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The M38A1 Hybrid/Project Step by Step Chassis up rebuild |
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Engine, Gearbox and Transfer Case
Terms Hood - bonnet Fender - mudguard Petrol - fuel Indicators - flashers Dials - instruments Windscreen - windshield Propshaft - driveshaft Chain hoist - chain lift Bakkie - pickup truck Tyres - tires Rims - wheels |
The obvious first step is to strip the Jeep - look in the Tech Tips section for preparation of your workshop and what tools you need.
I started with the front section, removing the bonnet by opening it about halfway until the pins can slide out of the hinges. Next is the front grille - first remove the lights and indicators, labeling the wires. Remove the bolts from the sides and a single bolt from the bottom (if you have the pre-1953 M38A1, it will have a hinge at the bottom). The fenders can be removed by firstly making sure all the ground wires and whatever else is attached to the fender's insides are detached. Then remove the bolts fastening it to the body tub.
At this stage, I removed the insides of the Jeep - seats, fuel tank, etc. At the same time, I removed the electrical harness - a good idea here is to have a roll of masking tape and a pen handy. When you remove a wire, label it - and I mean every single wire that you remove. The wiring harness threads through the chassis to reach the back lights - note where it goes and remove it in one piece. It's a bit tricky to get the whole harness through the hole in the firewall, but it can be done. You can remove the battery clamps section and other big stuff to make this easier. Once the wiring is removed from the dashboard, you will have half of it undone already (to have reached the wires). Remove the rest of the dashboard - you can remove the dials, etc, as you will be cleaning them, maybe even having the chrome redone, right? The dashboard is basically just a piece of flat metal, so if yours is too badly damaged, you can cut one from a piece of sheet metal. Just use the old one as a template. Some people chrome theirs, or even make dashboards from wood. The steering wheel has to be removed for the steering column to pass through the firewall. Undo the steering mechanism on the front part of the chassis, and remove the whole steering in one piece. Later you might want to fit power steering - more about that later. The windscreen frame can be removed by tilting it about halfway till the pin (flattened on one side) lines up with the slotted hinge - then lifting that side out. The other side then slides out. If you're lucky, you will have windows in there, in my case not. Some people prefer to use the original split inner frame and fit two windows on this frame. Advantage: your inner frame can tilt up. Question: whatever for? If you're not doing an original restoration, just take the split inner frame out, and fit a one-piece window (much later on...). Next is the removal of the body tub. Make sure everything is removed from the body tub first - here we're talking about back lights, fuel tanks, roll bars, seats, in fact, everything that can be removed (it's a chassis-up re-build, right?). The body tub is bolted onto the chassis by approximately (depending on how original it is) 6 - 12 bolts. I wouldn't know exactly, as mine had non-original spacers. A good idea would be to get a buddy (one is enough - two if you need one to fetch the cooler box with the beers) to help you lift the body tub off. It's not heavy - two people can carry it easily. Here's a tip - make a place to put it before you lift it - no need to feel like a fool standing around with a body tub in your hands and no place to put it. Are you starting to see how simple these things are? Two fenders, a grill and a hood, a body tub and a chassis - that's all it takes to make it look like a Jeep. You can remove the radiator and the radiator cowl (or shroud) and the hoses - remember that the thing contains water, and lots of it. If you don't want the water on your garage floor, then let it empty into one of those handy 20 liter drums you keep around. You know, the ones that you buy bulk cooking oil in. What do you mean you don't buy 20 liters of cooking oil at a time? Now comes the part where you need a chain hoist. Fortunately my garage roof beams were strong enough to support the weight of the engine with the gearbox attached. Make very, very, very sure before you lift stuff with the chain hoist that whatever it's attached to can support it. Nothing worse than an engine falling on you... The engine is attached at the bottom at two places...but wait! First make sure fuel lines, the wire to the coil (normally sitting on the firewall), the brake booster lines, power steering lines (if you have), generally everything connecting the engine with what will remain behind, needs to be undone. Engine bolts removed, propshaft u-bolts removed - only then, and making sure nothing is snagging, you can slowly lift the engine. The slowness of this operation ensures a) you're testing whether your roof beams can support the weight, and b) nothing is hooking or snagging in the lifting process. OK - rewind a few steps (you are reading this through before doing it, right?) and make sure that when the engine is lifted high enough, the chassis has somewhere to be rolled out of the way. You now have a problem - when you lower the engine, it's in the place where you want to work on your chassis, right? You sort that out - I used a double garage, and all of it for my workshop. You know you're dedicated to your hobby when you go and buy a smallholding with a workshop on it to build your project Jeeps, but that's another story altogether. Depending on how thorough you want to be, the chassis can be removed from the axles, and the leaf springs from the axles. If it is a pre-1957, the shackles will be the screw in ones. If it is a proper M38A1, then the shackles on the front springs will be in the front - which leaves us with another question: If mine is indeed a M38A1, then why are the shackles at the back? Possible answer here is that the staff cars had them at the back for a smoother ride. I don't buy it... I took my leaf springs of, as I wanted to re-spray them. You can remove the propshafts from the diffs for easier handling, but leave the wheels on for now. It's much easier to wheel the axles around to work on them. That's about it for the stripping - I'll talk about each part's disassembling at the same time as putting it back together - it's the same, just in reverse!
Once the chassis has been stripped bare (and I mean bare - no bump stops, no nothing), you can inspect the chassis for rust, damage, etc. I was fortunate - my chassis was in very good condition, apart from a hideous bull bar that had been welded onto the chassis. I used an angle grinder to remove the bull bar, but the damage on the front bumper was a bit too much too repair and still have it look good. I decided to replace it with a 50x100 rectangular metal tube. The dimensions are exactly the same - I just had to cut two holes for the front part of the chassis to bolt into. I cut the ends at the same angle as the original bumper. I will have a bull bar made to my specifications later to fit onto and in front of the bumper. Since the Jeep would be painted black, I thought I'd paint the chassis a matt black primer. The chassis had to be sanded down with a 400 grit wet paper, then wiped down. I used my compressor and an air hose to remove the last bits of dust, etc. Before you spray, the chassis must be clean of oil and dust. I used a matt black etching primer. This was not strictly necessary, as most of the original red oxide primer was still left, but I felt that the parts that was bare metal needed it, so I did the whole thing. It's a relatively quick job to spray the chassis - took me about twenty minutes. One person can lift the chassis and roll it over to spray the bottom and sides. Just make sure you have wooden blocks or something similar to rest the sprayed sides on, otherwise it scratches the spring mounts, etc when you roll it over.
The diffs on my Jeep were the original Dana 41 at the back and Dana 25 at the front. Which leaves me with a question - the M38A1 only came out with Dana 44 at the back. The Dana 41 only appeared on the CJ3B until 1950. What is the story here? I'm not sure, maybe it was replaced (although I can't think that's the case, as the front diff and the chassis are in excellent condition), or the information might be wrong. Anyway, the springs can now be removed by undoing the u-bolt nuts. The leaf springs should have 13 leaves each - you can remove some leaves later when you have fitted your engine, and want maybe a softer ride. The leaves on mine has probably never been removed, much less disassembled, as the original grease had petrified and were filling the one centimeter wide groove in the leaves. OK, I wanted to do this right, and time was not a factor, so I took the springs apart, removed excess dirt with a wire brush on an electric drill, and sanded them down. A good tip here is to put them back together using alternate leaves from each side. If you had sag before, you will now have evened it out. If your springs sag too much, you will have to have them re-tensioned, or replaced with new ones (see the suppliers and parts section). After re-spraying them with a matt black primer, each spring should be greased before assembling it. This gives you much less friction between the leaves - which means better movement, which means better articulation. See the next section for a spring-over conversion - all I can say here is "LIFT"! The diffs need to be checked, preferably by someone who knows something about these things. I had a friend check them out without opening them, and the verdict was good. So I decided to leave it be for now, and see how they perform on the vehicle. I had to replace the seal on the front diff, as it was leaking a bit of oil. It's not a difficult procedure - just put the one side in first and hit the other side with a hammer to pop it in (not recommended for beginners!). Make sure you have diff oil in there after you have assembled and fitted your diffs. I sprayed them with the same matt black primer, after cleaning everything thoroughly, and lightly sanding it down. Some people fit chrome diff covers, but I've never seen them here. You folks in the states can buy them almost anywhere (see links section). The wheel nuts on the older Jeeps turned out the opposite way (only on some of the wheels - you try and explain that). So I had to replace the wheel studs with new ones. You can forget to try and find a wheel stud from a late model car/bakkie to fit there - the spline section is 16mm thick. The thickest I was able to find was the Toyota ones at 14mm, which just doesn't cut it. I found studs at Mickey's (WMH Dealers - see suppliers and parts section) that was a little bit longer. That was a good thing, as the older ones were too short to go through the new alloy rimes I got. The problem is that once you have the old ones knocked out, you can't get the hammer in behind the hub to knock the new ones in. Only thing to do is to fit the nuts (with a huge nut for a spacer) and pull them through by tightening the wheel nuts. You can use a puller to remove the hubs if you want - it makes the fitting of the wheel studs MUCH easier. This is also a good time to check your brake pads, slave cylinders, etc. I decided on a spring-over conversion to give me about 4 inches more lift. It works out much cheaper, and is very easy to do. How it works is this: originally the Jeep came out with the leaf springs attached underneath the axles. A spring-over conversion places the leaf springs on top of the axles Ta da! That's how easy it is. Well, almost as easy. You need to have a look at the bottom side of the axle to see what the attachment for the springs looks like. It's a pyramid shaped box approximately 100x40x40mm - I'll try and do a sketch for you. These need to be welded on top of the axle - fortunately there is a rectangular piece (bracket) there already, which makes it a lot easier.
The only thing to watch out for here is that on the front axle, on one side, the box has a cutout, for the u-bolt to fit in next to the diff (look at it, you'll see what I mean). You can overcome this by drilling holes for the u-bolt into the side of your new block. I had a friend weld these from 5mm steel, and it works perfect. I even used the same u-bolts (sanded and painted over, off course)! If you're going to have lot of lift, you have to rotate the back axle so the diff points a bit up from horisontal. In this case, you'll have to cut your blocks accordingly - you figure it out... Remember to replace the bushes for the leaf springs (Mickey at WMH Dealers again). These can be hard to find if you want to go for poly-urethane bushes. The shackle ends needs to be checked and if still fine, just cleaned and greased. Now the chassis can go back on the axles again, and Voila! - rolling chassis... The deciding factor here is what you want to do with your Jeep when you are finished re-building it. I wanted something for on/off-road use - definitely not an everyday vehicle (not with a V8 5 liter engine and the petrol price what it is!). I want to use it on weekends for 4x4 trips, a bit of bundu-bashing and at times something a bit more challenging. So I decided on All-Terrain tires. I'll see how they perform and decide whether to replace it with something else. Tire sizes...well, the options are limited to the amount of lift on your vehicle. Without lift, you should be able to fit up to 245/75x15 tires - and have just little bit of fender chafing. I think the USA standard would be 30x9.5x15 tires? The 265/75x15 tires are a little bigger (normally with an outside diameter of about 30.7 inches), but also wider. You'd have to have at least an inch lift and rims with a negative offset. If you decide to fit 16 inch rims, be prepared to look long and hard to find rims with the right nut configuration. Which, by the way, is called 5x140 - on account of it being 5 holes and 140 pcd. The tire shops have a clever tool to measure this. You can get the same outside diameter on a 15 inch as on a 16 inch rim, if you choose the right tire. My choice was alloy rims, mostly because the local manufacturers of steel wheels assured me that the 5x140 pcd configuration steel wheels was out of stock at all branches, and they're not sure whether they are going to make another batch next year. (Just a note to our overseas friends: We have a population of about 45 million in total, of which about 4.5 million belongs to the middle and upper classes. Of these, an absolute minority can afford, or are interested in 4 wheel driving. Thus - demand for parts does not warrant usually more than one supplier per type of part - sometimes no suppliers - like Jeep spares. So if you phone the two suppliers of rims and they say they don't have, you know there aren't any. Your mouths will hang open in surprise when you find out that they take the Chev and Ford engines from your scrapyards and ship them in containers for us to use and re-build. Oh, one other thing - our Rand is almost 8 to the dollar - try and import something at those odds.) Anyway, I found a set of second-hand alloy rims in good condition and will fit 245/75x15 inch tires on it. You might have to change the wheel studs - the standard ones are never long enough for use on alloy rims. Here again you can speak to Mickey at WMH Dealers (see suppliers and parts section) and ask him for the longer ones. To replace the studs you have to remove the brake drums and the hubs, then knock them in from behind with a BIG hammer. On the back wheels you might have to use a puller to remove the hubs from the axles - mine came off relatively easy. Just remember to line up the keyhole when you put it back on. You can get body lift by putting spacers between the body and the chassis. The easiest thing to do is find the V6 engine spacers (about 2 inches thick) and fit that to the chassis. Then lower the body on top of that and you have another 2 inches lift for free! you have to look at the angles for the propshafts and the lengthening of brake lines, if needed. The propshaft angle can be reduced by turning the axle - oops, I guess I should have told you this before you welded the boxes onto the axles. No problem - normally the increased angle does not make much of a difference (on my amount of lift, anyway). Go higher, and you'd have to turn the axles a bit. Engine, Gearbox and Transfer Case I initially looked around for a 350 or 351 cubic inch (about 5.7 liter, for the locals) engine. There are a few suppliers of really clapped-out engines (for rebuild only, they assure you), and this might not be a bad option if you plan to re-do the engine yourself (see the suppliers and parts section). To have it done - well, let's just say you might as well have bought a new engine. The parts are relatively cheap, and the labour not too expensive, but you're looking at about R10 000 for a recon engine. If you keep your eyes open, you might find a good second-hand engine for about R3000. This normally includes the 3-speed auto box. I was lucky to find a Chev 307 engine (from an Australian 1968 Holden Monaro) with the original 4-speed Saginaw gearbox, in running condition. It's a question of fitting it, then seeing what needs to be done when it's running. I will replace the plug leads with colour-coded ones, replace the valve covers with chrome ones, and replace the air intake with a chrome pancake one. The engine will be sprayed red in the Chev tradition. It already has a 4-barrel Rochester carb on it, which makes it push out about 180kW at 4600rpm (that's about 240hp!) without anything being done to the standard engine.
I will be fitting the engine and gearbox soon - I just need to have the transfer case and the gearbox fitted to each other first. I will then fit the engine, drop the body tub on the make sure everything fits where it should, then remove it again to prep and spray it. I deliberately left this till last, as any bumps and scratches that might occur now, will not matter. I need to put a power steering box on it, because of the bigger wheels. It was suggested to me that I use the Mercedes power steering, or the Toyota pickup steering mechanisms. I will be updating this site often, and I will let you know what I decided on, and how it worked out. You will have noticed on the photos that it was converted to a right-hand drive (yes, we drive on the left hand side of the road here), by cutting holes in the firewall for the steering column and pedals. I decided to change it back to left-hand drive and close up those unsightly holes. It might be a problem if you want to overtake, or get a ticket for the parking garage! |
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