if they “seem” OK.