This is copied from a website about heavy machinary. This describes working on a FiatAllis 31. You need something heavier than a 3/8 drive socket set to tear this baby apart.
Dozer repairs
I often get questions from people looking for parts or wondering how you fix one of these things. Our family joke is that when you want to fix this thing you have to get up in the morning with determination. Actually the technology of repair isn't much different from watch repair other than the fact that you need larger tools. The side skirts on the engine house open to reveal a 6 cylinder Cummins engine, which though a series larger than is typical of heavy trucks (the K series), it is familiar looking at least to anyone who has seen a Cummins and has no real secrets which make it different from other Cummins. The 6 foot diameter cooling fan on the front might give your a start though. Like most turbocharged Cummins, it is not particularly noisy (at least compared to the classic 2 cycle Detroit Diesels which have the highest noise to diesel ratio in the industry.) On the back of the engine is a torque converter coupled to a transmission by a short drive shaft. The 3 speed powershift transmission is bolted to the rear end case and the pinion extends from it to drive the bevel gear. Unique to Fiat Allis is a drop out clutch in front of the converter. The shifting sequence releases the clutch in front of the converter so the machine can shift without engine power against the converter. This provides a smooth and relatively jerk free shift even if you inappropriately make the shift at full throttle. The brakes are spring set --hydraulic released, and when the pressure blows down to release the master clutch, it also releases the brake pressure setting the brakes. This is a useful safety feature in that the machine will not run away if the engine dies or loses transmission pressure. Instead the machine stops. There is cavernous area under the floor boards around the transmission. This doesn't really mean that it is easy to access everything though. Mostly it means that things are so far away you can't reach them. Under the seat there is actually a 'manhole' big enough to allow a small man to crawl right down in with the transmission. For major service the cab is hinged on the back and can be tilted away to provide access for work in the converter and transmission area. Underneath there is a massive belly pan which yields access to the converter area (and which allows you to stand up under the dozer and look at the front of the transmission. The double reduction final drives have both a small gear running on a bull gear in the classic design, but also inside the bull gear there is a further planetary gear reduction.
If you need to break a track, you gently slide the master pin out (with the help of a 100 ton port-a-power) and perhaps some heat and a sledge hammer, and lay the track chain out on the ground. Swing frame removal isn't much different from a small dozer. The sprocket has an outboard bearing bolted to swing frame, and the angle brace underneath is bolted up with 4 bolts just like many smaller dozers. some assistance here is an 1.5 inch square 3000 foot pound impact wrench and a socket set to 3 inches or so. The classic 1 inch drive impact wrench such as is often around to change truck tires and the like only kicks up 1000 foot pounds of torque and won't do much except make noise on bolts of this size. This also implies that your shop truck needs a real air compressor because these large impact wrenches use 25 or 30 CFM. We use a 2 stage 15 CFM compressor with a 60 gallon tank with satisfactory results. This, of course, won't sustain the wrench, but unless you are tougher than we are you won't mind resting up between bolts while the compressor catches its breath.
The entire sprocket, final drive, planetary assembly can be unbolted from the side of the rear end housing and removed from the dozer as a single unit, by simply breaking the track, unbolting the swing frame and jacking the dozer up about 3 and a feet so the bottom of the sprocket clears the top of the swingframe. The bolt circle for unbolting the final is accessible with a long extension through a small hole in the sprocket. The plan is for the sprocket to be rotated (with machine power) while the bolts are successively removed. This works quite well. Life is less simple if the machine is out of service or the final is lockup up and won't turn, though it is reportedly possible to get the bolts out with a slug wrench and a hammer.
5/27/2003 9:26:59 PM
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Originally Posted by Swoop
or is that need 
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