Broken tractor HELP

[smwwoody]

Well I broke my Kobota today.  I lost hyd. power to the bucket and it was makeing a loud grinding noise.

I tore it down and it was what I thought it was.  The coupoler that hooks the pump to the end of the crank shaft was striped out.  the big problem is that the splines on the end of the crank shaft are also stripped.  Any good ideas for fixing this without replaceing the $2000.00 crank shaft?

This tractor with forks on it is what I use for moveing logs and lumber at the mill so I am at a stand still with out it :( :( :( :(

[smwwoody]

here is a quick drawing of what I am working with

[Paul_H]

smwwoody,
I'm sorry to hear about your breakdown.Is there any way you can get a good picture,and post it? Also wondering if you have a 2speed pto,and could mount it to the back as a temporary measure.

Sounds like the crank is going to have to come out eventually,and go to a machinist.

[Bro. Noble]

I wouldn't have thought the pump would have pulled hard enough to strip splines.

Old Farmall tractors used a collar with pins through the shaft and collar to connect the pump.  You pulled the pins and slid the collar back to disconnect the pump in the winter so the tractor would turn over to start easier.  you might try a temporary fix of using a collar like this with pins if possible or even set screws.  Even a piece of heavy duty hose and some hose clamps might make a temporary fix.  I think before spending a that kind of money I would figure out someway to attach both shafts to a collar even if I had to spot weld it.  It would require low hydrogen rod on those high carbon shafts.  I would only do that as a last resort.

Noble

[Bro. Noble]

Woody,

I've been thinking more about your problem.  Before you hook the pump back up reguardless of how you do it,  I'd check out the pump.  Something may have come apart and locked up the pump resulting in the stripped splines.

If this is a weak point with the tractor,  they may have some kind of repair kit arrangement.  

You can probably take the pump shaft to a machine shop easy enough to have whatever you want done to it.  you might be able to get a sleeve with larger splines (or some other connector ) that would slide over your damaged splines and weld in place.

Noble

[Paul_H]

Noble,
It makes sense what you metioned about checking the pump.I wonder too,if the mount bolts were loose for awhile.

Do you mean making up a collar to sweat on to the end of the crank?That should work.

[Bro. Noble]

Paul,

Yes,  anyway he can secure a collar over the damaged shaft should work.  the pump end of the collar shouldn't be a problem as the collar and pump could be taken to a machine shop to be matched in the easiest manner.

Noble

[Tom]

I'll bet that the crank can be threaded.  If so, repairs are numerous.

You could also put the tractor on a trailer, take it and the pump to a machine shop and say "I want this attached to that".  Probably wouldn't be too much money if the sheet metal were removed first.

[Paul_H]

I just had a look at my little Kubota.It's a little 12 hp B4200,but maybe the principle is the same.It has a splined collar that fits over the spline in the crank.The collar is secured with 3 bolts,and is splined as well on the outside diameter.If you have a similar setup,it should be fairly easy to repair through a machine shop.The picture was taken sideways.





The tractor is Carla's.We bought it used for her birthday a couple of years ago.

[Gordon]

Another idea is maybe some sort of lovejoy coupling. Metal outer coupling and a hard rubber inside to help absorb the shock of start up. This way the rubber coupling will go bad the next time. Alot cheaper and alot less money as well.

Good luck with it.
Gordon

[ElectricAl]

Woody,

We had the same problem with a Ford 801 industrial. The pump is connected to the crank by a shaft that actually went through a hole in the axle pivot.
The coupler had gotten loose and stripped the splines.
Our local fix "anything" shop was able to cut 3 new splines in the shaft and hub, then reassemble with something similar to a woodriff key.

We were looking at a $1000 used crank plus labor. Which would have been more than the tractor was worth to me.
Cost around $280 for the 3 way spline.

Let us know how it goes.


ElectricAl

[smwwoody]

thanks for all of the help

I am going to try to cross drill it and pin it to get me by untill spring when I am planning on doing a major rebuild on the engine. at that time I will fix the crank right or replace it.  if this does not work I will have to use the main pump that is transmission driven to work the forks untill spring.  I checked out the flow and pressure rates on it ands it is real close to the same.  All this will take is some rerouting of hoses.

[johnjbc]

Had that problem once on an old case backhoe, only it was the spline in the pump that striped. I bought a new coupler and a tube of JP Weld Epoxy . Its still working after several years. When I checked the maintenance schedule it turns out that you are supposed to lube the splines every couple  
hundred hours. Most people don't do it. : : :
John

[Lenny]

Smwwoody
Are you sure the drive side is part of the crank?Most I`ve worked on were bolted to the harminic ballance.(cat,hyster.yale,toytota,clark.ford)ect.
 If you can drill it. I recomend using A spiral pin rather than A roll pin or bolt.They are very strong spring steel.
 Loctite Quick metal works well on damaged shafts.It expands as it cures to A press fit.
 If you resort to welding try not to get it too hot as this takes the temper out of the steel. could lead to bigger problems and
a bad oil seal.
  Whatever you try, Alighnment is A BIG factor