buying used. you need to have know how to fix the tractor, it doesn't what brand or model, used = maintenance and repair.
with used units, tire tread can be a big deal, tires are costly, 50% tread to me is balled. there is a huge difference in traction on new tires vs older tires.
oil leaks, hyd oil leaks, etc... if ya looking for a backhoe, then it is doubtful you will find one that doesn't have a hyd oil leak some place, and engine may have a leak some place as well.
4x4 / MFWD, is not always what is cracked up to be, 2WD can get a lot done, a good experienced operator and some experience on a machine can do wonders.
all the hydrualic cylinders from FEL to backhoe to other, if you turn on tractor let it warm up for a couple minutes and then run it hard for say another 15 minutes and work everything to point warm hyd oil gets into all the cylinders. then raise everything up in the air, then turn off machine, hopefully everything stays up in the air, if it does not it means seals, or hyd pump, to hyd valves may need to be rebuilt with good seals.
double check "left and right rear break pedals" to make sure they stop the unit or need adjustment.
double check the grease fittings on mower deck to axle bearings on the front, to other places, to see if things were greased.
see if the bolt to drain oil on engine has some wear marks on it.
a freshly clean engine and tractor that was power washed and scrubbed, i get uneasy about. dusty, oil, greased up unit looking ugly. no biggy, but just cleaned *arghs*
see if they have "shop manual" for the tractor. good sign that maintenance was done, and things repaired as needed.
get the shop manual for the tractor you end up getting they are expensive little gems, but they are gems, and normally worth all the diagrams, code notations, and detailed instructions for tearing apart / putting back together and what torque settings for this or that, etc....
never buy site un-seen, physically drive there and test run the unit.
example with the ford 555c TLB (tractor loader backhoe) went online criaglist, tractorhouse, looked up a bunch of units that fit my needs and planned a day trip to go look at all the units. there is a surprising difference amongst all the units, from tire tread, to oil leaks, to just overall how much damage and abuse a machine had, various bushings and pins worn, extremely loose front ends, hardly any brakes, engine oil and hyd oil look extremely old and not been changed in who knows how long. dents and bangs, oil filters and air filters, that looks like originally new 10 plus years ago when machine was new, dry rotted tires, all lights busted out, if it was a cab if it actually had any windows that were not busted out, to emergency brake wire cut on purpose it looked like on one unit, etc...
i am by no means a mechanic, just a farm bozo that had to learn, or do without. and the day trip i took to look at i think total 13 units. was an eye opener. and test driving was even more so on some units was rather scary.
