L3130 - suspected crankshaft damage - how to remove engine

[jiggseob]

Spent the day finding switches, got no where with making the tractor move. Under the body-pan there are several switches, which one can see by peering under from the rear. Reasonably good access is acheived by removing 2 nuts and 4 bolts that hold the ~20" square piece of body-pan that holds the seat. Then there is much better access to the workings of the HST and 3pt linkages and switches. Unplugged the switches one at a time, removed them, tested them using meter and checking for state-change when moving the switch. No progress. Still cuts-out when HST toe-and-heel rocker is moved more than a smidgen off center.

I did find a carefully tied loop of baler twine on the left side of the tractor under the body-pan just inboard of the rear wheel, whatever it was tying the twine had rotted away and was no longer tying. Something tells me that baler twine rotted off whatever it was holding is pointing to my problem. That certainly fits with the way the previous owner ran his equipment. Further down that rabbit hole tomorrow.

On this particular engine and fuel pump setup, applying power to the fuel solenoid moves the fuel delivery rack from "off" to "inject fuel". Removing power from (unplugging) the fuel solenoid allows the return spring to move the fuel delivery rack back to the off position. To "hotwire" around the problem, I could connect the fuel solenoid directly to 12V power. Maybe use baler twine for part of that setup... But seriously, that would get things beyond this point of hangup, and allow further progress and further troubleshooting of who knows what further problems.

It needs a new alternator. Way back on post-1 of this thread I mentioned two dead Kubotas found in the bush of a lock-stock&barrel farm purchase. That other Kubota is running around the farm doing chores and working fine. This tractor I'm working on does not charge the battery while running, and the battery light is on. After checking fuses and the obvious stuff, I swapped the alternator off of the running chore tractor onto this tractor, and it now charges and the battery light is out. So swapping on a known-good alternator shows me its time to order an alternator. I'm getting good at R&R alternator.

 

[jiggseob]

Spent another few hours chasing that switch/wiring problem that turns the fuel-on solenoid off when the HST to--and-heel rocker is moved more than a tiny smidgen off center. Still no where. Got some technical assistance from a John Deere tech that was at the farm dealing with the 612 sprayer engine throwing codes and de-rating. The circuit diagram in my WSM needs the use of a magnifying glass to see the little stuff. John Deere tech thinks it may be the HST Pedal Switch. Ran out of time, tomorrow may swap that switch with the one on the L3540.

 

[Nicksacco]

Progress nonetheless.
I ended up enlarging wiring diagrams on my printer. This is especially helpful where pages change, Wiring diagrams are made for 20yo eyes!

If you've found the HST pedal switch, I'd be surprised if it wasn't bad or bad wiring. Goodluck.

 

[jiggseob]

Re-checked ignition switch and hydro-pedal neutral switch today. No progress.

Drove tractor at a snail's pace out of the shop to the side-yard and pulled back the tarps on the LA723 loader. Plugged in the 4 hoses, and the boom-lift does not work at all. Bucket lift works, but theres one holey hose on the right bucket tilt cylinder, not un-expected having sat outside unused and un-maintained for 15+ years. What I did not expect is to find two boom lift female couplers - on the loader-hose side - failed. On this tractor, there are 4 male couplers sticking up off the control valve, and the four loader hoses couple on. The typical male coupler has a pin or ball sticking out the end, and the typical female coupler has a pin or ball on the inside; when coupled together both balls or pins push on each other and allow fluid to flow. In my case, the pins on the insides of both female couplers were broken, and the mating pins did not press on each other to open, and no fluid flowed. So I need two replacement female quick couplers.

This is a picture of the male quick coupler sticking out the top of the loader control valve. I need female couplers that mate up to them. Other than the dealer, does anyone know what to ask for at a hydraulic shop? The couplers we use on the farm are "pioneer 3/4" and "pioneer 1", and these are not them. The thread to the hose is 3/8 nptf.

 

[Nicksacco]

Hello

I know you said you've checked the switches and they may be fine, but did you ensure that the actual linkages to the switches were adjusted properly?

So, on my l35, there are leaf switches that are activated by the various linkages for shifting, brake and PTO. Yours has more switches.

On mine, the PTO switch linkage was full of crud and actually bent the switch leaf so far that it wouldn't work. (I ended up creating a new wiring harness and getting a new switch anyway in the restoration).

I've thought of 2 possibilities assuming the pedal switch is ok:
1) The engine solenoid circuit is not complete (like a seat switch for example) so that when you step on the hydro pedal, in gear, the circuit to maintain power to the engine solenoid is broken.

2) A switch on the gear (H M L N) is open - allowing the engine to start, but when put in gear, and pedal is stepped on the gear switch is still open causing the engine solenoid circuit to be open.

There are more switches but I hope the 2 scenarios I gave you help to troubleshoot. Let me know if this makes sense. These safety switches are wired in series meaning they ALL have to close the circuit to the engine solenoid to make the tractor go.

Example:
1) Driver in seat - Yes ( is there a seat tilt switch?)
2) PTO OFF - Yes
3) brake on - Yes
Allow engine start

1) Driver in seat - No
2) Gear selector switch in a gear - Yes
3) Pedal switch pressed - Yes
Stop engine

Also check all your fuses and fuse connections for continuity.

One last thought is to bypass one switch at a time (attempting to move forward - or backward), which is time consuming, but might be worth your time.



I found these on Summit Hydro, Do you think these are the same?

3/8″ NPT ISO 7241-B Quick Disconnect

3/8" NPT ISO 7241-B Quick Disconnect Hydraulic Coupler Set

Free Shipping 3/8" NPT ISO 7241-B Quick Disconnect Hydraulic Coupler Set

summit-hydraulics.com

 

[Russell King]

The Summit site has a printable chart of the couplers that you can use to identify what you have

The link to that is on this page

Quick Disconnect Couplers - Free Shipping Site Wide - Summit Hydraulics

We carry Flat Face Skid Steer, Ag, ISO-B, Wing-nut, and High Pressure Quick Disconnect couplers that will interchange with all major brands - FREE SHIPPING

summit-hydraulics.com

 

[jiggseob]

Thanks Nicksacco, a well thought-out reply.

I am almost at the dammit-point of hay-wiring around the problem, wiring directly from the switched 30-amp fuse in front of the radiator to the fuel solenoid, this bypassing all of engine-shut-down safety switches. The WSM manual mentions two solenoid coils within the fuel shutoff, one that "pulls open" and the other that "holds open". My testing of the other properly working tractor finds that both are energized all the time. Hmm.

I will try (again) to bypass the safety switches by "jumpering" across them. Much easier now that I have removed the seat panel to get to the top of the transmission.

I did remove (both male and female) failed couplers, took them to the agricultural industrial hydraulic supplier, they had about 30 different sizes/styes of couplers, including the ones I needed, for only $22 per. A block away, the Kubota dealer price is $55.

 

[jiggseob]

Hit the dammit point today. Hay wired around my safety switch issue.

I recall using an Allis Chalmers model U for chores around the farm. It started with a big crank in a hole under the radiator. If one was stupid enough to start it in-gear, the next-of-kin would call an undertaker, no one even thought of calling a lawyer. That was several decades ago, things are different now.

I started by removing and examining the fuel turn-on solenoid. The weird part is the two separately connected coils, one which pulls the plunger, and the other that holds the plunger once its pulled. Inside the solenoid itself is a switch, which disconnects the pull coil when the plunger hits full travel. The pull coil draws about 9 amps, the hold coil draws about 0.75 amps. All the test-lighting that I've done, both the pull coil and hold coil have power to them at the same time. When power is applied to both coils at the same time, the pull-coil moves the plunger to full travel, the plunger moves a switch inside the solenoid to disconnect the pull coil, and the hold coil holds the plunger in the pulled position, the amperage is 9 amps for a fraction of a second, then 0.75 amps until disconnected. If only the pull-coil is energized, the plunger pulls, hits the disconnect, releases, then reconnects and pulls, hits the disconnect, releases, and on and on like a buzzing solenoid diaphragm fuel pump, and the amperage is about 6 amps but jumping up and down. If only the hold coil is energized, the plunger does not move nothing happens but it does draw 0.75 amps. So connecting both coils at the same time will work, and applying power to both coils for "run" seems to be the way that Kubota does it. I just don't understand why they harness two wires to the solenoid.

So to wire around it, I started with a stock item from my wiring bin, an 8-foot piece of 12ga wire with an ATO fuse (15 amp) already in it, 6 inches from one end. The fuse end I put a ring terminal, which piggy-backed under the key-switched screw terminal on the back of the ignition-key switch. Then ran that wire forard to the fuel solenoid area. I did not want to "hack" the Kubota harness, so I wanted to scrounge a connector that would plug into the fuel turn-on solenoid. I went out to the car boneyard, in search of a two-conductor plug that would plug into the fuel turn-on solenoid. The MAP transducer of a 1991 chev sprint provided the plug that fits the Kubota fuel solenoid. GM-Delphi is a spin-off of Nippondenso, so not a surprise that connectors are the same. I spade-connected that connector plug to my fused wire from the ignition key switch. The complete, un-cut un-modified un-working Kubota fuel turn-on solenoid harness and connector is tied off along the tachometer signal harness, in case some subsequent owner who is smarter and more determined than me wants to figure it out.

So now the tractor moves just fine. Took it back out to the side-yard to couple into the loader. Hooked up the new female hose couplers to the valve block, and hit the lever to move the arms to line up the coupling pins, and I got a shower in oil. Turns out there are three leaking spewing hoses on the boom lift circuit. Thats what you get from hoses that have sat in the sun and weather for decades.

Here is a picture of those failed female hose couplers from the boom lift circuit. I have no idea what causes a failure like this, but those poppets are supposed to be retained by snap rings, which are missing... possibly in pieces floating around in the circuit somewhere.

Who knows what failure(s) I will find next....

 

[Nicksacco]

Ah restorations!
Always challenging.

Well, I'm glad you got the tractor moving albeit with some Chevy parts! A Kubovy.

On my L35, the fuel is always on. There is a timer circuit such that when the key switch is turned off, power is supplied to the fuel solenoid for a period of about 10 seconds. That solenoid moves the fuel lever on the injection pump to the "OFF" position stopping the engine. After 10 seconds, the timer turns off the power to the solenoid else the battery would continue to be drained.

Previous owners had so badly dismembered the wiring and such, I gave up and just made a new harness.

On your machine, it seems that the solenoid is energized while the engine is running. And there are actually 2 circuits going to the solenoid. Not seeing the wiring diagram I wondered if somehow we were chasing the wrong gremlin.

Anyway, best of luck!

 

[PaulL]

Seems to me that the HST switch must be working. Because the tractor is running, you press the HST, and the HST switch notices you've pressed it and cuts the engine.

The problem is that the OPC (the brain of the operation) will be saying "when the HST switch is triggered, check that there's someone in the seat, if there's not, cut the engine". So, my remote diagnosis says the problem is the seat switch, not the HST switch.

You could work around it by either jumping the HST switch so that the OPC doesn't know you're pressing the HST pedal. Then it won't cut the engine.

You could likely diagnose it by putting a voltmeter/measure resistance across the seat switch. You need to see how it behaves - is it closed when someone sits in the seat (someone being a 40lb bag of something) or is it closed when no-one is in the seat? Can you see it changing from in the seat to not in the seat? Can you measure power through it and see if it's working? It really has to be the seat switch, or otherwise the OPC itself broken.

Worst case, bypass the seat switch. But you have to bypass it right - you either need to disconnect it (leave it open), or you need to bridge it (make it permanently closed).

 

[jiggseob]

Thanks for the reply and thinking through PaulL, the seat switch is where I started. Unplugged it. Jumpered it. Swapped it with seat switch from other working tractor. Nothing.

The HST neutral switch similar. Unplugged, jumpered, swapped with switch from working tractor. Nothing.

I put several days - albeit "retiree" days - into finding this wiring fault. I do not like to mess with "stock", in general Kubota builds stuff well, and I really tried to repair back to what Kubota built. It really only took a couple hours to haywire it, and an hour of that was figuring out how the fuel-on solenoid functions. At any rate, I've gone around it, and left it all intact in case someone else wants to figure it out.

To town today to have three holy hoses re-made. The hoses connect with JIC fittings, and adapters are used to transition from the JIC of the hose connection to the 3/8npt of the cylinder ports. The stock hoses use 90 degree JIC fittings to connect to the npt-JIC adapter at the "far" end of a cylinder. When having a hose crimped up, a straight JIC crimp-on fitting is like $5, a 90 degree JIC crimp on fitting is like $20. So rather than telling the hose guy to put together exact duplicate of the holey hose, I request a straight JIC connection on the hose, and a 90 degree elbow npt-JIC adapter fitting. Saves $10 net per hose.

Hopefullly this is my last oil shower for a while.

 

[jonsstihl]

not sure if the seat switch is normally open or normally closed but I would suspect a defect in the seat switch wiring. perhaps the wires got pinched somewhere.

 

[jiggseob]

Done. L3130 tractor all together, all functions working. I've lost track of money, I think its some $2800 canadian pesos.

Main bearings, shells and main-bearing-1 bushing, two-thou oil clearance on assembly.
Rod bearing shells, two-thou of oil clearance on assembly
Thrust bearing segments.
Crank grinding service.
Front main seal sleeve.
Connecting rods with caps and bolts, ordered one, got set of three so two spares (?)
Full overhaul gasket set.
Clutch disc.
Fuel injection pump service at injection shop.
Two tie-rod assemblies, outers were OK but jobber assembles were half price of dealer inners.
Bucket tilt cylinder repair, should have replaced rather than repair.
Six hoses on the loader.
Two quick-coupler male-female sets on the loader.
One front tire.
Recovered seat.

From a tight-seized engine in a tractor that had sat neglected in a bush for at least 15 years, to a running working tractor. Five months almost to the day from dragging into the shop to driving out. Travelling to Perth WA and seeding crop and my duties as a retiree somewhat pushed out the elapsed time.

The toughest problem was a wiring-safety-switch issue that shut off fuel to the engine when the HST toe-and-heel rocker pedal is pressed off of neutral. Beat my head against that tractor for way too long trying to figure it out, finally just wired directly from the key-on terminal of key switch to fuel solenoid. Now it is easier to stand on the ground on the right side of the tractor, operate the loader controls, and operate the HST pedal with my hand and run myself over and do myself serious bodily harm. Almost as hazardous as standing on the ground and operating the hand-clutch on a John Deere model D.

Now I have two working Kubota tractors, a mid-80s vintage B6200 HST with Allied loader thats a bit tired, and the L3130 with LA723 loader. There will be management pressure to thin-down the herd. Not sure which to keep for my small 1.5 acre property....

 

[whitetiger]

both the pull coil and hold coil have power to them at the same time. When power is applied to both coils at the same time, the pull-coil moves the plunger to full travel, the plunger moves a switch inside the solenoid to disconnect the pull coil,

The Pull circuit should only be powered when the starter is engaged, the current is supplied to the shut-off from the started solenoid.

 

[Nicksacco]

Goodluck @jiggseob !

Overall I think it paints a good picture for you.

You and management have to work out the remainder - I'm stepping away slowly....

 

[jiggseob]

The Pull circuit should only be powered when the starter is engaged, the current is supplied to the shut-off from the started solenoid.

On this tractor, and on the newer series L3540, both the pull circuit and the hold circuit are energized at the same time. In all of the diagnosing and testing comparing the operation of both tractors, both the pull and hold circuits were energized at the same time. On the properly working L3540, and on this L3130, I did not find a circumstance where only the hold circuit or only the pull circuit was energized.

My brother, the owner of the L3540, was somewhat skeptical of me swapping parts back and forth to try and diagnose the problem with the L3130. After swapping fuel-on solenoid, HST pedal switch, seat switch, and clutch switch and PTO switch and cruise switch between tractors, I still hadn't fudged-up the L3540, so I gave up and did the wire-around.

After doing the wire-around, just to check how things were working, I pulled the fuse and connected my DMM in place of the fuse to measure Amps. For a fraction of a second on key-on, it pulled 9.+ amps, but not enough to fry the 10-amp fast-blow fuse built into the DMM. After initial power-on draw of 9+ amps, the current stabilized at 0.75 amps. So even though it would make sense to de-energize the pull-on circuit, the fuel-on solenoid itself de-energizes the pull on coil internally.

Dreaming about it for the past few days, I'm pretty sure theres a short-to-ground or short across the pair of wires somewhere in the harnessing to the seat switch on my L3130.

Put it to work and see what happens.