Broken HST/ No Reverse= HUGE $ to Fix!

KubotainNH · Mar 19, 2013

Dick, if you make a new thread for this please post the link here. These are fun to watch. Thx.

Grandad4 · Mar 19, 2013

Dick, I was speculating who might adopt an orphan like this and your name came immediately to mind. Glad she's in good hands. That indeed looks like one heckuva combination FEL and BH subframe. Hope you'll keep everyone apprised of your progress.

Grandad4

rbargeron · Mar 19, 2013

hey Mike - great PS addition - my L345 could use an assist like that - it has a hydraulic motor at the bottom of the steering column but it's pretty anemic.
I'll probably post the L48 fix right here. There are other projects ahead of it, but the schedule gets shuffled sometimes when something cool like this comes along.

Hank - bet it's closer to Spring in Piedmont than it is here - got more heavy wet snow today.

dfkrug · Mar 20, 2013

rbargeron said:
OK, I'm the culprit - I adopted the ailing L48 mostly for the technical
challenge, hope to learn something and have a story to tell sometime.

Great that you bought CF's L48, Dick!

If I was on the E Coast, I mighta been a competitor. I am envious.

When I rebuilt my B21 (see Dave's link at post #31 above), I was happy to
find that Kubota sold HST subassemblies, like the HST pump or motor, at
fairly reasonable prices. Turned out I did buy an all-new charge pump, but
my HST was otherwise in good shape.

I am curious how the L48 controls the swash plate angle. Is there no
mechanical connection between the pedals and the swash plate shaft?

rbargeron · Mar 20, 2013

Hi Dave - great that you are here - I'll be looking for peer review on whatever I try to do.

No, there is not a direct linkage from pedal to swash plate angle. The pedal linkage has a damper that prevents abrupt pressure shocks, and then more linkage to a scotch yoke-style spool valve actuator that regulates flow to another servo. The manual isn't crystal clear, but the servo is a cylindrical item with a helical slot in the side that moves to expose the desired flow area. Neutral may be at mid-travel - but I need to take it out of the housing to get a closer look. Looks like it comes out the bottom which means draining it - so I may try to inspect/eliminate the regulator valve first, while I can still test the result with real flow. Somebody who actually knows how it works would maybe chuckle at my description. My day job is busy right now so I'm not getting much play time.

SSweet9c1 · Mar 20, 2013

Following this thread!
Jonathan

dfkrug · Mar 20, 2013

rbargeron said:
No, there is not a direct linkage from pedal to swash plate angle.

A fun project, no doubt. I will be watching.

Since you have other tractors for lifting, you should not have a hard time
removing the FEL and FOPS. The mainframe will add an extra step, too, but after that,
it should be like most compact tractors.

And it is SO good that no one has taken it apart before you got your
hands on it.

dfkrug · Mar 20, 2013

rbargeron said:
No, there is not a direct linkage from pedal to swash plate angle.

A fun project, no doubt. I will be watching.

Since you have other tractors for lifting, you should not have a hard time
removing the FEL and FOPS. The mainframe will add an extra step, too, but after that,
it should be like most compact tractors.

And it is SO good that no one has taken it apart before you got your
hands on it.

Grandad4 · Mar 20, 2013

rbargeron said:
Hank - bet it's closer to Spring in Piedmont than it is here - got more heavy wet snow today.

The trees are convinced it should be Spring, but Ma Nature is still playing around with low - mid 30's temperatures each evening. If she ever gets around to shutting off the refrigeration, everything will green up quickly.