First I rented a small 10,000 # excavator and learned to clear ditches. By the time ditch was cleaned, I was determined to own some big toys. Started with a Hein Warner C 14a that was badly used. Then acquired a D8H dozer that was also well used. Learned to use on my own. Both accomplished what was needed. Cleaned/cleared several acres of ground and 3 plus miles of drainage ditches several times. It was a good learning experience on both. Both pieces got drowned two times and were brought back to life each time. Everything sort of still worked when sold last year. The dozer had probablly 2 feet of slop in blade two foot high and rubbed the tracks some. Tranny still shifted and started by jumping solenoid on starter. The unfixed exhaust leak really killed it power wise at the end. The front idlers and all rollers were worn out on Hein Warner when acquired and only got worse. When sold, one idler was not functional and pumps marginal. The hydraulic leaks kept my busy and caused several pump failures. Still remember fighting the floor pan to get to track drive hoses, while swimming in 70 gallons of lost fluid. I remember the bucket, stick, and boom cylinders were super strong for it's weight. It could take down tress the Hitachi EX 270 has trouble with now.
Oil leaks were not fixed until exceeded 5 gallons per hour. I had a very good supply of Witches oil (unknown mix but mostly 15-40 at 50 cents a gallon) that worked good enough.