Who rebuilds HSTs?

CJN8

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B2650HSD, LA534 FEL, Gearmore Box Blade, Bush Hog, Cimmeron Rake
Nov 16, 2013
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Just curious who rebuilds these? Anyone? I have a B7200 HSTD that I may what addressed in the future...Kubota wants $2K plus for a new unit.

Thanks,
Nate
 

Eric McCarthy

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I can't think of anyone who rebuild them. The HST is supposed to be "indestructable" but like everything else they can break down and need rebuilding or a small fortune replacing. This is one of those times I think a gear trumps an HST. I'd rather replace a 200 dollar clutch then a 2,000 pump.
 

hodge

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It wouldn't be too hard to hit $2000 if you had substantial damage or wear in a manual transmission.
I think that the dealership will probably be your most viable avenue, for one glaring reason- not many people need them rebuilt. I don't recall seeing many posts here, or on other tractor forums, where people are needing hydrostatic transmissions rebuilt.
Another thought- it is hard to find a shop that rebuilds manuals. All of the threads here at OTT are about individuals rebuilding their own. So, manual or hydro, when they go, the dealership is probably going to have the folks who know them best. And, I bet the techs are more familiar and trained with the hydros than they are manuals.
 

kjjehnzen

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B1750 HSD
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The problem is finding parts at a competitive price, 'cost of parts to rebuild' + 'cost labor to rebuild' = 'rebuilt HST' at same cost of 'new HST'. The correct equation to use is : 'preventative maintenance' = 'many years of service'
 

Profnohair

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L1500, 42" bh, box blade, G6200HST, Mahindra 450 with BH, FEL, etc.
I have a G6200HST that I happened upon the HST service manual on the net. They are not manufactured (at least mine wasn't) by Kubota. Mine was made by a well known national company that has a name that slips my mind at the moment. I am at work and can get it tonight though. From the looks of it, all it is a bunch of o-rings and valves that guide the fluid in the correct direction if I remember correctly. Maybe you can find your manual and rebuild it yourself.


Revision: the HST is an Eaton brand in the G6200
 
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aeblank

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Jun 19, 2013
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Cadillac, MI
Pump is probably eaton or parker or rexroth or similar. But what needs rebuilding? The pump, or everything else? I'd think there is a LOT in an "HST transmission".

Sent from my DROID RAZR using Tapatalk
 

CJN8

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B2650HSD, LA534 FEL, Gearmore Box Blade, Bush Hog, Cimmeron Rake
Nov 16, 2013
122
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San Diego, CA
Good discussion, I agree that preventative maintenance is the best medicine. I just bought this tractor from a fellow on CL for $2800 which included a FEL and 4' rollover box blade. I have been going through it a fixing what needs fixing. I have cleaned it up, fixed hydraulic leaks, added a new seat, new front grill, new engine stop cable, changed fluids/filters, basically giving it some much needed attention. This old girl has done some great work; I have used it every weekend since I bought it in November. One thing that I will eventually need to sort out is the tractor loses push power a bit once it warms up, not to the point that I can’t still use it but it is noticeable. I have not done the trouble shooting on the HST unit so at this point i am just guessing worst case. I know it could be the check valves, pump, etc, etc. I guess until I pressure test I wont know.
 

Kubota Newbie

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M4500, New Idea Cut-Ditioner, JD 14T Baler, IH "Plow Chief" plows, Oliver Rake
Dec 28, 2010
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Mount Vernon, Ohio
I've done a couple small HST units, one Cub Cadet and one Simplicity/Allis-Chalmers. To be honest there's not much to them, a charge pump (regular gear pump), drive and driven cylinder pump units (usually carbon copies of one another), a swash plate that controls oil feed on the drive pump and a fixed ramp plate against which the driven pump pistons run. That's about it. Much simpler than a shuttle/automatic planetary type tranny. The little Sundstrand type HST units in the garden type tractors are just scaled down versions of the ones they used in the combines & etc.
The wear parts are the charge pump gears/housing, swash plate, drive plate and pistons/piston feet. Usually because of cavitation due to being towed, low oil, or very dirty oil.
 
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Kubota Newbie

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M4500, New Idea Cut-Ditioner, JD 14T Baler, IH "Plow Chief" plows, Oliver Rake
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Mount Vernon, Ohio
BTW, what's it doing??? Problems usually lie in the charge pump system, or with a plugged filter, occasionally a charge pump pressure valve.
 

Eric McCarthy

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Have you drained and replaced the hydro fluid and clean the suction screen too? Sounds like its still working just thinned out fluid.
 

CJN8

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B2650HSD, LA534 FEL, Gearmore Box Blade, Bush Hog, Cimmeron Rake
Nov 16, 2013
122
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San Diego, CA
I did change the fluids. I cleaned both screens, the hydro screen was pretty nasty, i cleaned the screen but even when the screen was cleaned you could not see through the wire mesh very easily. If i held it up to the light it made it easier to see. I changed the filter too. I used Super Tech fluid from wally word, said on the carton it was UDT compatible.

The issue I am having is that after it is warm and i put it in high to transport it loses steam while going up slight inclines. I roll off the speed changer but it will still stall out and the hydro will whine at me.
 

Kubota Newbie

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M4500, New Idea Cut-Ditioner, JD 14T Baler, IH "Plow Chief" plows, Oliver Rake
Dec 28, 2010
531
81
28
Mount Vernon, Ohio
Further explanation required:
The engine "stalls out"?
or
The engine continues to rev and the tractor "stalls out" or stops moving?
 

Kubota Newbie

Active member

Equipment
M4500, New Idea Cut-Ditioner, JD 14T Baler, IH "Plow Chief" plows, Oliver Rake
Dec 28, 2010
531
81
28
Mount Vernon, Ohio
I would suspect an oil delivery issue to the charge pump, or a charge pump pressure issue first. The screen and filter need to be really clean.
BTW, you can use any non-foaming hydraulic oil supplement (viscosity improver) and it won't hurt anything. If it is a worn charge pump the thicker oil will usually help on an old machine. I like to add some soluble moly supplement to my hydro units.
I have one cub cadet unit that is easily 40 years old and gets used all the time. Runs like a top, use generic replacement for IH Hy-Tran fluid and a bottle of Shaeffer's Moly E.P. treatment. Use Lucas Hyd oil stabilizer in my M4500.
 
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CJN8

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B2650HSD, LA534 FEL, Gearmore Box Blade, Bush Hog, Cimmeron Rake
Nov 16, 2013
122
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San Diego, CA
I cut open the old filter yesterday and it was clean inside. I think I will pull the front cooler off and look to see if there is any garbage in it. I like the idea of a viscosity improver. I live in San Diego so thicker fluid will not be an issue. BTW it's 80 degrees this weekend. Thanks for all the ideas.
 

cb750k8

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B7200HST D 4X4
Aug 23, 2013
101
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Dublin, Ireland
Hi
There is quite a good Manual available on the HST if you feel you want to "do it yourself". Typical page attached. Dont recall where I got this manual. It may have been on kubotabooks.com.
I have not taken the HST apart (mine works OK) but it looks easy enough if you are reasonably equipped with tools.
Thing to do is to test it and check against the recommended pressures before you think of taking it apart or spending $2,000
If Kubota don't make these HST's I would be interested in finding out the manufacturer. These units may be used in other machines and there may be other sources (other than Kubota) for parts.
Cheers
 

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CJN8

New member

Equipment
B2650HSD, LA534 FEL, Gearmore Box Blade, Bush Hog, Cimmeron Rake
Nov 16, 2013
122
0
0
San Diego, CA
If I am not mistaken kubota makes their own hydros. The charge pump might be a standard brand but the hst design is their own.

On the viscosity improver, how much do you add? Will this harm seals?