I see a lot of the Komatsu's for sale at a good price, are they any goog?
Ash,
Not sure if the Komatsu's are any "
goog" but for a small dozer there pretty good.
I have a D20A-6 Komatsu, it's a very small, light weight (9K lbs) dozer. It's very easy to work on.
Take a look at this thread for the complete history of my purchasing, maintenance and user experience with it.
Not sure what type of work your going to use it for as you did not mention your intended use or the soil conditions you might be up against.
What to look for -
Undercarriage wear (all the parts that make it move or come in contact with moving parts).
Rear Sprockets - pointy(bad) broad & flat (good)
Front tensioner idler roller and track rollers - are they nice & round or, cupped / U shaped, or out of round.
Track Link Bushings (the round part of the track chain that is driven by the sprockets) Are they symmetrical round? or do they have flat spots?
Track link wear (slop in the bushings) - are the tracks properly tensioned - is there a little sag in them or a huge amount of sag? Take a look at the track tensioner mechanism, it is usually a cylinder rod that pushes up against the front roller to take up track slack, how much travel is left to keep the tracks from excessive sag. You can tell by looking how many inches of travel are left at the front of the track rails.
Leaks - any leak anywhere is not good.
Hydraulic cylinders and rods, are they leaking? Rods pitted / gouged? Rod seals leaking ?
Steering breaks & steering clutches -
Drive it around turning left & right, get a feel for how far each lever has to be pulled back to steer it.
Find a place to lower & bury the blade, BOTH tracks should continue to spin at the same rate, this will tell you the steering clutches are still good, or at least have some life left in them.
Pull both steering levers back about half way at the same time so as to dis-engage the steering clutch but not so far that it activates the steering breaks, both tracks should roll to a stop, and the engine should not bog down, then slowly release one lever, the dozer will be powered by one track but should still go in a straight line. Repeat with the other lever to make sure the dozer will go in a straight line by being driven on only one track.
Komatsu parts - new parts, they are available from Komatsu dealers. There is a dealer locater on the Komatsu web site. I have not yet found a part that I needed that I could not get. There are Komatsu parts on e-bay. An plenty of salvage equipment dealers, brokers etc that sell used parts off disassembled units.
Be patient look for a good deal and a good working machine that needs little or no repairs. Parts prices for dozer's are shocking to say the least, Dozer's are money pits. When the time comes to replace major parts, (all parts are major) you will not believe what some things cost, so be prepared for the shock of your life.
Larry