AZJeff

Given that the AMC-era connectors were such a piss-power excuse for completing electrical circuits, I would go out of my way to replace that junk with something better (unless you are attempting a "pure" restoration of your MJ/XJ.) I cannot beleive the connectors that were chosen, even in the period when the MJ/XJ was designed (the mid-1980's). There were SO MANY better connectors that had been in use for MANY years by other auto makers at that point. It's almost like the AMC electrical design team tried to surpass British Leyland in choosing the most worthless interconnect systems for the elecrtrical wiring.

Others have talked about the expansion process, but I will address your other questions: You will need to acquire an evaporator and a compressor intended for use with R134a, if that is the refrigerant you have chosen. R134a is not as efficient as the old R12, and so components were resized when the switch over was made. Likewise, your receiver/drier will need to be R134a sized. You cannnot use hydraulic hoses for refrigerant lines. The refrigerant molecules are MUCH smaller than oil molecules, and will litterally escape through hoses that don't have the proper barrier layer in them as would a true refrigerant hose. There are shops out there that will make custom refrigerant hoses, you will just need to search for one.

That's a good alternative, if you actually have crimp tools. If you don't (like me), I just solder/heatshrink the connector pigtails into the wiring. The old Molex "Econo-Latch" connector is PERFECT for this role for interior lighting connectors, as it's cheap and simple, as well as being polarized. Too bad it requires a lugging tool to attach the contacts to the wires correctly.

As an "old school" ME (FEA did not come along until I was in management, so I only know the theory, and have never actually used it), here is my take: If you have interior hat sections that are reusable, by all means, reuse them (with appropriate plug welds as shown in photos elsewhere in this thread.) If your interior hat sections are trashed (or missing) and you want to achieve OEM stiffness (or better), plating the sides of the uniframe will do more to improve the moment of inertia of the "frame" of an MJ that those silly hat sections would ever do. And yes, we can be friend, both profession career wise and otherwise. Don't you LOVE it when engineers start arguing the best way to do something?

Unless you are trying to restore your MJ to factory condition, ditch those weird proprietary connectors and go buy something on Amazon. Given that the application is an interior electrical connector, the need for environmental sealing (waterproofing) is non-existent, so a bunch of stuff is out there for cheap. Here is a good example of something you can use: https://www.amazon.com/MUYI-Waterproof-Connector-1-5mm-Terminal/dp/B01A6LTK44/ref=psdc_15729341_t1_B01F54PFLE

While I agree that (as a retired engineer), the 'designed it that way for a reason' is a good logic, keep in mind that the XJ did NOT have this added "hat section" welded to the top of the floor pan. They only relied on just the lower "hat section" that forms the uniframe with the floor pan for that vehicle. Putting on my mechanical engineer hat here, I suspect the issue has to do with the fact that the MJ lacks a roof that extends all the way to the rear of the vehicle, and the transition point from the cab to the "pickup truck frame" section is a critical point in the chassis stiffness, and adding this hat section added some stiffness. HOWEVER.......The size of those hat sections, and thus the amounted of added stiffness they provide, is NOT significant (compared to the lower uniframe hat sections), so I do not know if their loss would be monumental. One can duplicate the added stiffness of those hat sections in a variety of other ways, not the least of which is plating the sides of the uniframe on the bottom of the floor pan. My point is that the loss of the upper hat sections is not SUPER critical, but if you feel you need to add stiffness, there are other ways to do that that might actually be BETTER (but were not done by Jeep for economic reasons.)

Now that I have heard the ZJ is superior to the original MJ/XJ box, this interests me too. I would be interested to hear more of the sucess of those who dropped in a ZJ box in their machine.

I learned my lesson when I went through multiple reman’d steering boxes from AutoZone for my old F150. They tended to be short lived. I got lots of practice changing boxes in that truck. When my MJ needed a box (the PO had adjusted the box in a manner that trashed the box), I bought a reman’d unit from AC Delco via Rock Auto. I figured that Delco ought to know how to reman a Saginaw box, since they are/were both divisions of General Motors. Thus far, I have been happy with it.

The angle between the sway bar link and the end of the sway bar is supposed to be pretty close to 90 degrees when the vehicle is sitting at normal ride height. On a lifted MJ/XJ, you might have trouble getting there without moving the sway bar brackets as well as getting longer links when the lift gets over about 3 inches. My MJ with a 3.5" lift has longer links AND relocating brackets for the sway bar mounts that push the sway bar mount down and forward to restore that 90 degree angle as shown in the picture.

That's a nice looking truck!!

Can you jack it up so all the wheels can turn by hand, and then have some helpers turn those while you fiddle with the linkage?

I am glad you got it out., and I will admit, I find that plug quite amazing. I have seen allen plugs, and hex head plugs, but never an eight-pointed plug. (Notice carefully it's NOT a "Torx" shape, which has curved tips of the "points" of the star shape. Maybe one of our "seasoned" Jeepers can comment if this was ever a common type of plug.

I have been down this road with SEVERAL vehicles, so here is my $0.02: 1. Eagle is correct in that a thermostat controls the MINIMUM temperature the engine will see when warmed up, NOT the maximum temperature. 2. The maximum temperature is governed by radiator size and/or air flow rate across the rad. That is, of course, a function of the size/number of fans being used. 3. If you want the fan to come on at a lower temperature, you either need to select a different temperature sensor to fit the Renix sized port. Otherwise, putting a temperature sensor in-line on the UPPER radiator hose is the best way to control when an electric fan turns on. WHy the upper hose? Because that is the temperature of the HOTTEST water going to the radiator, and you are trying to control the HOTTEST coolant temperature.

I have never seen an NP231 with a Torx headed plug. It's a Allen type (hex socket) that may be bunged up by previous "repairs". Start by cleaning the crud and corrosion from in the hex hole, and use a pick or the like to clean the corners of the hex. Then you can do a trial and error search for the best SAE or metric allen socket to fit it.

The best method is the ball joint press. the other methods of drilling or burning out the rubber and then hammering out the remaining steel sleeve is far more tedious. Autozone will loan a ball joint press for “free”

Thanks for the tip. Looking at reviews of the Remflex part on Amazon, other Jeepers are saying the same thing about it being the best. They pricey, but "buy once, cry once"

After my "0331" head calamity, I have now found that one of the OEM cast iron manifolds won't seat properly on the new cylinder head near the #6 exhaust port, and thus I have an exhaust leak until the engine REALLY warms up (like about one hour of running or more.) So.....I bought new manifolds, but I am unsure what type of gasket to use. The OEM type gasket is a composite of embossed stainless steel and some sort of fiber material, with the stainless steel around the exhaust ports, and fiber around the intake ports. Another gasket I have laying around from extras when I replaced the head is a Fel-Pro one that is made completely of some sort of fiber type material. So....based on experience, which type is more durable/reliable? I know my new cylinder head from Clearwater is flat/true in the manifold area, and I assume the new manifolds are equally flat, so I am not trying to overcome some warpage. Inputs/suggestions welcome.....

For rear (and front) axles, Jeep has always said that 80w90 is the "normal" lubricant, and if towing (or other severe use conditions), 75w140 is recommended. Here in AZ, where temperatures can get danged hot, I use 75w140 all the time in both my front and rear diffs.

Make sure you get tubing that fits tightly over the hard tubing. Lots of the stuff used for vacuum lines at the auto parts store have an ID that is too big. I found this out when replumbing the vacuum on my 1991 F-150 truck.

They have special paint that can be used on plastic trim. I STRONGLY recommend you use that. Using "regular" spray paint might cause some weird stuff to happen to your plastic, and ruin it. The stuff I use is from Colorbond, and can be found on Amazon.

A LOT of the reason there is a mix of fastener types between metric and SAE on older Jeeps has to do with the history of the pieces used in them. For example, the axles and engines date back to the AMC period, specifically into the 1960's. In the 1960's, ALL domestic vehicles used SAE fasteners. As time went on, the industry began transfer to using metric fasteners, particularly in the late 1980's and beyond. BUT.....if they were using a part or subsystem that was a legacy item from the earlier models with SAE threaded fasteners, there was no real economic reason to retool the part to switch to metric fasteners. That legacy stuff stayed SAE, and only newly design parts and subsystems got metric stuff. Jeep wasn't the only one who did this. My old 1991 F150 was SAE all over the engine and rear axle, but metric in the transmission and PART of the body. And one other thing: AMC bought LOTS of parts from other auto makers. Whatever THAT maker used for a given part might be SAE or metric, depending on a bunch of factors. The AW-4 transmission is a good example: it was designed/manufactured in Japan, where metric fasteners have been commonplace for along time. That is why the threads on all AW-4 fastners are metric. (It's also why the one stater bolt holding on a starter for a 4.0 married to an AW-4 is SAE and one is metric. The one threaded into the trans is metric. The one threaded into the starter (an older US design) is SAE.) It can be fun to figure this stuff out, so the only solution is a full set of sockets and wrenches in both SAE and metric.

I found out my 2014JK has a fuel guage sender that is virtually identical to the one in my wife's KJ, and very similar to the one in the Dakota fuel pump/sender assembly I use in my MJ. I wonder if the real reason they work better now is that the consistency of the production of the senders and guages is better now due to automated calibration methods. I know when I worked in the electronics industry, we had shifted from manually "trimming" resistor networks that were embedded on ceramic substrates to using lasers to do so, as they were FAR more precise that someone with the industrial equivalent of a Dremel tool and a diamond cutter.

See those two sort of bronze colored hex head plugs on the back case half at the top of the photo above? Those are the drain and fill plugs. I would be wise to remove both and clean their threads before refilling.

Perhaps. The one in my wife’s 2004 KJ is still a wiper across a thick film resistor trace, so that’s “old school” I will investigate what sort of sender my 2014JK uses....

Older vehicles have notoriously inaccurate and inconsistent fuel gauges. I have seen cars that read “1/8” and were fully empty. I have also owned cars that had 4 gallons left from a 20 gallon tank when it reached “E” However, the one in my Wife’s KJ is pretty good, and the one in my JK is almost exact. I think that have improved calibration procedures in the past 20 years.