MT372 issues

[kempfat]

Hello all! I seem to be having issues with my Mitsubishi MT372. The first issue is, I can't get it to start. I know that it is getting fuel, the compression is good, However, I am concerned about the glow plugs or the wiring in general. I have found a yellow and blue wire that looks like it is coming from the starter but leads to nowhere. Is it possible that the wire was pulled from the back of the switch? My young'ns climb on it and pretend to drive it... My second issue is the hydraulics. My 3pt hitch is stuck in the up position and I have tried everything to get it down. I have tried the speed knob below the front of the seat. I have drained the fluid, checked the filter, replaced the fluid with universal hydraulic fluid, checked the hydraulic fluid pump, and bled the system of any air. And nothing... (Just a side note. Don't squat down in front of the hydraulic pump with the lines cracked and have someone bump the key!) Hydraulic fluid does not wash out of clothes! Any help would be greatly appreciated!

 

[skylarkguy]

If you need a wiring diagram send me a pm and we'll figure out how to get you a copy of mine. That might help with the wiring issue. I have an mt372 as well.

On the 3pt i had a similar problem. The previous owner decided to cycle the 3pt just hours before i picked it up. There was no implement on it. It had a bunch if crud in the top if the cylinder and it jammed up pretty tight. I had to disassemble it and smack it out with a brass punch. I lightly honed the cylinder and replaced the o-ring. Not too difficult especially with the manual.

 

[284 International]

...I can't get it to start. I know that it is getting fuel, the compression is good, However, I am concerned about the glow plugs or the wiring in general.

The wiring diagram I have for an MT372 shows yellow with blue wires from the oil pressure sender up to the warning lamp. It shows black with yellow and black with white wires to the starter, and some other of indeterminate color coding. (B AV2 is what I *think* it says). I'm not entirely convinced of the accuracy of the manual, however: The legend says "Blw" stands for wire that is "Blown." I'm strongly suspicious that there may have been some mis-translation afoot in some portions of the manual...

My questions are these: How have you assessed that there is fuel arriving at the cylinders, and how do you know the compression is good?

Having said that, I agree it is most probable that your glow plug situation is the likely culprit. I would get a tester (Of the light-bulb or multimeter type) and test for continuity on all the glow plugs. Test to the center of the electrode with the other end grounded on the battery negative terminal. If there is no continuity, the glow plugs are bad.

After that, it is a straightforward assessment: Power must be delivered from the glow plug activation switch to the plugs. Follow the feed wire back to the switch, and test for power from the battery TO the switch. If there is power, but it doesn't get to the glow plug feed wire, then you have switch trouble. A very short workaround is that if the switch will activate the starter motor, the switch obviously has power.

Even with bad/non operational glow plugs my tractors will always at least smoke. If there's no smoke, you should check your fuel delivery situation.


I had the jammed lift cylinder situation as well. Instead of doing it properly, as skylarkguy did, (Typical of Buick owners, in my experience ) I did it in a more barbaric fashion. I secured a piece of chain between the lift arms, wedged a large 4x8 under the rear of the tractor and across the chain, then bounced my 250 pound self on the end of the 4x8.

It let go with a sudden bang and crash, and I'm actually rather lucky I didn't injure myself in my foolishness. I would actually be worried about perhaps damaging the tractor, as well, with the tremendous force being placed on the tip of the lumber.

After freeing it, however, it does operate fully and smoothly. The cylinder continually leaks down, however, I'm sure because I have not yet replaced the seals and honed the bore. I wouldn't recommend this method, but I have done it, and it's an option of sorts. Make sure the lift lever is in the fully lowered position, and that the speed adjuster is at minimum restriction.

Good luck, let us know your results!

 

[kempfat]

If you need a wiring diagram send me a pm and we'll figure out how to get you a copy of mine. That might help with the wiring issue. I have an mt372 as well.

On the 3pt i had a similar problem. The previous owner decided to cycle the 3pt just hours before i picked it up. There was no implement on it. It had a bunch if crud in the top if the cylinder and it jammed up pretty tight. I had to disassemble it and smack it out with a brass punch. I lightly honed the cylinder and replaced the o-ring. Not too difficult especially with the manual.

Skylarkguy, Thanks for the info on the 3pt. I will have to check that out when the weather clears up a bit. Since I don't have the manual in my possession, could you describe the steps you took to free your cylinder?
As for the wiring, I am waiting for the manual to arrive from my Father-in-law. He was the prior owner. He never used the tractor so it is in really good shape. The guy that owned it before him must of had a problem with the wiring because the wires in the dash area are hanging out the bottom. Some are taped up and some have wire caps... NO GO in my book. I think I'm going to remove the entire harness and build a duplicate harness using new wire and connectors. It'll probably be cheaper than the $150. quoted to me for a refurbished old harness. I'll use the manual as a guide and photos of refurbished ones (just for the wrapping). I take photos of the process and share. I'll also make a parts list of where I acquired the materials and the cost related.

Thanks for the help!

 

[kempfat]

The wiring diagram I have for an MT372 shows yellow with blue wires from the oil pressure sender up to the warning lamp. It shows black with yellow and black with white wires to the starter, and some other of indeterminate color coding. (B AV2 is what I *think* it says). I'm not entirely convinced of the accuracy of the manual, however: The legend says "Blw" stands for wire that is "Blown." I'm strongly suspicious that there may have been some mis-translation afoot in some portions of the manual...

My questions are these: How have you assessed that there is fuel arriving at the cylinders, and how do you know the compression is good?

Having said that, I agree it is most probable that your glow plug situation is the likely culprit. I would get a tester (Of the light-bulb or multimeter type) and test for continuity on all the glow plugs. Test to the center of the electrode with the other end grounded on the battery negative terminal. If there is no continuity, the glow plugs are bad.

After that, it is a straightforward assessment: Power must be delivered from the glow plug activation switch to the plugs. Follow the feed wire back to the switch, and test for power from the battery TO the switch. If there is power, but it doesn't get to the glow plug feed wire, then you have switch trouble. A very short workaround is that if the switch will activate the starter motor, the switch obviously has power.

Even with bad/non operational glow plugs my tractors will always at least smoke. If there's no smoke, you should check your fuel delivery situation.


I had the jammed lift cylinder situation as well. Instead of doing it properly, as skylarkguy did, (Typical of Buick owners, in my experience ) I did it in a more barbaric fashion. I secured a piece of chain between the lift arms, wedged a large 4x8 under the rear of the tractor and across the chain, then bounced my 250 pound self on the end of the 4x8.

It let go with a sudden bang and crash, and I'm actually rather lucky I didn't injure myself in my foolishness. I would actually be worried about perhaps damaging the tractor, as well, with the tremendous force being placed on the tip of the lumber.

After freeing it, however, it does operate fully and smoothly. The cylinder continually leaks down, however, I'm sure because I have not yet replaced the seals and honed the bore. I wouldn't recommend this method, but I have done it, and it's an option of sorts. Make sure the lift lever is in the fully lowered position, and that the speed adjuster is at minimum restriction.

Good luck, let us know your results!

284 International, Thank you for the tips. First allow me to answer your questions on the delivery of fuel and the compression.

The fuel: As I was checking for an air locked fuel system (that was my initial theory), I started at the tank and worked my way to the fuel pump breaking the connections along the way allowing the fuel to go from a spurt to a stream. After ensuring that the fuel was making it past the filter and to the pump, I loosened and removed the injector lines and bumped the key until the fuel came out without any anomaly (air bubbles or sloppy spurts).

The compression: The compression is just a guesstimate. While I had the glow plugs removed I bumped the key to test for power to the plugs. While I had the key turned I noted that the compression didn't sound tired. I also noted that the fuel was being blown from the cylinders and out of the glow plug holes. I plan on going to harbor freight to get a compression test kit ($29.00) for a cheap one. The compression should be around 400 Lbs if I'm not mistaken.

My tractor will smoke when trying to start as well. Sometimes it even acts like it is about to start but never quite makes it.

As for the chain idea... I'm glad your okay! I think that I will stick to Skylarkguy's method of attack! I'll keep yall posted with pics and prices of materials when I get started. The weather is pretty crappy here right now and I don't have an enclosed area to work in... yet.

Thanks for the tips!

 

[284 International]

The compression test isn't a bad thing to do, but I would buy a cheap test light or multi-meter at Harbor Freight while you're there, if you don't have one, along with the compression tester, and inspect the glow plugs first. My Mitsubishi machines are outstanding little tractors, but they really do need their glow plugs to start, even in warmer weather. If you're not getting heat at both of them, it wouldn't surprise me at all if even a brand new engine wouldn't fire off.

It sounds as if you have bled the fuel system well. I have a Satoh ST1440, which is the MT373. I had similar non-start issues as you, and it took some sorting out of the glow plugs, even in warmish to hot weather, to get it to start. Even after I had initially bled the system, I still get episodic "burps" of the engine missing one cylinder firing, presumably from an air bubble somewhere, for a few minutes after starting the machine after an extended period of time. (Say, several weeks.) After it has burped the micro-bubbles out, the machine starts much easier, even from a cold start. I mention this only because you may find that after you get the tractor started the first time, and give it an "Italian tuneup," it will start easily even after cold-soaking.

I like to start easy and work toward hard things, and cheap to expensive. If you can find the glow plugs are deficient, they are relatively cheap and easy to fix. Finding issues with the compression is complex and expensive to repair, and will only matter if the glow plugs and fuel situation are under control.

Don't give up, you'll get it running.

 

[kempfat]

284 International,

Thanks for the info and the vote of confidence! I'll get'er done!

 

[skylarkguy]

Kempfat, the basic removal is: the seat, the tool box, the fender brackets, the banjo bold holding down the hydraulic line, then 8 bolts, holding the hydraulic case. You don't need to drain the fluid to do this but I suspect you might want to after knocking a bunch of crud in there. The case will be stuck on with sealant.

After dumping this onto your work then take off the lift arms, the bushing set bolts the ram shaft, lift fork and piston rod. Remove the cylinder head (the part with the drop speed valve control) the piston should be in there. At this point you will have to decide the best way to forcibly remove the piston.

Your manual should have a section called "hydraulic system" this procedure is outlined there. If your manual doesn't let me know and I can send you a photo copy of the pages of mine.

284 International, thanks for the compliments, I think we should nominate your approach as the Archimedes method..."Give me a lever long enough and a fulcrum on which to place it, and I shall move the world."

 

[kempfat]

Hello All!

I finally got some time to dive into the hydraulics issue on my MT372. Here are some photos of what I'm dealing with. As you can see, the cylinder head is seized in place. I have tried removing the metal plug on the back of the housing and used a rod and hammer to try and beat the head loose. I have also sprayed the head with penetrating oil and let it set for a while and used a rod to try and beat the head loose from the inside... nothing... any suggestions would be greatly appreciated?



Thanks!

 

[skylarkguy]

Well you are pretty much there. You'll want to remove the piston rod from the lift fork. It should be a cotter pin and shaft, and it should still be loose. You can then get something in there to drive the piston back forward in the bore. You should take off the cylinder head (the part behind the drop speed knob) this will allow you to get a hone in there to clean it up a bit once the piston is out.

When you drive that out you will need a pretty big hammer (5 pounds probably-that claw hammer in the picture isn't likely to do it) and a large brass punch. Just make sure you use the brass punch. I'll freely admit that I was hesitant to whack on that sucker, I showed it to a guy at a local tractor repair place in about 3 smacks with the hammer he freed it...No charge...So be assertive with it

For a hone I just used a regular 3 stone cylinder hone any auto parts house should have one. Don't go crazy on honing you just want to remove any crud, not resize the bore too much. Get a new o-ring and you are golden.

Unrelated...those weights you have on the back axle are pretty interesting.