Tractor will not move in forward after running for an hour, but will travel in reverse fine, any ideas out there?
L3010 hst
- Thread starter mlivengood
- Start date
Typically when you have a function going south when the fluid gets warm or thinner, you have some wear that's causing a bleed off of pressure.
You need to get it into the dealer and have them pressure test the hydrostat after it's been under load to create heat in the system by running a piece of equipment or a hydraulic load tester.
With out the service manual in front me and some test being done first. I can only assume looking at the parts break down that the HST swash plate on the forward side has some wear or possibly be warped? Causing the slipper feet on the pump rotating group to lose contact or bleed off pressure.
Pat
You need to get it into the dealer and have them pressure test the hydrostat after it's been under load to create heat in the system by running a piece of equipment or a hydraulic load tester.
With out the service manual in front me and some test being done first. I can only assume looking at the parts break down that the HST swash plate on the forward side has some wear or possibly be warped? Causing the slipper feet on the pump rotating group to lose contact or bleed off pressure.
Pat
whitetiger
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Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Need to pressure test for forward servo or relief valve failure. If it has power in reverse then swash plate and rotating group are OK.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
First thing to check is the pedal linkage etc looking for obvious damage or interference. The linkage has several parts that can get bent, broken, blocked.
Inside the HST the rotating group could have a seal plate leak that would affect one direction. Internal repairs can be expensive so its good to know as much as possible before tearing into it.
It would help if you describe its behavior a little more. When its hot will it move forward in any gear range (L, M, H)? Does it make any new hissing noises? When it starts from cold, does it operate normally in forward and in reverse? Any speed differences? How many times has this happened? Always after running?
My L48 has the same HST unit as the Lxx10 tractors. When I got it, forward was fine but it had nearly dead reverse (worked weakly in L and M). It had a regulator issue affecting reverse. TBN thread here.
BTW, the high-pressure relief valves for forward and reverse are identical so they could be swapped as a test. If its a relief valve issue the problem should swap directions.
With more detailed description of how it acts it will be clearer to know what to look for. I found very little diagnosis or repair info is available - even in the WSM. Kubota's advice for many kinds of malfunctions is to just replace the whole HST unit. This one is priced around $4400 plus labor. Dick B
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Thanks to all who replied, Tractor runs fine for about 1/2 hr. than it will start to get slower moving in forward no matter what range it in. It has no noticeable noises. Tried switching relief valves from reverse side made no difference. Has all new Kubota oil & filters.
I might also add that the pedal sticks, thinking about pulling regulator off or adjusting bolt to center piston
rbargeron
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Lifetime Member
Equipment
L5450, L48, L3250, L345 never enough attachments
Troubleshooting an HST can be tricky - not to mention potentially hazardous. I've sent some ideas to you by PM. Dick B
whitetiger
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Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
I have found a few L series that had relief valves fail intermittently. They can start out working and then quit and work again later.