Hi All,
New member here from Wales in the UK.
Please bare with me on this one as I am new to hydrostatics, very mechanically minded, just new to HST stuff.
I bought an old '83 (I think) B7100 HST 4x4 from family, they had bought it about 2-3 years ago, used it for an hour and set it aside until they had time to fix it, they experienced the same problems as I and in the end bought a newer machine so that I could have this one.
My problems are as follows:
When I first bought it there was an issue with the trans where it would drive normally for a while, if a little loud (all my comments about running, stopping, noises, vibrations etc are aimed at the trans as the engine is near perfect) it would drive ok with revs down low, but as soon as you were on high revs it would just stop and the F/R pedal would do nothing, no noises no nothing, was like as if you weren't touching it.
You would then need to lower the revs to get it to move again, and the trans was very loud and quite often it was very jerky and was giving a lot of vibration back through the pedal, sometimes even fighting against you, then its a case of repeat the process etc.
A visual inspection through the oil filler hole showed a lot of frothing of the oil so......
I drained down the oil and found it to be full of what seemed to be ATF fluid? I took a small clean sample of it and bottled it in a clean clear bottle, fluid was red in colour and when shaken would hold a lot of air in suspension.
I removed both strainers to clean them up, what I found was that there was a lot of mulched paper type deposits on them, more on the hydraulic strainer then the HST one and some also came out when I drained the oil, in light of this I decided to leave the filter in place and strain the oil and put it back in to try to 'flush' some of whatever was in there out, tractor ran slightly better for all of about 10 minutes, where it reverted back to the same issues with stopping.
After it was warm I then drained the oil again from all 3 drain points to get as much of the sludge out as possible, allowed it to drain for a good few days while I did some other jobs.
New genuine Kubota HST filter fitted, screens cleaned again and brand new Kubota UDT back in it and it was still a little noisy but seemed to go like a rocket!! Alas it was not to last, it is a LOT better than it was but I'm still having issues.
The second time I went to use it after new fluids and filters I cou7ld not get it to move for about 15 minutes, all levers were where they should have been, so no mistakes with it being in neutral, but it just wouldn't move, pressing the pedal in either direction would do nothing, just a small barely noticeable sound if you got really close to the HST unit, this symptom is the same every time it won't move.
when it's actually driving and I'm creeping along it'll sometimes stop by itself, and I'll need to lower the revs right down to almost idle to get it to 'pick up' the drive again, sometimes it'll do this smoothly, other times it'll jerk, vibrate, bounce, fight back against the pedal or sometimes all of the above, the noise when it is fighting back is horrendous, other times it just won't move at all for a good length of time.
All symptoms happen in both forward and reverse, it makes no difference.
Other times when its driving, if I need to keep my foot on the pedal for a constant speed, it may well be fine, but if I need to stop for a split second for some reason, it goes back to the pedal not doing a thing and having to drop the revs again.
What I have noticed is that if I'm going down a slight slope, or over a bump where it makes the tractor move quicker than the trans, even if only for a split second, it'll stop all drive again.
Also from reading other posts I thought I would note the following: when it's lost drive, I can freely push it back and forth or have it roll if I'm on a hill.
I have a video of it which I'm currently uploading to youtube, I'll post the link when this site allows me to, however you can search for it on my youtube channel under "Rob Mogs"
Apologies for the quality of the video as I had a flail mower on the back in some quite heavy rushes! I can get a video without the mower running if needed.
Any help, or suggestions would be great.
Even a list of machines that use the same HST unit.
I'm no stranger to tearing unfamiliar units apart, but don't want to pull it apart if spare parts aren't available.
Thanks for your time folks.
New member here from Wales in the UK.
Please bare with me on this one as I am new to hydrostatics, very mechanically minded, just new to HST stuff.
I bought an old '83 (I think) B7100 HST 4x4 from family, they had bought it about 2-3 years ago, used it for an hour and set it aside until they had time to fix it, they experienced the same problems as I and in the end bought a newer machine so that I could have this one.
My problems are as follows:
When I first bought it there was an issue with the trans where it would drive normally for a while, if a little loud (all my comments about running, stopping, noises, vibrations etc are aimed at the trans as the engine is near perfect) it would drive ok with revs down low, but as soon as you were on high revs it would just stop and the F/R pedal would do nothing, no noises no nothing, was like as if you weren't touching it.
You would then need to lower the revs to get it to move again, and the trans was very loud and quite often it was very jerky and was giving a lot of vibration back through the pedal, sometimes even fighting against you, then its a case of repeat the process etc.
A visual inspection through the oil filler hole showed a lot of frothing of the oil so......
I drained down the oil and found it to be full of what seemed to be ATF fluid? I took a small clean sample of it and bottled it in a clean clear bottle, fluid was red in colour and when shaken would hold a lot of air in suspension.
I removed both strainers to clean them up, what I found was that there was a lot of mulched paper type deposits on them, more on the hydraulic strainer then the HST one and some also came out when I drained the oil, in light of this I decided to leave the filter in place and strain the oil and put it back in to try to 'flush' some of whatever was in there out, tractor ran slightly better for all of about 10 minutes, where it reverted back to the same issues with stopping.
After it was warm I then drained the oil again from all 3 drain points to get as much of the sludge out as possible, allowed it to drain for a good few days while I did some other jobs.
New genuine Kubota HST filter fitted, screens cleaned again and brand new Kubota UDT back in it and it was still a little noisy but seemed to go like a rocket!! Alas it was not to last, it is a LOT better than it was but I'm still having issues.
The second time I went to use it after new fluids and filters I cou7ld not get it to move for about 15 minutes, all levers were where they should have been, so no mistakes with it being in neutral, but it just wouldn't move, pressing the pedal in either direction would do nothing, just a small barely noticeable sound if you got really close to the HST unit, this symptom is the same every time it won't move.
when it's actually driving and I'm creeping along it'll sometimes stop by itself, and I'll need to lower the revs right down to almost idle to get it to 'pick up' the drive again, sometimes it'll do this smoothly, other times it'll jerk, vibrate, bounce, fight back against the pedal or sometimes all of the above, the noise when it is fighting back is horrendous, other times it just won't move at all for a good length of time.
All symptoms happen in both forward and reverse, it makes no difference.
Other times when its driving, if I need to keep my foot on the pedal for a constant speed, it may well be fine, but if I need to stop for a split second for some reason, it goes back to the pedal not doing a thing and having to drop the revs again.
What I have noticed is that if I'm going down a slight slope, or over a bump where it makes the tractor move quicker than the trans, even if only for a split second, it'll stop all drive again.
Also from reading other posts I thought I would note the following: when it's lost drive, I can freely push it back and forth or have it roll if I'm on a hill.
I have a video of it which I'm currently uploading to youtube, I'll post the link when this site allows me to, however you can search for it on my youtube channel under "Rob Mogs"
Apologies for the quality of the video as I had a flail mower on the back in some quite heavy rushes! I can get a video without the mower running if needed.
Any help, or suggestions would be great.
Even a list of machines that use the same HST unit.
I'm no stranger to tearing unfamiliar units apart, but don't want to pull it apart if spare parts aren't available.
Thanks for your time folks.
