M4500 strengths and weaknesses

JohnDB

Active member

Equipment
M4500DT
Jun 9, 2018
373
62
28
NZ
I had a couple of conversations with a guy who came up through the ranks from mechanic and ran a small Kubota dealership last century. I was wanting to know about stuff to watch out for on my M4500DT. He had some interesting observations that I thought were worth sharing with anyone contemplating buying or operating this particular model of tractor. This isn't about tractor specs and the usual stuff in maintenance manuals - it's about the extra stuff that years of experience with this model teaches.

Stuart's observations:

Performance
Short stroke engine needs to be revved to get the power otherwise it bogs down quickly. Not a torquey engine at all. Don't worry about low compression as long as it starts and compressions are even. Needs a good amount of glow plug to start. Always had a fair amount of engine blow-by, even from new. The clutch can sometimes emit a groaning/vibration just as it's taking up, but it's common in them, not a problem. The clutch is heavy duty, rare to wear one out. There were rumours about "weak front axles" spread by competitors but there were no problems with overloading axles even when front end loaders fitted. There was no front axle rating. Overall a very reliable tractor.

But watch for ...
1. These 6 cyl engines have a long narrow head, which makes them more susceptible to cracking than engines with fewer cylinders if there are cooling system problems.
2. Cooling system vigilance - in addition to the usual belts/hoses/cap/rad fins etc:
Water pump bearings do fail from time to time; check for radial movement of the fan If there's any play at all (one test is to grab a fan blade and heave on it in all directions, do this several times, both sides - if there's even the faintest sense of movement, investigate). Dry or worn pump bearings can create a high pitched tinkling noise just descernable against normal engine noise.
Radiator cap should be 13.8 or 14 psi, sometimes people fit the more common 7 psi type - not a good idea.
The foam packing between the radiator and the exterior panels deteriorates over time - it's important for hot weather/hard work because it stops the air recirculating around the radiator.
4. Hard starting can be caused by faulty glow plugs, but resistance check is good indicator of being OK. Even in relatively warm conditions these engines need about 25 seconds glow to start from cold.
5. Bottom seals on front wheel drive knuckles can leak oil. If nothing is done about it the gear system will run out of oil (it's only about a pint) and wreck the gears. There are 5 level plugs to check on the front drive axle so people sometimes assumed there's enough oil based on looking at the wrong level plug.

Electrical
These tractors had no starter relay so the high current going through the key switch and starter switch gave the contacts hell and sucked voltage. Fit a starter solenoid relay if any starting problems.

Tail light and indicator lenses; if you break them, there's no known commonality with Japanese cars or trucks, they were Kubota specials. The reversing light is from a Mazda ute.

Hope this is useful to someone in future. Someone else with a lot of experience with this old model of tractor might have other useful stuff to add to this thread or debate what I've been told :)
 
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