First crawler: Need advice

[Tennessee Wayne]

May be about to get my first crawler. I know absoutely nothing about them. Have plenty of expierence with the Dubuque wheel tractors.
What do I need to look for?
Its a 420 with the blade mounted outside the tracks. Manual angle by pulling out a pin and sliding it back to another hole. Man says its in good condition. Wants $3500. Still on 6v. Is this a biggie?: It has several loose bolts that hold the pads on. Also not sure how deep the tread should be on the pads. Man says steering clutches are good. Also what are the foot pedals for? Do they do the same thing as pulling back on the levers? Thanks for any advice.

[Lavoy]

1" on the grousers is considered 100% worn by the book, but is easly runnable for a lot of years.
Pedals are the same as wheel tractor, engine clutch and operating brake, steering brakes are coordinated with steering clutches and handled by the two steering levers.
Price sounds okay, but take a flashlight and look down in the inspection and adjusting covers on the steering clutches for any sign or oil, or lots of rust.
Lavoy

[Tennessee Wayne]

Thanks, will do.

[gregjo1948]

Check remaining adjustment on tracks. Check spockets for wear( if pointed at the ends--very worn) Feel the bushings on the chains where the spockets ride-- if large flat spots or holes thru--they're shot. Lift the front of tracks with the blade max down-- push&pull sideways on the front idlers (wheels) this will tell if the bearings are shot allowing the track to come off while driving. Just a start at things to look for on a dozer. There are still the same things in the drive train to look for that are on your tire machines too. Have fun! gregjo1948

[Willyr]

When looking in the inspection hole. Look for the castellated nut (nearest to you when looking in the square hole on each side of the seat). Hopefully you will see the nut taller than the stud (meaning you have adjustment left). If the nut has been wound down all the way that means when the brakes need adjustment you will need to replace the bands.

Sit in the seat. Correctly adjusted levers will only move 1-3/4 inch of travel. More than that and they are getting out of adjustment.

Start the tractor. Ask the owner if there is a bank nearby you can drive up. Get the tractor on a hill (with the blade up) and push the pedal in to the floor or to where it stops. Hopefully you can apply the brakes and the tractor doesnt roll back. If the brake doesnt hold the tractor will roll backwards, so dont go up a really tall hill, a 4 foot tall hill is enough.

Now find either a big tree or if you can set the blade into that pile of dirt you just climbed. What you want is something that is going to resist getting pushed. What we want to see is in first gear, that with a load that wont move, ground speed is zero, yet the tracks still turn and the engine doesnt die. You only need to do this for about 3 seconds. Both tracks should turn, engine rpm will drop slightly from the load, yet these tractors are fairly light. So track spin is fairly common on too great a load. Track spin indicates that the track clutch on each side are still good. A bad clutch the track will stop turning (dont use the levers or the pedals on this test).
Also if the engine has issues the engine will die instead of staying running.

Take the oil breather off while its running. With a rag, cover the hole. Can you gently hold it down? Or does the air coming out try to blow your hand off the pipe? If the latter you have blow by in the rings. Look at the underside of the oil cap. It should only look lightly oily. If milky you have coolant issues (either head gasket or a crack some where).

Go to the radiator. With the engine running and the radiator full. Does it have antifreeze in it? When the engine starts and you remove the cap, does the coolant only circulate? Or does it want to geyser out of the radiator? If the latter another sign of head gasket issues.

Look at the track front idler. There is a threaded rod on the side. There is a set of nuts on this threaded rod. How close to the end are these nuts? How much track slack do you have? Place a straight 8 foot board across the top of the tracks. If you have a center top roller, average track slack (max) is about 1-1/2 inches.

Feel under the tracks. You want to feel the pin. Does the pin feel round? Or does it feel egg shaped?

Does the sprocket valley look like a correct half circle? Or does it look like a squashed "0" and the teeth are pointed? If pointed it needs sprockets.

I would help you more but the wife just called and she needs to go see her Mom that just died.