1961 Cat d6

This machine is a D6B SERIE 44A with d333 motor

No receipts sounds like a ruse but you never know. Inspecting the engine (assuming that's what was rebuilt) might provide some clues as to whether it's been apart lately but not who took it apart. The usual things to check are a) does it start, move, steer as expected, b) undercarriage condition, c) leaks, d) movement where there shouldn't be such as in the track frame to rear hub connection / is the outer hub centered over the sprocket (turn the tractor left and right and note how much the track frames move), e) condition of fluids, f) hydraulic "power". Craig, who's a D6B expert, notes that parts are NLA for the hydraulic control so it needs to be in good condition to get some use out of it

dose it still have a pony start? as most d6B had a new style pony that where know as buzz bombs. they cam apart a lot of the time I think they ran 5000. lest just say parts are not very common

Hello Scott, That D6B seems to be a fair deal at that price. I don't think anything has been done to the engine for a long time. If the tractor operates and turns okay see if he will move it to your place for you or if he will take a little less.
Look at the amp gauge and see if is showing charging after starting the engine. If it isn't you will have to convert it to a 24V alternator in the future as the 24V generator is no longer available. If you try to have the generator rebuilt please note that the pully nut must be torqued to no more than 30 ft. lbs. as that preloads the generator bearings. If the nut is over-tightened the generator will have a catastrophic failure after only a few hours of operation(Ask me how I know!!) The generator must also be "polarized" before use.
You should only use AW32 10W oil in the hydraulic system, 
The most important thing for you to do is become a "paying" member of ACMOC. This will allow you to access the ACMOC library. The library contains all the books on the basic D6B, the hydraulic system and the blade. The Operation and Maintenance Instructions(OMI) is the most important manual to read before you operate the tractor.
This D6B is equipped with direct electric start.
The D6B "Buzz-Bomb" starting engine actually spun to 6,000 RPM when the throttle was set to "high-idle" to start the diesel engine!
Good Luck!
Craig

 

Get a kick out of all the ' Cat 'exspurts "and their old wife's tales.
That starting motor never was supposed to turn over 5050 RPMs on fast idle, most were set at 4000 RPMs.on other motors.
In any case I would say a motor that may be 60 years old that still works can't be all bad.
Bob

Hello Scott, After I looked at your photos again I noticed that the left track adjuster must have failed and is now being held in place by a block of wood. That should be fixed if you buy it.
Craig

 

There are more questions than answers on evaluating a tractor by picture. The blade itself says used and used hard. But no other big signs of big time abuse show right off. One thing I see in the same picture as the spacer block in the track adjustments shows the best in, right above the front carrier roller track looks to not be flexing. But looking in person is the only way to know for sure, a real guess from a picture. Which is good in it generally indicates more life left in the rails and pins and bushings. But a pain to fix. But track adjustment looks out to the end, not good. So look at pins and bushings to see how out of round they are.

What do you know about the operation of the earlier Cat's ? The release the steering clutch and apply brake to make turns. We need Sasquatch to do a you tube rather than explain it each time. But you cannot know if you don't get a chance to learn, so don't be afraid to ask more questions. But you may know a lot already, so not trying to put you down ether. If it turns and pushes ???????? Then worry about the paint.

The seller needs to do something more to prove any work has been done to that tractor. But on the other hand moving it 20 miles versus 200 miles adds up fast too. So check oil levels in transmission, final drives, hydraulics and the engine. My motto most days is a leaking final drive is one with oil in it, rather than being dry. But big leaks need fixing.