A WD-45 is a great lil tractor. Every single part is available from a huge number of aftermarket vendors, Ebay has a ton of stuff for them, and AGCO still carries quite a bit of stuff for them too.
Strengths: Dirt simple to work on, they are pretty good on fuel usage, lots and lots of power, small size they are fairly stable if you load the tires, good visibility, very easy to modify (12 volt charging, electronic ignition, more power etc)
Weaknessesesses: they have a habit of popping out of gear (easy fix) go down a hill (NOT A STEEP ONE!!) and drop it down to idle a couple times to try to coax it to pop. They get knock-kneed in the steering, esp. the narrow fronts, get it onto a smooth hard road and drive it in top gear to see if the front wheels wiggle, also check how much the steering wheel will turn before the front wheels will start turning. (the fix requires a shim and some gasket material) They foul the plugs in about 3 minutes, and they seem to go thru points kinda quick and it is very easy to get the carb dirty and they run like crap fast. a loader on a wd is useful, but not much better than a 4 yr. old with a plastic shovel for any real work. Hydraulics are power up gravity down, no 2 way at all (from the factory)
The brakes are absolutely miserable to replace (lots of em are non-existant) they also leak fluids they did when new right on the showroom floor. Lately new oil filters have an improper design and they wont build oil pressure but the proper ones are available still almost everywhere.
The hand clutch stops the differential gears from spinning only, pto and hydraulics will still run. foot clutch will stop averything except the motor. when you check the hand clutch, pull it back and when you push it foward listen for a loud metallic snap, (the snap is a good thing)
Also be careful it is not a wd tractor. A wd45 will have a curved shifter handle, a "snap coupler" bell under the belly just ahead of the PTO gear housing, the motor on the "passenger side" should be solid with no thin metal plates bolted to it above the distributor the whole length of the motor 8"x24"ish. the serial # is the best way located back axle drivers side stamped on a flat pad facing straight back under the brake inspection "foot rest" cover. lots of folks stuck wd45 stickers on a wd and sold em for more $ they look the same. Check out
www.ytmag.com for more info on em.
I'll toss in a pic of my hotrodded '45