B6100HST Hydrostat problems

[dem45133]

Good day everyone...

Ok, I need to pick your collective brains.

We recently bought a B6100HST 4x4 on eBay and while I am working 1500 miles from home, I did have my wife eyeball it and I at least listened to it over the phone. I also had her take more pictures. 1200 hours on the meter (working) if that actually means anything when its 20+ years old. It was sold as "4x4 not engaging" and we bought it accordingly (I think!... seems even salvage price are high on these... but then it is a real tractor and not some piece of stamped sheet metal with an engine glued to it). Anyway, I know, its like cards... one lays down his money and takes his chances. Engine runs well and sounds good. 48" deck is fully serviceable and I also bought a second parts deck just because all the mechanicals were good and I had no idea what I might need.

So the seller delivered it the 170 miles to the house. I then had a local repair outfit pick it up to go through it and service everything and get it ready for my wife to mow with this summer. I asked them to look at it with the same eyes as if it was their wife or mother that was going to have to run it all summer with them not there...

He did that... including all fluids and filter changes. Someone in the past had removed and bypassed the oil cooler... so we built up a generic replacement of the appropriate sizing and flow rates. Other than that, we know nothing on its history.

Upon test mowing.... the HST started acting up.

Here's what I'm told...

1) 4x4 not engaging ... while we knew that... maybe its related.

When cold (i.e trans not up to operating temp)

2) operates in 2wd just fine for about 15 minutes in low range and then starts slipping or at least not operating gradually to point it will not move... (as the hydra fluid warms up???) Not drawing power from the engine... not laboring it at all so I'm told... also no squeal like drawing air would do.

3) operates in 2wd fine in high range for about 5 minutes... then the same just slows up to nothing. Also no squeal like drawing air would do.


The last I heard they are checking some screens and other easily accessible items.

I do not have a shop manual for it yet... I've been looking, and yes I can get brand new ones...I had hoped to find a used one... no luck so far... but I may have to bite the bullet and lay out the $150-175 for the new one. As such, I can not trace out the system design and relate it to the above.

So far:
new fluids and filters
screens cleaned... reportedly crappy but no broken steel

I don't know if they are equipped to do pressure tests or not... one guy was a mechanic for our local Kubota dealer for 15 years... so I hope he knows something... the other was with a mower shop also for 10 years or so. Both have now opened their own shops.

Last I knew they were going to see about pressure tests... but haven't heard back yet. Tracing this while working 1500 miles away with all my tools and shop at home... is getting aggravating. Its very very rare that another man's tools touch my stuff (for the past 45 years and I have a full shop)... but I'm in between a rock and a hard spot right now.

Any ideas I can pass on to these guys... besides taking it to our local Kubota dealer? Thanks in advanced for your thoughts.

Dave Mikkelson
Hillsboro Ohio (currently working in New Mexico)

 

[traildust]

Dave,

Sounds like those two fella's are on the right track. I hope they don't look at your tractor as the gravy train though.

 

[B7100]

I have a WSM for your tractor as a PDF which is 23Mb so may be too big to send to your mailbox..I could make a new file and just send the pages pertaining to the HST if that is any help.if so Pm me with your addy.
Dave

 

[dem45133]

Yea... I've thought of the bottomless money pit thing too... believe me!

So far:
$2550 to buy it, but sheet metal straight and paint/decals are decent... late model seat. Finish restorer would likely make it look like a new one. Like new tires (Ag)... 48"deck solid and mechanically sound, but could stand some new rollers. (nothing was mentioned... although the seller likely may not have known about the missing trans cooler. Now that I know it, I'm surprised I missed it in the pictures as it didn't have the grill in place... my wife would not have spotted it as abnormal and I wasn't there. Bit worried about that... especially now. It appears its primary work was mowing... not ground traction work...but who knows?)

$170 to deliver to the house

$225 for the extra deck on eBay (including shipping from CT, just the gear set is worth more than that! Deck housing got bent when the tractor it was on got hit by a car.. mechanical parts were all in working order)

$30 for a like new new grille on Ebay

$4 to 500 (he says) estimated so for for parts and labor (new generic trans cooler, all filters and fluids, flush and change coolant, two glow plugs, and I also had him add a manual trans temp, oil pressure, and coolant temp gauges... I'm a big believer in gauging) as well as inspect, sharpen and service the deck including changing out the gear lube in the gearbox.

$3350-$3450 in it so far... now the tranny issue... at 1200 hrs the injector pump should be fine for quite a while... but who really knows how many hours is really on it?

I'm going home for my vacation in a couple weeks... depending on what they come up with I may have to open it up and rebuild that hydro myself. Been into other hydro systems before... not afraid of it... just afraid of parts costs and availability.

I really do need that shop manual... exploded views tell me everything!

Assuming the pump is good or can be rebuilt and the side plate machined level again... (I have a mill) whats the most likely reason for the 4x4 not to engage? I assume is a pressure engaged wet clutch pack?

If that HST was run hot (no cooler)... what should I be expecting?

But its equivalent to a 14-15K or maybe an 18k new tractor... which will never happen.

Thanks and keep it coming....
Dave

 

[dem45133]

Hello B7100

We were writing simultaneously.... A resounding yes for the pdf. I'll PM you.

Thank you so much!

Maybe I'll have so knowledge or aid I can do for you someday...

Dave

 

[dusty-t]

Hi Dem. I think your b6100 isn't too much different than my B7200. Single plate dry clutch - propeller shaft to hydrostatic transmission - the 4x4 shaft comes out of the hydrostatic transmission to the front axle. The tractor has a hydrostatic pump and motor in the transmission and a hydraulic pump on the engine using a common reservoir for both. Hydraulic and hydrostat systems are totally seperate systems other than using a common reservoir. You may already know all this. The money you have invested does not seem to be high. So it is worth putting a bit more into it. The 4x4 not working?. The front axle has a gear case on each wheel, if a gear has busted in one or the other you get no 4x4. Check this out http://www.colemanequip.com/Kubota-B6100-4WD-Hydrostat-HST-Tractors-Parts/? Not much help but doing what we can. Good luck and keep us posted. Dusty

 

[dem45133]

Thanks Dusty

That would do it, wouldn't it? It would just turn through the diff. Will check it out...

Supposedly no abnormal noises...

Dave

 

[Bulldog]

Check this out http://www.colemanequip.com/Kubota-B6100-4WD-Hydrostat-HST-Tractors-Parts/? Not much help but doing what we can. Good luck and keep us posted. Dusty

Nice site to have Dusty. Thanks

 

[dusty-t]

Thanks Bulldog, I think it was Handyman or Traildust put me on to that site.

 

[Bulldog]

I looked around at all kinds of tings on there last night. That site has some good info and the piece by piece breakdown if very helpfull.

I think who ever found it first really hit a homerun.

 

[dem45133]

B6100HST Hydrostat problems, update

Hello again all.

Well, I finally got home to Ohio and saw this B6100HST for the first time in person. Its as I thought overall, runs well, but still have HST issues.

I took it into our local Kubota dealer and the pressure tests were border line cold and next to nothing warm. I drove it and test operated from cold to warm.. pump sure seems strong reverse and forward will spin the tires in low range, and sorta over stresses with that hydro wine when punched in high range (as one would expect with a hydro I'd think). Consensus seems to be that they think when the oil get warmed up and lighter in viscosity that it blow past the ???, but if it were that... at least to me it wouldn't work as well as it does cold.

The dealer didn't want to go into any further with out asking as it would require opening it up and the labor would be about the same as it would have been to just install a new unit... but that's better than $2.2K to do... and bring my investment to better than 5K. So the project is on hold until I can be home long enough to do it myself.

Are there better options than the $1283 plus tax for a new HST unit? He figured about 12 hours labor at 65/hr or about 900 more to install... so I'm going to have to do it myself. Are there rebuilt or remans available?

I'll be studying some more in the service manual. I'm not sure what viscosity the oil is the hydro is using... but if it is blowing by warm as they say... what would happen if one ran a heavier viscosity oil?

And so the the B6100HST saga continues....

Dave