G1900 HST - No hydraulics

[cabbage]

Howdy,
I have a problem with my Kubota and I have come to this forum seeking wisdom. I have an old G1900 HST mower that has seen betters days.
Sadly last year mid-season it threw a rod through the side of the block (D722 engine). A new engine was well out of my price range and second hand ones are like hens teeth and priced accordingly. Anyway after some deliberation I pulled the old engine out and installed an old Ducati diesel twin instead. The Ducati should be slightly more powerful and I know its in good condition. I wont bore you with the details but it wasn't a straight swap as you might expect.
Anyway, I got the ducati engine all hooked up, and everything tack welded in position, in case I have to make minor adjustments. I run the engine and its all good except when I select drive, or try to lift the deck arms nothing happens. There is plenty of oil in it and the filter is fairly new. The drive to the HST is all good, I can see the HST input shaft spinning.
I think we can rule out an electrical problem as there isn't any electrics on it at the moment. I just have a battery charger providing power to the diesel lift pump. Does the HST need 12v DC to operate in some way? Its so long ago I stripped it down, I can't be sure but I can't see any electrical connections to the HST system that would stop it working as long as the engine was running.
Another possibility is that I towed it off the field where it threw the rod. Could I have damaged the transmission? If so what did I damage? With the wheels off the deck the differential appears to work fine, however if I turn both the wheels in the same direction, they turn fairly easily producing a small rattley noise from the transmission. Is there a sheer bolt inside I might have broken? (thats the sort of noise it makes) I am reluctant to take the transmission to bits without a manual, however I don't want to buy one only to discover the transmission is dead. Its not worth spending any more time or money on as it pretty worn generally.
Thanks in advance

 

[traildust]

Cabbage,
I feel your pain and sorrow. Your story is almost the same as mine was about seven years ago. Shelled an old and very strong Craftsman Garden Tractor. Repair was not feasible and the cost of a replacement engine was the same as another small tractor. Unfortunately I purchased a JD L120HST (lawn tractor). It was a waste of money with not even half the power of the Craftsman. After too much abuse to the JD, I ended up at the right place at the right time and purchased my Kubota five years ago.

For your HST issues, I am not familiar with the G1900. But I do have a strong hunch the HST not operating has nothing to do with electronics. Sadly I think something happened when it was towed.

On my JD L120 there is a lever on the back side just above the tow hitch. Normal operation calls for the lever to be pushed in. If the engine can not run and the tractor has to be pushed or towed the lever must be pulled out. Some how this disengages the mechanisms so the wheels can freely turn with out trying to back drive other things.

I have had to use that lever quite often as the thing isn't the most reliable machine I have owned.

Do you have such a lever on your Kubota?


Scott

 

[cabbage]

Hi Scott,
Thanks for your support. There is no lever or button on the HST as far as I can see. Even if there is one hidden somewhere I didn't use it before I towed it.
Cheers Cab

 

[traildust]

Hi Scott,
Thanks for your support. There is no lever or button on the HST as far as I can see. Even if there is one hidden somewhere I didn't use it before I towed it.
Cheers Cab

Cab,
I wish I could be of more help to you. Vic, one of the moderators will be back on line in a day or two. Kubotas are his living and hopefully he will have a lot more constructive advice than I can ever offer.


Good luck,
Scott

 

[dusty-t]

Hi Cabbage, I have no experience with Kubota lawn tractors but I do have a fair bit of experience with lawn tractors in general. You said you checked the oil level and the filter I am assuming you mean the oil level and filter on the hydrostatic transmission and not the engine. If I assume wrongly then check your level and filter on your transmission. Does your tractor only have one speed range or two, if it has two then it may be stuck between ranges. Check the mechanical linkage between the hydro pedal and the transmission for bent ,broken or binding pieces. If the noise you hear when you turn the rear wheels sounds like a large ratchet then it is probably normal. Sorry I can't be of more help. As Scott said stick around for a couple of days and maybe some of Orange experts will stick their nose in here. There are lots of people on here with a lot of tractor wisdom that they share freely. Good luck and keep us posted. Dusty

 

[handyman]

Cabbage got a question by any chance does that have a belt drive for the transmission and since you changed the engines the pulley is slipping or needs adjusting? Just a question Im not familiar with that particular model. Im sure someone will jump in and help get you going. handy

 

[Butch]

Hey Cabbage sorry to hear about your G1900. However, My neighbor has a G1800 that he has had forever and the 1800 and 1900 are like brothers.

So....I scoped out hid ride just a few minutes ago and there is no way to disengage the tramsmission from the drive axle to facilitate towing. As a matter of fact his WSM says that damage to the HSD is almost inevitable in the event of towing.

Also, his hydraulics are independent of the 12 volt electrical system. If the motor runs and you pedle down in forward or reverse the buggy will "boogie".

I am very interested in what the experts come up with on this site. Best of luck! Butch

 

[traildust]

I have to say I am very impressed with everybody stepping up to help Cabbage.
Thank you Dusty, Handy, Butch and last but not least, Vic for helping with experience that none of us have.

And for Cabbage, our new brother! We know the diagnosis isn't what the patient wants to here. However, if you decide on a tear down for HST repair then start a thread on it. You will not be alone as long as you post on here.

Scott

 

[cabbage]

Hi Guys, Thanks for the welcome and the advice!
Sadly it was the transmission oil level I checked and all the levers and pedals are ruled out as they are not connected! The mower is heavily stripped down, just a chassis engine and transmission. It's up on axle stands so that I could test the drive.
I'll start a tread if I strip it, I'd just like to be armed with a diagram first that I can take out to the workshop (I don't think my laptop would last long out there!).
Thanks to Dusty-t's help, the diagram at Colemanequip for the HST shows a pin (part number 360) that looks like the drive pin for the pump gear (part number 180). I wonder if this pin has sheared? It sounds like a mechanical failure when the wheels are rotated, as if a shear pin had gone. That said I might be being optimistic.
This must be a fairly common problem. I can't be the only one stupid enough to tow one of these machines:eek.
Thanks again - Cab.

 

[cabbage]

I forgot to say does anyone know if any special tools are required to strip the HST? I have a good selection of hammers

 

[traildust]

I forgot to say does anyone know if any special tools are required to strip the HST? I have a good selection of hammers

Don't forget this one....

Scott

 

[traildust]

I forgot to say does anyone know if any special tools are required to strip the HST? I have a good selection of hammers

Bump for cabbage


Scott

 

[cabbage]

Thanks Scott.
No one seems to know if special tools are needs which I guess is a negative, however on the positive side no one has said arrggg don't do it its impossible etc (apart from my dad). I have stripped and rebuilt manual gearboxes before that are still working and a couple of hydraulic pumps. However I have never stripped an HST which is a little worrying.
Its really handy to be forewarned before stripping a manual transmission otherwise there are lots of pitfalls such as- unseen springs launching a ball bearings across the workshop into either a drum of waste oil or the pit. As anyone who has stripped a manual box will tell you.
I will have a go at it at the weekend hopefully.
I'll let you know the results, unless a nervous breakdown prevents me.
Happy St. Patrick's Day -Cab

 

[traildust]

Thanks Scott.
No one seems to know if special tools are needs which I guess is a negative, however on the positive side no one has said arrggg don't do it its impossible etc (apart from my dad). I have stripped and rebuilt manual gearboxes before that are still working and a couple of hydraulic pumps. However I have never stripped an HST which is a little worrying.
Its really handy to be forewarned before stripping a manual transmission otherwise there are lots of pitfalls such as- unseen springs launching a ball bearings across the workshop into either a drum of waste oil or the pit. As anyone who has stripped a manual box will tell you.
I will have a go at it at the weekend hopefully.
I'll let you know the results, unless a nervous breakdown prevents me.
Happy St. Patrick's Day -Cab

Cabbage, don't give up on the forum response. The only reason no one has responded yet is because the people that do know how haven't seen it yet.
Chances are real good with the weekend over that Vic will be on line soon and I'm sure he will help.
I'm glad to hear you are going to tackle this thing and I think you will be ok. You do have experience with the manual ones and that should be a really good foundation.
Besides, when people say don't tear into that thing! Doesn't that make you want to try even that much more? Of course it does and you will succeed!

Keep us up to date,
Scott

 

[dusty-t]

Cabbage, found some parts illustrations http://www.colemanequip.com/ModelParts.asp?modelID=291&pc=128385#partdiagrams Hope it helps a little. Dusty