New B7100 owner with some hydrostatic tranny problems

[Tibeka]

Hello!

I recently picked up a B7100 HST 4x4 with loader that has only 400 hours on it. The big issue with it is it was used by a local mall to load salt for the parking lots and the sheet metal is all rusted pretty badly. I can't really complain cause the price was too good to pass up. Since new parts almost sent me into shock I started looking for a nice parts machine and I finally found one.

It's a nice B7100 2WD with just over 2000 hours on it. The guy traded me on a car dolley I had and I'm supposed to go get it this Saturday. The motor runs great but it has a problem with the hydrostatic tranny.

It will run great with plenty of power but only until the fluid warms up. Then it still moves but won't climb any hills and has no power.

I got this tractor for parts but now that I think about it, it would be nice to fix it and use it. Can't have too many tractors .

The PO was very honest about the issue. He just traded for the tractor and changed the filter but that's about all he did and it didn't help. The tractor was used on a golf course to pull a reel mower and that's it.

I don't know a lot about hydrostatic trannys. Is it possible it just has the wrong fluid in it? Could it be a clogged pickup tube or screen?

2000 hours doesn't seem like a lot to me. Would the hydro be toast after only 2000 hours?

My thought was to drain the fluid, clean all the screens and filters and put all new fluid in with some Seafoam tranny flush and see if that might fix it.

What say the experts?

 

[Eric McCarthy]

I'd say your on the right track. Flush and change the fluid, clean the screen and replace the filter. Could have the wrong fluid in it. Look for a UDT tranny fluid that can be found most anywhere. Wal-mart sells it as do most auto stores. Somebody could have put in gear oil thinking that will work.

This article here will explain how to change the filter screen on a B series
http://www.orangetractortalks.com/2...uction-screens-everything-you-wanted-to-know/

And this video will give you the low down on hydraulic fluids!
http://www.youtube.com/watch?v=WeaolHWdslg&list=UUcyNCAXVF1omL2z3M8kN3QQ&index=14

 

[Tibeka]

Thank you for the fast reply!

I plan to bring it home Saturday and I'll see if I can't get on it right away. I'll be sure to report back what I find.

 

[hodge]

Since he replaced the filter, I'd say the next place to look is the screen. At the least, it's worth pulling and cleaning yourself, but hopefully it is just gunked up, and restricting the flow. Take the obvious, cheap route first! I just learned that lesson. My Dodge/cummins quit on me, and after installing a fuel pressure gauge, I determined that the injection pump wasn't getting fuel. So, I replaced the lift pump, ran new fuel lines, deleted the fuel heater, put in a new prescreen, and installed a new overflow valve- all stuff that probably needed attention, anyway. But, the problem was at the other end- a tablespoon of goop clogging the end of the pickup tube in the tank. If I had started at that end first, the simple end, I would have had it running for free. Live and learn.

 

[Kubota Newbie]

The symptoms described tend to indicate
1). A weak charge pump, or
2). Excessive clearance in the hydraulic rotor/piston assemblies, or
3). Incorrect oil or additive that is allowing it to foam as it gets warmed up/used more. (air bubbles won't transfer energy like fluid, hence no "go" if lots of foam/bubbles)

2). Is unusual with any hydro assembly (unless it's making funny noises).
1). Is common on high hour machines, can sometimes be repaired economically depending on which parts are worn. Usually not so bad that it will cause a machine to loose all motion.
3). Hope that it is "3", easiest thing to fix.

BTW, I like to golf, and the course super at the local club is a nice guy, but I wouldn't let him change the oil in my car. There's a reason they lease their carts.

 

[Big Kahuna]

You're thinking on the right track, pick up screen dirty, wrong oil, make sure the cooler up front is not blocked, my need to go to the radiator shop and get cleaned. I have 2 of these and they are like tanks, one whines a little more than the other but both run good.



Good Luck ! Big Kahuna

 

[Apogee]

Only other thought is if someplace in the hydraulic system there is an air leak. It could also cause the oil to foam and I agree that I also think that is your problem. Check the hydraulic block and any return lines for leaks/drips/cracks. You should see oil seepage if this were the case...

Good luck!

Steve

 

[Tibeka]

Figured I would post an update even though I don't have much of one to post. I got the tractor home and my Dad and I have taken turns trying to get the tranny to give any sign that it is 'weak' as the PO said but we have never had a problem with it. I drove it around for 20 or 30 mins one night and it had all the power in the world. This thing will almost pop a wheelie if you aren’t careful . The PO seemed to know what he was talking about but we can't replicate the issue.

Is it possible the fluid needs to get fairly hot to cause it to slip? Maybe only under a load?

I still plan to change the fluid but I haven't gotten to it.

Could the PO have done something else that would have caused this?

 

[Stumpy]

Consensus seems to be change the fluid and work from there and I agree. Symptoms seem to fit foaming oil. He may have put in the wrong stuff or just has never changed it. Also check the radiator and oil cooler up front for blockage, make sure they've got good air flow.

 

[Tibeka]

OK, finally ready to post an update on this issue.

I drained the old fluid, pulled the screen and cleaned it and filled it up with fresh UDT. The tractor seems to run great now. It won't fly out of the hole or anything but I hooked it to a tree and it has no problem spinning the tires in Low range. High range it just bogs down but I wouldn't expect it to do too much in high.

Hopefully this is all it needed.