Greetings folks, just to give you a little background on me I like projects. Never been scared to turn a few wrench痴. Not just for the money savings, But mainly because I just don稚 trust any main stream shops for just about anything anymore. That being said I am currently looking a B21 TLB that has 2500hrs on it. The tractor blew a couple hydro lines so the owner decided to change the hydro fluid after replacing the lines. He says he put actual Kubota fluid in it. Ever since then it doesn稚 want to move. FEL and BH still very strong and can move the tractor. But when you are on the Pedal it whines and doesn稚 want too move foward or backwards. You can see it痴 trying almost like if you got all four wheels or the ground with no resistance they would probably spin slowly. If you mess with the FEL and or backhoe. It will start to move but nothing sustained. He says the folks he has talked to say it痴 either the hydro pick up screen clogged or there some type of 斗ever (valve maybe) that diverts the hydro Between the FEL/BH and the HST and he think it maybe stuck in position. He also doesn稚 think the pump is bad because the FEL and BH are still working flawlessly. My research is telling me it sounds like it possibly could be the pick up. Just because if it has never been checked with 2500hrs on the machine when draining out the fluid I could see how it could end up clogging said screen, or I am wondering if it痴 possible a relief valve could be stuck open on the hst causing it to not want to move, but sound like the hydro is in overtime when the pedals are pushed. Any feedback is greatly appreciated if your familiar with any of the systems. Thanks in advanced for your time if you even just read this far. New here so I can post a video if needed/after I learn how.
B21 doesn稚 want too move after a fluid change.
- Thread starter MpughII
- Start date
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RjCorazza
Elite Member
Not a hydraulics guy, but I used an aftermarket transmission filter (suction) on one of my Kubota ZD mowers and had similar symptoms. The machine would not move and whined. Replacing the filter with OEM and worked fine.
Sure sounds like total starvation for fluid.
Sure sounds like total starvation for fluid.
fruitcakesa
Veteran Member
Does the trans have to bled of air after a fluid change?
Not the same tractor, but I did a fluid change in my T1400 lawn tractor and was never able to get it to run right after.
I bled the heck out of it and it would work for a while but after a short time it would stop moving.
I ended up selling it to someone who felt it was worth trying to fix.
Not the same tractor, but I did a fluid change in my T1400 lawn tractor and was never able to get it to run right after.
I bled the heck out of it and it would work for a while but after a short time it would stop moving.
I ended up selling it to someone who felt it was worth trying to fix.
goeduck
Super Member
I bought a used B21 with 1500 hours and wanted to change the suction screen to make sure it was clear. It was spotless. But that does not mean yours is. I thought there was just the one pickup and, if so, since your FEL and hoe work, it must not be clogged. I know there are 2 filters so maybe there is a second unscreened pickup?
CurtisC
Bronze Member
Did owner changeout the hyd.filters when he changed the oil and if so, did he use anything other than Kubota filters? Also, what kind of "Kubota Fluid" did he put back in? I've got a B26TLB and it doesn't like anything other than Super UDT2. After 400 hr servicing I had a louder than usual HST whine issue and in really cold weather the pedal would lock up refusing to go into FWD or REV protesting loudly when you tried to push the pedal. It turned out the WIX HST filter and maybe the Hydraulic filter I used during the servicing were bad. After changing back to Kubota filters - no issues. Even if he didn't change filters I'd toss em and replace with OEM in case they got clogged. It sounds like the HST is fluid starved. A fresh load of Super UDT2 and new OEM filters won't set you back too far ought to be ruled out before you start looking at the pump or HST. After inspecting the suction line from tank to pump, if there's any concerns that could reduce flow or introduce air, replace what's suspect. There's also a 90 deg rubber elbow in the suction line on the B26 just before pump inlet and I'd assume there's some kind of similar rubber connection to the pump on the B21 which could be cracked (leaking air and causing pump cavitation) or partially collapsed starving the pump and subsequently the transmission. I changed out the elbow on mine just because the part wasn't that much vs. the work to get it out to inspect. The pickup screen could be clogged but I'd put that at the end of the list of things to look at just because its internal and it takes a lot of trash to clog it up. Again just thinking about relatively easy things to rule out before taking on a major effort to tear down /inspect the pump or transmission. Good luck!