Tranny started makeing funny clacking noise and some feedback on the pedal that had the vibrating rythem of the clacking so I headed back to the garage. Barely made it. The sound was a clacking mixed with a hard hydro whine. Checked and found fluid level low but on the the stick. Refilled and had same symptons. Put tractor on jackstands and checked and cleaned screen finding a reasonable amount of metel flake and dust. Replaced fluid and filter and restarted. After ten minnute run I check pedal and got nothing at all. Three point working as well as both PTOs. Hmmmmm. I had just removed the backfill blade and trencher about a week ago and also removed the valves and associated plumbing. At the aux hook up block I placed a hose from the out to the in and capped the return on the side of the tractor. Rethinking this I replumbed one of the valves back in the system taking the out of the aux block to the in on the valve. The power beyond from the valve back to the other side of the aux block and from the out of the valve back to tank. This was a change that put fluid back in at the point of the tank that had been dry with only the hose from aux port a to port b. Now I start the tractor and manipulate the hydraulics to remove any air that I could. After a breif run in I try the pedal and find I was back to square one so I analize once again. At about quater to half throttle the tractor (still on jack stands) apears to pull but still with the same sound and and feel at the pedal. Between half throttle and about three quarter there was no increase in speed and from three quarter to just above the wheel movement stopped like the clutch had been depressed. This proved to be repeatable. Before I called it quits, I realized that the return to tank from aux valve was not tight but showed no sign of fluid spillage. I removed the hose connected and had fluid coming out of the return port so I think I had flow from the valve out to tank in but pressure was not sufficent enough to leak. So now I'm thinking I smoked the hst or it's an air leak situation. I search and read the forums and see all the attention that the strainer gets and I've eliminated that. I see no test or procedure to confirm the drive good or bad and cost on rebuild kits is higher than a new hydro unit complete. So now I'm thinking if I got to replace it I might as well check it out. I've got the parts CD and thus the exploded view and I see that this is not for the weak I heart but what the he**. The tractor is now in several pieces and the hst is on the bench wating for surgery and I am looking for someone who speaks kubota hst before I crack it open. If you're out there I'd really appreciate your opinion and assistance.
B2400 HST Hydrostat Problem Short Version
- Thread starter taftalw
- Start date
Hi Taft. Wow this does not sound good. Before I ripped into that hydrostat unit I would wait for some replies. As far as I know the hydraulic system and the hydrostat system are two different systems that use the same reservoir.Did you check the clutch play before you tore it apart. Did you change the hydraulic filter. Hang tight for a day or so if you can. There are some guys on here that really know their Kubota's. They can save you a lot of grief some times. Good luck and keep us posted
Dusty
DustyThanks for jumping in Dusty. In reading yesterday I saw there was some knowledge available so I'm going to do as you said and sit tight.
Well its been some time and I am now at the point of putting the tractor back together. After a couple of months without any feedback of what I might do I tore into the unit to find that a couple of the pistons in the tranny had beaten themsaelfs to death. Still dont know how this occured. I forget now whether it was the constant speed pumb or the variable speed motor but two of the pistons looked like they had stopped in rotation and just beat the tops right off. I took both cartridges to my brothers machine shop and made replacement parts from tool steel. I had also found that the charge pump had gotten pretts chewed up when the framents pass through it. Yesterday I pulled the broken beast into the shop areas and started cleaning everything and will by Monday should have it ready to test, I'll report as to the sucess or failure of this later.....
the usual cause for smashed up pistons is low or no charge pressure. Be really sure that charge pump is working good and the HST suction screen is clean.
Ed
Wow, its been ten years since this hydrostat problem became the thorn in my paw. By the grace of God I was able to tear down this beast and fab replacement parts and put it all back together. Adding to the task was the fact that it was all in boxes for maybe three months. The kubota dealership wanted no part in repair but did offer to install a new or used tranny in the machine. I find myself today ordering a starter and key switch for the machine and if I can find the parts for the charge pump I think Ill replace them as it does start to whine when it gets hot and I imagine this is the cause. Just another day in the life. The only other task that comes remotely close are the many electrical issues that Ive chased down on my E34 BMW. Thank you Jesus for being in my life to shine a light on my darkest days.
I am impressed. Both by your success at fixing the original problem, and by your possibly setting a record for the longest time between thread updates!