I don't know, if this is the "right" way to do it. It is just the way I did it. I will post more details and photos later, if there is an interest.
I have a complete set of Technical Manuals for the Mule in paper form – and some manuals on my computer. The paper copies are much easier to use during the operation, as it is faster to find information by flipping the pages and you don’t get grease all over your computer keyboard.
The following list of manuals should be considered the bare minimum for this operation. I did discover that there are some inaccuracies between what was in front of me at the time and what the book said – most likely due to the TM date.
TM 9-2320-246-20, Organizational Maintenance (Engine removal)
TM 9-2320-246-20P, Organizational Maintenance Parts (Parts identification)
TM 5-2805-213-14, Operator/Direct/General Support Maintenance for the AO42 Military Standard Engine (Everything about the engine)
TM 5-2805-213-24P, Organizational / Direct / General Support Parts for the AO42 Military Standard Engine (Parts identification)
I am sure I also used this list of manuals – just not as much as the above list. If you don’t have a complete set of the manuals for your Mule, you should get them – you know, just so you have them.
LO 9-2320-246-12, Lubrication Order
TM 9-2320-246-10, Operator’s Manual
TM 9-2320-246-34, Direct / General Support Maintenance
TM 9-2320-246-34P, Direct / General Support Parts (Parts identification)
Common tools needed – screwdrivers, pliers, set of 1/4” to 7/8” combination wrenches, 3/8” socket set, 1/2” ratchet and socket for crankshaft pulley (15/16” socket) and spark plugs (7/8” x 2 3/8” depth) – (This socket might be hard to locate. None of the five suppliers in town had one.), come-a-long hoist, 3/8” eye bolt (There is a threaded hole in the top of the block. This eye bolt will thread into the hole and allow you to hook the come-a-long to the engine.), clutch / pressure plate alignment tool (Small diameter of .620” for a length of .765”, next diameter of .750” for a length of 1.540”, then enough length for a “hand hold”. I made this tool myself. If you need to use it, please let me know, and I will get it to you.).
Use a two prong gear puller to remove crankshaft pulley. Be careful! This is a cast iron pulley and easy to break. Luckily mine was “pre-broken”, so all I had to do was find another one. It had been brazed together at the spokes, but the run out was severe enough to require replacement. I fabricated a puller to remove flywheel, as the smaller two prong puller was not long enough. This was really nothing more than a 1/2” thick by approximately 2” wide by approximately 24” long piece of flat steel. Drill a hole in each end to match the appropriate threaded holes in the flywheel and another hole in the center. Use a bolt with a nut on the bottom side and tighten the bolt to remove the flywheel. A 1/2” impact wrench was needed to remove the crank pulley and flywheel. I used my propane torch to apply heat to some of the more stubborn fasteners. They came right off after that. I thought I needed a torque wrench, but did not.
I dropped the engine down from Mule. There is no need to lift the Mule to remove the engine. No need for jack stands. I had some years ago, but can no longer locate them. I bought a set of four – and they are still brand spanking new. I suppose I will try and keep track of them, but I really don’t like crawling around under vehicles much anymore.
I did discover that one “leg” of the upper air cleaner housing was broken. Luckily, the part was still bolted to the bottom of the bed and after short a trip to the machine shop, the part was welded together again. I only broke one bolt during the entire operation. A bolt in the timing gear cover twisted off, as I was removing the cover. Since this was in the original Mule engine, this was not a problem. The 3/8” socket set lessens the probability of twisting off bolts, but it is much easier to allow a bolt to soak and perhaps use some heat then it is to remove a broken bolt from aluminum.
I used two engine stands. The Generator Set engine without a bell housing is placed on one stand to disassemble. I used the second stand to disassemble the original Mule engine. Once the original Mule engine is disassembled, remove it from stand. Remove the bell housing from original Mule engine and install it on the Generator Set engine. Build the Generator Set engine – with the installed bell housing – on the stand. Sure, you can do it with only one stand. I am just describing the way I did it – plus the jack stands, torque wrench, and engine stand makes a nice package of stuff I probably won’t ever use again. I did return the second engine stand from the guy I borrowed it from.
Make a list and take photos of each part removed from original Mule engine. Place parts with hardware in order. Reinstall in reverse order. Engine shrouds are confusing. Remember to use your layout order and disassembly list.
As gaskets are identified from gasket set (Use section IV of TM 5-2805-213-24P), place them with the parts to be reinstalled. NSN for gasket set is – 2805-00-984-4765, Kit, Engine Gasket. You will have many gaskets in the set you will not use. Don’t throw them out. Spare parts are good. The oil pan spacer and oil pan gaskets are not included in the gasket set and must be fabricated. I used common “gasket material” for the spacer and a “rubber/cork” gasket material for oil pan. You will also need to make gaskets for carburetor and air intake manifolds from the same “gasket material”. I constructed gaskets for the exhaust gas bypass tubes to air intake manifold from copper pipe. I used some 2” copper pipe that I had laying around. I have hot water heat in my house and have had to make some changes from time-to-time. Anyway, I used about 4 inches of the pipe. Cut it down one side. Anneal it with your torch (hot torch then cold water) to soften it. Flatten it out. Cut some parts out that look like gaskets. Yes, I know sounds like a pretty neat trick. Sorry I did not get any photos. This was an idea from my Brother-in-Law, so if it doesn’t work, he gets the blame. Of course, if it does work – well, he doesn’t read this forum. The Generator Set engine has a “new” seal in timing gear cover. Remove it and reuse it in original Mule engine timing cover. Use TFE (Teflon) paste pipe thread compound on block oil line adapter fittings and plugs. Do not over tighten any fittings! Remember Teflon acts as a lubricant, so things can get tight pretty quick.
I used the larger governor oil line from the Generator Set engine. I could not remove the fitting from original Mule engine for the smaller line. It works fine and more is better, right?
I used the spin-on oil filter bracket from Generator Set engine and saved the original parts of the canister oil filter. The spin-on filter will be a Fram PH8A filter. I added 2 3/8 quarts SAE 30w oil and 1/8 quart (4 ounces) of Marvel Mystery Oil.
I was able to find the following parts - Fan belt (NAPA 3VX350), Fuel filters – (NAPA 3034), and Clutch Throw-out bearing (NAPA N1054) at my local auto parts store. I used the new style fuel pump already installed on the Generator Set engine and kept my original “flat top” style (which worked, when I removed it) for spare parts. The Generator Set engine has new connector hoses for your intake manifold to intake manifold elbow assemblies. Don’t throw them out. Spare parts are good.
Engine paint color was Krylon Camouflage Ultra Flat #4293 Olive (SKU 2450404293) from Ace Hardware. This is not the correct color, but it was as close as I could get here in town. If the whole thing doesn't work, I will repaint it, when I have to pull it, again.
I removed the data plate from the top shroud in order to repaint the shroud. The data plate is fastened with “pop rivets”, which are easily removed and then replaced after painting. I thought this was easier than masking the plate. All parts were wire brushed before painting. I fabricated a governor cover, because mine was missing and they are rather difficult to locate.
Once your new Mule engine is running, you will have a rather large pile of Generator Set engine parts. It seems to me that some of these parts might be usable to someone, but not your Mule. Well, there might be a couple of parts yet to be installed on the Mule. My Brother-in-Law has another idea – not sure how it will work – or even if it will ever be anything other than an idea. It sounds like a cool idea. Think charging system.
