Just picked up a L3750DT with loader and backhoe. Has 1700 hours, paints a little faded and surface rust here and there, but for the price I couldnt let it go. Runs good and works well. But I do have a few minor things to fix, fuel gauge doesnt work, temp gauge doesnt work, lights dont work and it has a intermittent no start issue. What I mean is that it wont start from the key every few starts, but if I jump the starter it spins and fires right up. I'm guessing maybe the starter solenoid. But theres also a Black wire that comes out of the loom right next to the starter that has broken off from something, does anyone know what its supposed to go to? Thanks for any help.
New to me L3750DT
- Thread starter tnp8841
- Start date
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
I don't have a wiring diagram for that exact model, so this is a guess.
Is there a wire going to the oil pressure sending unit?
It's located just above starter.
Is there a wire going to the oil pressure sending unit?
It's located just above starter.
fried1765
Well-known member
Equipment
Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
rbargeron
Well-known member
Lifetime Member
Equipment
L5450, L48, L3250, L345 never enough attachments
Great tractor - and welcome to OTT ! It's always nice to see someone "discovering" an L3 Kubota model - the L3750 is a very good machine ('84 thru '90) and is one of the models that helped K rise in the compact tractor market. They had high build quality and many are still going strong. Sometimes turf rubber like yours has can be a sign of a non-abused life.
The 4540 backhoe is an OEM model (zoom up the pic). It was back-heavy which limited FEL down pressure for back-dragging, but for digging a hole, there's nothing like having enough brute force to do the job.
Starter symptoms sound like the spade plug-in or the contacts inside the solenoid may be corroded and burned. They can be cleaned or replaced. Another kit that doesn't mention L3750 but probably fits is this one.
Here's another L3750/4540 setup - the shape of the dipper's top end identifies it.
Take care, Dick B.
The 4540 backhoe is an OEM model (zoom up the pic). It was back-heavy which limited FEL down pressure for back-dragging, but for digging a hole, there's nothing like having enough brute force to do the job.
Starter symptoms sound like the spade plug-in or the contacts inside the solenoid may be corroded and burned. They can be cleaned or replaced. Another kit that doesn't mention L3750 but probably fits is this one.
Here's another L3750/4540 setup - the shape of the dipper's top end identifies it.
Take care, Dick B.
Last edited:
Solid black wires on Kubotas are almost always grounds.
Edit: gauge problem may be a blown fuse. The two gauges have the same power supply.
Edit: gauge problem may be a blown fuse. The two gauges have the same power supply.
Last edited:
So yes its a Kubota 4540 Backhoe, things huge. As far as the black wire it went into the 3 prong plug on the alternator... one mystery solved. Ill have to look the manual to find where the fuses are at, I hope thats all it is to fix the gauges, the temp sender looks pretty new as well so hopefully it that simple. I did see that the back of the oil pressure sender is broke so I will be ordering a new one of those. Other than that most of the hoses, especially for the backhoe look pretty rough, nothings leaking yet but Ill have to work on getting those, I dont know if you can just order them somewhere or if its cheaper to go and have them made at a hydraulic shop.
Its my first tractor so its been very interesting and fun to learn doing simple stuff. Today I was dragging some downed trees out of the brush to cut up, probably be doing that for awhile.
The whole reason I got the tractor was, I have water issues from the hill back behind my house, I was getting ridiculous quotes that just kept getting larger and larger. So for half the price of some of the quotes I bought the tractor and Ill figure out how to do it all myself.
Its my first tractor so its been very interesting and fun to learn doing simple stuff. Today I was dragging some downed trees out of the brush to cut up, probably be doing that for awhile.
The whole reason I got the tractor was, I have water issues from the hill back behind my house, I was getting ridiculous quotes that just kept getting larger and larger. So for half the price of some of the quotes I bought the tractor and Ill figure out how to do it all myself.
rbargeron
Well-known member
Lifetime Member
Equipment
L5450, L48, L3250, L345 never enough attachments
The hoses can get looking pretty bad, but they're ok to use until they start springing leaks. The local auto parts store with a hose bench is ok for a quick single hose but is pretty pricey. Surplus Center can be cheap but usually doesn't have the right end fittings. My go-to for hoses is Discount Hydraulic Hose. On most Kubotas the hoses are 3/8" 2-wire type with 1/2" JIC female 37 degree swivel flares on both ends, some with a 90 degree bend. Follow the DHH website guide on measuring the length you need. Their prices are lower than the parts store and they ship in 2-3 days. Recently got 4 new hoses for the L5450's curl cylinders - $30-$40 per hose.
Last edited:
Welp I went to check the fuses for the gauges, the end of the terminal was corroded so i replaced that, now the warning lights at the bottom of the dash work but the temp and fuel gauge do not work still. Also got it stuck in the mud for the first time, is it normal that the backhoe cant drag it out or no?
Update i got it out, stacked a bunch of firewood under the rear tires, put tirechains on and slid a couple 2x8s under the body. After all that i was able to drag it out with a chain around a tree and the backhoe.
I did however break one of the hydraulic lines going to the left side stabilizer, can i just take it off with it in the up position, or is there a pressure bleed or something else? Also will i need to cap it? I wont run the tractor till its back on.
I did however break one of the hydraulic lines going to the left side stabilizer, can i just take it off with it in the up position, or is there a pressure bleed or something else? Also will i need to cap it? I wont run the tractor till its back on.
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
You'll need to lower it to the ground then remove the line.
Capping connections is always a good idea, but not required.
If you want to keep water and junk out of the connections just wrap the connection in a small plastic bag.
Capping connections is always a good idea, but not required.
If you want to keep water and junk out of the connections just wrap the connection in a small plastic bag.
Well went and got the one line, guy at the shop made it in like 5 minutes and charged me 83$. All the hoses look rough for the backhoe so thats going to be expensive. Got the new oil pressure sensor in, which is nice for piece of mind. Have a temp sensor on the way, now to just find where it is. Does anyone have the operators manual for the L3750? I have the service manual for the tractor.
Sounds to me like it's time to bite the bullet and replace 'em all. After the second or third one I figured I was spending as much on replacement fluid as I was on the hose. And if I was in a hurry and bought a hose locally, the cost doubled. Same experience on cylinder seals. You don't want to work on that boom cylinder but once.
As @rbargeron wrote, Discount Hydraulic Hose has references to figure out the ends you need and the length. You'll save on shipping when you order multiple hoses. I'd at least do all the BH or all the loader, if you won't be using one for a while.
It looks like OEM parts for your backhoe are unavailable. That's not bad though. You can remove the cylinder and take it to a hydraulic shop where they will disassemble it, replace the parts and reassemble it. Their parts usually cost less that OEM anyway.
Plan the job carefully. On my BT900, the boom had to swing to one side and the bucket, with the boom and stick fully extended, lowered below the plane of the rear tire bottoms. I used the stabilizer to jack up one side and blocked under the tire. This was to have clearance to remove the cylinder. Oh, and you may want to remove the lower pin and retract the cylinder before disconnecting the hoses, to minimize fluid loss/mess.
Replacement hoses have been covered before. You may want to consider replacing the hoses to save rework later. I can't tell by looking at the L4540 parts diagrams, but on the BT900 the space where the lines enter the boom is so tight I removed the pin where the boom pivots on the swing frame to replace the boom, dipstick and bucket lines.
Thanks for the info. Ill have to see about rebuilding it myself, these shops are $$$. Ive rebuilt a few motors, entire cars etc and in the words of Clarkson "how hard can it be?"
It's not hard, I've even done a few. The gland is probably set up for a face spanner, but you can use a pipe wrench, or some folks have made one, if you don't want to buy one. Ordinarily, I'd say loosen the gland before removing the cylinder, but that's not possible with your boom cylinder.
You'll need a stout wrench to remove the rod nut. Put the rod end back on the backhoe to hold it from turning while you remove the nut.
Use a pick to remove the dust wiper and rod seal. You may want to invest in a seal installation kit, available from all good on-line vendors (Amazon, eBay, etc). Be careful not to scratch the seal area.
Take the parts to a hydraulic shop and they'll fix you up. Make sure the rod is not bent or pitted. Reassemble and reinstall. The WSM will direct you to use expander and re-sizer tools to install the piston rings, but I don't know of anybody that does. Heat the plastic rings in hot water to soften and expand them, then carefully stretch them on.
It wasnt hard at all to pull out, just extended it to lay it pretty much flat on the ground with it about half way turned to the left, everything came right out. The only issue I am having is finding a seal kit anywhere. And no one locally rebuilds cylinders, so ill have to put a couple calls out tomorrow if I can find anyone who might know where I could get the seals.
Good deal. Did you get the seal loose/off? McMasterCarr has seals and stuff, but you can do better.
And of course it breaks when we have clear weather for a week or two. Oh well. I think im just going to send it out. I dont want to pull it apart and not find the stuff. If it wasnt the main lift i would probably just do it but at this point Id rather just have it gone through by a pro and hopefully not do it again.
When dealing with well-used equipment, that sometimes happens. I had a similar experience with my L35. I marvel at 'how did he (the seller) know the hoses were ready to fail?' But, after replacing almost every hose, repacking a few cylinders and a few other minor repairs, she's been reliable. There are a few other things I'd like to do, mainly replace the swing pins and bushings, but I have projects to do and don't need the backhoe much except for ballast.
For ~20% of what a new L47 cost (and I'd never have spent that much, so I'd be without), and some sweat equity, I have a pre-faded, pre-scratched machine that meets my needs very well.
I understand the attraction of new equipment, but I like to learn new things and this experience has taught me a lot about hydraulic systems.