B7100 Hydro Inop

[dlumpy5282]

Found this awesome forum searching thank you

hydro was working fine now just quit not check anything yet but fluid so not sure where to start

 

[eserv]

First thing to check is whether the PTO works. If it does then check the HST suction screen and install a new HST filter. ( HST screen is on the left side under the rear axle)

 

[dlumpy5282]

I replaced filter and removed screen how do I know if screen is plugged I can fill the inside of it and nothing comes out of it so does that mean it is blocked and is there a way to clean, pto does work

 

[dlumpy5282]

I think I got the screen clean but need to know do I fill and check while off or while engine running

 

[dlumpy5282]

I got fluid in and it pulls for a short while and then stops and no resistance on pedal. I then wait and move pedal back and forth and it starts moving again and then will stop and same over and over

 

[eserv]

sounds like low or no charge pressure. Remove the Hydrostatic oil filter. ( the one on top) if there is no oil in it you have a failed charge pump. If you crank the engine with the filter off you should have oil come out of the filter mount.
If the PTO works it indicates that the clutch, drive shaft coupling and HST input spline are OK because the drive has to come all the way through them to turn the PTO
Ed

 

[eserv]

By the way, was there any sign of water in the hydraulic oil? A little water will freeze in the charge pump and cause it to break the rotor! ( it is a gearotor type pump) another good reason to change that oil regularly!
Ed

 

[dlumpy5282]

The fluid maybe a little milky would ithe filter is open down the fluid drains from it but was fluid at the mount and would it be best to remove charge pump and check it?

 

[eserv]

It's not easy to remove the charge pump. make sure you have good oil supply to it, after that you need to have gauges to check it out. Or you could just take it apart to find the problem but that way you don't really know what to look for.
Ed

 

[dlumpy5282]

I guess a big question the screen by the left axle how do I know it is clean I can put fluid inside and nothing comes out?

also this morning cold it would not pull then the pedal would start getting resistance and start to pull and quit sooner it does seem to come back quicker in reverse

 

[eserv]

That screen shouldn't hold oil at all. The Hydro depends on free flow of oil from the sump to the charge pump. If that screen is clogged you will have a no charge pressure condition. What is it so plugged up with? Maybe a new one is in order? If it is plugged the Hydraulic screen on the other side is probably plugged up too, this will not effect the Hydrostat but it will damage the hydraulic pump.
Ed

 

[gktilton]

So how cold is it outside, how milky is this fluid, and how long have you let the tractor run. Before I invested a $ in parts or ripping anything apart I would drain the fluid from the bottom of the rear end case, both sides and toss it. Go to Tractor Supply or whatever you have out there and get a $30 pail for universal Hydro/Transmission fluid and fill that sucker up. If the cold thick fluid couldn't get through the screen to the pump nothing is going to do a thing, if its milky and its cold out it will thicken just enough to not pass through. Clean the screen with some kerosene to make sure nothing is clogging it, kerosene should flow through it easily.
Kerosene and $30 worth of fluid and you will know if you have a strainer/fluid issue or you need to rip apart and look for whats broken.

 

[dlumpy5282]

its about 40f out and I tried cleaning the screen with carb cleaner and can fill insiade with card cleaner and very little comes out and its alot thinner then hydro fluid so i just order3ed a new screen and hope that fixes it. Will post next week when part comes in

 

[dlumpy5282]

should the screen be flexable or should it feel solid like around a pipe?

 

[Kubota Newbie]

You should probably avoid running the tractor with a low or no charge situation to the hydro unit. I've no experience with the 'bota unit, but the sun-strand type hydro units used by many other manufacturers DO NOT react well to that condition. The pistons in the hydro spool will cavitate without oil pressure behind them causing the "foot" that slides on the swash plate to slap against the plate, sometimes breaking the end of the piston assembly and ruining the swash-plate.

 

[dlumpy5282]

Thanks for the help got the new screen in today and filled with fresh fluid and working like new.

Next question= is there a spring or something that brings the pedals back to neutral?