AZJeff

It sounds fairly normal to me, but it's a bit hard to tell for sure, because I hear several different rhythmic noises in your two video clips. You can help pinpoint the source of the noise by using a mechanics stethoscopic and probing around various parts of the engine. If you lack the stethoscope, then a section of wooden dowel rod, or a long screwdriver, can substitute.; The 4.0 is not a quiet engine, but most of it's sounds should be steady and rhythmic. Trying to make it as quiet as some newer engines is pretty much impossible.

THIS, TIMES ONE MILLION. The BEST bit of advice given above is to get a REAL service manual for your model year, if you do not have one already. Chasing wiring issues without the manual and it's critical wiring diagrams is like trying to drive in a strange place without a road map (pre-GPS days). If you are not familiar with, and own, a multimeter to measure continuity and voltage, go on line and learn how to use one, and then go buy something that does the basic measurements. Automotive wiring of the era of the MJ does not require a fancy multimeter. Even the old "moving needle" type that Radio Shack used to sell will do the job, so the dollar investment isn't large.

The "leading" shoe of a drum brake system (the one towards the front of the vehicle) is ALWAYS smaller than the "trailing" shoe. What you found is perfectly normal. When I studied brake systems in college as part of my mechanical engr. degree, we were taught that drums brakes are designed to be "self energizing," meaning that once the shoe contacts the drum, the frictional forces tend to actual encourage the shoe to pull tightly agains the drum surface, and maintain the frictional bond. If and when you install new shoes, make sure that the shoe with the smaller/shorter arc of friction material in located on the FRONT side of the assembly. BTW, based on the one photo you provided, your brake hardware (springs, brackets, etc.) look pretty decent. A new set of shoes, and a properly turned (or replaced) brake drum will restore your service brakes to original condition. If your parking brake is non functional, you will need to replace the cables, etc. regardless of whether you restore your drum brake system or replace it with the disc setup off an Liberty or similar.

That's true, Pete. However, he still needs to get all the hardware off the end of the axle to do any rebuild or upgrade of the rear brakes.

That is very similar to the "Ziebart" undercoating that my dad put on his cars back in the 1960's and 1970's when I lived in Illinois. It works pretty well INSIDE a hollow, boxed compartment. It tends to be abraided off an external surface that gets water, salt, sand, dirt, etc. thrown up on it. Because of that, it needs to be reapplied every couple of years.

The only thing that holds the top part of the shoe to the backing plate is going to be a sort of "diamond shaped" retaining plate that is slipped over the top of the upper shoe anchor stud on the backing plate. That retaining plate is, in turn, captured on the anchor stud by the upper shoe return springs. There is no way to get those upper return springs off with the drum in place. Here is my suggestion: There is a shoe retaining stud/spring assembly that holds the shoe to the backing plate. The head end of this stud pokes out through a hole in the backing plate. If you can cut/grind or otherwise break the head of the stud off the back side of the backing plate, then the shoe (and the drum) can move further out (with prying) and then maybe you can start taking the adjuster assembly out through the gap between the bottom of the drum and the backing plate. Once the adjuster is out, the shoes can collapse inward further, and make getting the drum off easier.

I second this, after dealing with rust on many vehicles over the years. The hollow compartments in the chassis of the MJ (such as the rocker panels) have dust/road dirt seep in slowly over time (they are not airtight). Then, moisture from rain (and salt water in areas that use salt on the roads) also seeps in, and the dust absorbs this moisture, creating "mud" that holds the water/salt against the steel. That's the perfect way to get corrosion going. The secret is to: (1) make sure all hollow compartments are free to drain of dust/dirt/water as much as possible. The designers do provide SOME drain holes, but the often are too small to do a good job. (2) flush the boxed compartments as best as you can with fresh clean water to drive out the dust/dirt/salt, etc. (3) consider using some sort of protective coating in the hollow boxed compartments if you live in an area where moisture/salt is present during a large portion of the seasons.

Is that with or without a gasket?

My AW-4 transmission pan started leaking recently, so I put on a new Fel-Pro gasket and used black Permatex RTV gasket sealer on both sides of the gasket. I torqued the gasket bolts using my calibrated "wrist tight" method that I have used for the past 40+ years of working on vehicles. I am confident I did not overtorque them, and the gasket does not look distorted around the bolt holes. None the less.....the leak is still present, but it is lessened. My questions are: 1. can the pan be installed without a gasket, and just use the appropriate gasket making compound directly on the pan flange, like what is done on differential covers nowadays? 2. if a gasket is needed who makes the best gasket for this application? (I alway have felt that Fel-Pro was good to go for most gaskets.)

That is true. At one time, (before the advent of very consistent machine tools) it was not unheard of for an engine to have oversized cylinder bores as well as undersized bearings straight from the factory. During that time, fully assembled engine blocks would be stamped with a series of coded letters/numbers to indicate what features are over/undersized, and the factory would supply dealers with the way to decode those added markings. It's pretty rare to see that today. I was surprised when my 2000XJ engine in my MJ came with 0.001 undersized mains, but standard sized rod bearings as new.

You are correct about there being 0.001 undersized rod bearings being available from Rock Auto, but only Sealed Power brand. It’s odd the local Jeep dealer here did not list that part, but only the mains…

To the best of my knowledge, the factory on used 0.001 undersized bearings on the mains only. The rods were always standard. At least that is what I found when searching for new bearing shells for my engine. The dealer listed a 0.001 undersize for mains, but nothing for rods.

Clevite is my choice from Rock Auto. Rod bearings only come in sizes where the journals are standard size, or 10, 20, or 30 thousandths undersized. I cannot imagine a journal wearing 0.010” undersized evenly by itself. The only way it can get that way (and be even) is by being machined undersized. FWIW….

Trivia bit: most of AMC's radiators were made by Blackstone Corp. in Jamestown, NY. The company founder sold the business to some Swedish outfit in 1984. They still manufacture radiators for large trucks, and, since they are Swedish, they have a factory over in Europe that supplies radiators to Volvo.

Yeah, but what is it when idling in traffic this afternoon on the way home, when it's 107*?

Factory spec. for a 4.0 is 13psi minimum at hot idle, and 37psi minimum above 1600 rpm. (This assumes using the recommended 10w30 or 10w40 oil.) Here in AZ, in the summer, the oil pressure on the 4.0's I have owned isn't really very high when the engine is REAL hot, generally being about 40 psi at road speeds. (Underhood and pavement temperatures in Phoenix are something everyone should experience to see how oil pressure drops down as the engine heats.

Putting recycling codes on polymer parts wasn't a common practice when the MJ's were in production, so it's not too surprising to see forum members reporting not finding such identifiers on interior parts. Based on my years of experience with resins when I earned a living as a mechanical engineer, I think that most of the pieces of the interior of an MJ are ABS. (Newer vehicles use ABS/polycarbonate blends for these applications, but the MJ predates that use.) ABS can be repaired by solvent welding and also with some of the filler resins out there pretty sucessfully. The kick panels and similar stuff are probably polypropylene, which is more flexible and has an almost "waxy" feel to it. Polyprop is much trickier to get welding to work successfully.

For checking steering linkages, I like to get a helper to sit behind the steering wheel and move the wheel back and forth just enough to get the front road wheels to begin turning right or left SLIGHTLY. (Do it with the engine off.) While he/she is wiggling the wheel, lay under the vehicle an place your hand around each steering linkage joint. You are attempting to feel for relative motion between the two parts of each joint. There should be none. If there is, that joint is bad. Next, jack up each front wheel and place a large pry bar under the tire. Lever up on the pry bar, and look for any motion between the wheel assembly and the axle housing where they are connected by the ball joints. Any motion means one of both ball joints are bad. Control arms are best examined with a strong flashlight. You are looking to see of the outer sleeve of the control arm bushing is still centered on the inner pivot/attaching bolt. Looks for cracks in the rubber that fills the space between the outer sleeve and the pivot bolt. if there are significant cracks, or if the bolt is eccentric to the outer bushing sleeve, the bushing needs replacing.

Let me ask a question--have you actually seen symptoms of overheating (radiator boil-off)? Have you confirmed that tne temperature is as indicated on the instrument cluster? I ask this because in my MJ (which has a late model XJ dash), the gauge reads about 10* higher than the actual temperature of the coolant. I use an infra-red laser thermometer aimed at the thermostat housing to verify what my guage says, and perhaps your guage (or sender) are not giving you real temperature readings.

It's possible that your flexible rubber brake line between the chassis and the rear axle has collapsed internally and is blocking fluid flow. I would start by disconnecting the chassis end of that line and see if fluid flows. If it does, then reconnect and check the axle end of the line in the same manner. In all honesty, with vehicles as hold as ours, unless the flexible brake hoses are new or appear to be recent, replacing them is a wise safety precaution.

I think that "check valve" is an overpressure safety valve. I am not familiar with all the fittings on the older MJ's, but that is what they looked like on my old Ford F150. I am certain that others can confirm if that is what this part is on your MJ.

In general, I am not a big fan of closed cooling systems, (although the wife's KJ has one, and it seems to work fine.) If I was replacing the coolant tank more than once in a few years, I would be HIGHLY motivated to convert to an open system, as they don't seem to be as vulnerable to crappy aftermarket parts as do the closed systems.

Was there any reason you didn't lay into it with a propane torch? If the expansion valve was aready off the vehicle, the amount of refrigerant was pretty much zero, so heat would not generate noxious gases, but it sure would loosen that rust.

Cruiser, where do you dig up this stuff? I am impressed. And for the OP, aside from the fastener size difference on the four "corners" of the pan, I just put the ones with the stud heads on them whereever I see a bracket that is supposed to be anchored to the stud side. That's usually the trans. cooling lines, and the O2 sensor wires on the model years where that is applicable.

When temperature drops dramatically when the vehicle starts to move, it's because air is now flowing over the radiator at a much higher rate than when the vehicle was stationary. The cooling fan(s) are supposed to cause air to flow when the vehicle is stationary. If they do NOT, then coolant temperature will rise dramatically. All MJ's have one mechanical cooling fan with a viscous clutch. Most MJ's also have an electric fan that acts as a booster, and is present if the vehicle has AC or a heavy duty cooling system. We will ignore this for purposes of this discussion. When this mehcanical clutch/fan (and associated fan shroud) are properly functioning, the fan should be able to keep the engine within normal operating range when the engine is idling and stationary. It sounds like your clutch is not engaging properly, and allowing the fan to "slip" on it's shaft even when the temperature would call for the clutch to "lock up" and allow the fan to spin at high speed. In addition, when an MJ is running down the road at a speed of 45mph or more, the fan no longer becomes a factor in keeping the engine cool. There is enough air entering the radiator through the grille to keep the temperature at the normal level, whcih should be about 210*, give or take 5-10 degrees. If your temperature is dropping to much lower than 210, it means your thermostat is opening WAY too far, and allowing too much coolant flow through the radiator, and thus OVERCOOLING the engine. A new, high quality/brand name thermostat should fix this. Be sure to get a thermostat set for 195*, and NOT one that is set to open at lower values like 160* or 180*