Reviving a G1900

[Hugo Habicht]

Hello,

as some may have read already in another thread I rescued a G1900 lawn tractor that, I believe, would otherwise have ended up in a scrap yard. The last few years it had been neglected and is in very poor condition. But short wiring the starter I could get it running and it started first turn of the crank shaft. It cut the grass and since I needed a better lawnmower I thought it is worth repairing it.

Since it has not seen a grease gun for a while a lot of joints and bearings are badly worn out, the worst being one of the rear steering knuckles where you can move the wheel more than 1/2". Bonnet (hood) dangling of one bolt, air filter hanging loosely of its hoses, steering wheel 360 degree (!) play. As you can see, a lot of tlc required.

North Idaho Wolfman, in another thread, had concerns about buying one of those with 3000 hours on the meter which I believe are based on lots of experience and should be listened to. Mine had 6045 hours when I got it. Yes, I hear you, scrap yard a.s.o., but since the engine is running fine and the hydraulic transmission seems to be reliable I decided to take the risk and give this little tractor another lease of life.

I would like to describe the various repairs and maintenance in this thread in the hope it may help others and although it may be seen as a project thread I think it should be here because it describes Kubota repairs. If it should rather be in the Project Forum I would ask the moderators to move it.

And yes, I am well aware that what I am doing may not make a lot of economical sense

Kind regards,
Hugo

 

[Hugo Habicht]

Combination box and coolant hoses

The first thing was fixing the electrics. The starter motor would not turn. The solenoid is driven by the "combination box" which adds some safety features and also controls the preglow light and the engine shutoff solenoid.

The switches going into the box are PTO, brake and seat. I checked all wire harness connections and all switches and found the brake switch to be faulty. So I shorted this and it still would not start. Signal on box connector was clearly present. So the combination box itself must be faulty, I will knit my own electronics, and in the mean time I wired the starter directly.

Tightening one of the steering ball joint nuts reduced the steering play from 360 to 90 degrees. The rest seems to be in the front axle pivot, a job for another day.

So I could drive it on a trailer and bring it home and wanted to try it out. Oil levels are all fine and no leaks visible. It cut very low but I kept going and after just 10 minutes there was water on the cutting deck and after I stopped all the water ran out. Water pipe burst at the bottom of the radiator.

This ended my first attempt and I ordered all hoses from the Kubota dealer. I was considering using generic ones but the price is very good and the burst elbow for example has two slightly different diameters.

The numbers are:
16861-72850 radiator to connection
15881-72870 connection to water pump
16851-73350 return
16871-72940 thermostat to radiator S/N >= 11320, 16861-72940 otherwise

 

[Hugo Habicht]

Fan belt replacement

The fan belt was top on the long prioritised to-do list:



Lugbolt here in the forum kindly pointed me in the right direction how to change it after I failed initially.

First take the mower deck off.

Then loosen the bolts on the dynamo, top and bottom. Just loosen them, don't take them off. Push the dynamo fully towards the engine.



Now take off the three bolts connecting the driveshaft flange onto the flywheel. Accessible from below. I am not sure if that is required but I only turned it in normal direction of rotation when turning the crank shaft to get at the bolts.



The flange can now be pulled backwards and the drive shaft moved aside to create a gap to get the fan belt through.



I used an AVX 10x875 fan belt. As you can see the old one was slightly worn already. Maybe I could have got another few hours out of it.



Put fan belt over the fan, over the dynamo pulley, the flywheel and over the fan pulley. Then slide the dynamo and tighten the bolt so that you can push in the belt 10mm (0.4 in.) when applying 10kg (22 lbs.) force in the middle of the belt between the flywheel and dynamo.



Now attach the driveshaft flange to the flywheel and tighten the bolts. I used low strength Loctite thread locker for those.

Attach mower deck.

Done.

 

[Hugo Habicht]

Second test

Replaced the bottom hose and filled everything with water initially. The anti freeze and corrosion protection has to wait until I get the other hoses. I want to flush the system a few times because I do not know what anti freeze (if any) had been used. Mixing the wrong ones can lead to jelly, which is not really what I want inside the engine.

Greased all grease nipples, tidied up some of the cables.

Could not adjust the deck properly, it is running on the anti-scalp rollers now, but I was ancious to use the machine as intented by its manufacturer.

Started fine and I spent 2 hours cutting everything. Even grass over 60cm (2 feet) tall with the deck lifted and very slow forward movement. To distribute the cuttings I went over everything at full speed and was delighted. I do not think there are many lawnmowers where you can feel the air stream in your face

There are a lot of brown cuttings now that were left from my old grass cutter that have been chopped up now. Once I cut more often with the Kubota this should improve.

 

[lmichael]

6000 hours and that much neglect a testament to how stout that little diesel is. Keep it up!

 

[Hugo Habicht]

6000 hours and that much neglect a testament to how stout that little diesel is. Keep it up!

Yes, you are 100% right, it is a stout little tractor.
Will definitely keep going.

Problems I identified so far:
- steering knuckles rear wheels excessive play
- wheel bearings front excessive play
- front axle pivot excessive play
- front axle grease nipple broken off
- steering ball joints some play
- steering ball joints rubber gaiters perished
- PTO front shaft bearings not running properly, worn
- oil pressure switch faulty (wiring and light good)
- engine oil dip stick not tight enough, possibly wrong type
- temperature too low (thermostat or sensor faulty)
- reverse speed too slow (adjustment, I think)
- dash board key switch mount broken
- rear reflectors cracked
- front light cover cracked
- lights not working
- starter and shutoff not working reliably (combination box)
- panels corrosion
- frame minor corrosion
- floor panel crudely cut out (for cabin mounted at some stage)
- bonnet (hood) holes drilled (for cabin)
- cutting deck reinforcement bar cracked
- cutting deck front mount too long, pin holes worn
- blades in bad shape, sharpened them but need new ones
- front left wheel losing air (had tyre off already, cleaned rim, improved matters but not fixed)
- battery bracket missing
- seat cover torn
- steering wheel center cover missing
- one rubber buffer for bonnet (hood) missing on radiator
- full service required (all oils, filters changed), will do that next

In total a bit of work, a good few new bearings, shaft seals, welding, corrosion removal and painting. Financially I think it should be acceptable, want to repair parts if possible instead of buying new. Although some Kubota parts are very reasonably priced (also considering the age of the tractor) I found some parts that I rather wish I will not have to buy

 

[lmichael]

Yeah, I bet parts are on the expensive side there. While not cheap here, not too bad. Good luck on saving that old little beastie.

 

[arml]

good job!