L5030 with HST will not move forward when shuttle petal is depressed and the forward shuttle pedal position seems "limp" (no resistance when depressed). Will drive normally in reverse when the pedal is depressed for reversing. Linkage that is exterior to the cast iron case is all normal. Suggestions as to how to proceed please. Thank you.
L5030 No Forward Movement
- Thread starter jdmikeska
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Russell King
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North Idaho Wolfman
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Thanks for the HST Manuals. The HST seems like an extremely complicated system. Are the Kubota dealership mechanics likely to be able to repair this problem successfully. Cost to separate the tractor (to allow access to HST) is $4000 +. Then they start troubleshooting.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
Loss of Forward motion but with Reverse still working, MAY not be a disastrous situation.
A few years ago I bought an L48 which was ok going forward but was very weak in reverse. There's a long saga starting here about how it was eventually fixed (has been fine now for a long time).
The HST in my L48 is similar in operation to yours, being mechanically controlled without external electrical valves like the later ones.
Kubota's troubleshooting pages for HST's very often lead to "replace the unit". One reason for this is the high-precision of the mirror-finish internals. If any anything is scratched or broken the device is often not salvageable, especially in any shop that doesn't have "clean room" conditions.
A high percentage of HST functional issues are due to OUTSIDE linkage being damaged or bent. Before taking anything apart be very sure all the externally verifiable conditions line up.
To give you some slightly less menacing news, many of the quite-expensive parts inside the HST accomplish both forward and reverse motion, so if its symptom-free in reverse there's a possibility the problem is the (1) regulator, the (2) F-R reversing hydraulic cylinder, or (3) the cradle bearings. It is possible the big-dollar parts are still ok.
Unfortunately - with the exception of externally accessible relief valves, the machine will need to come apart to replace components inside the HST.
I'll try to list more links and maybe some ways to check things from the outside - more later.
Dick B.
A few years ago I bought an L48 which was ok going forward but was very weak in reverse. There's a long saga starting here about how it was eventually fixed (has been fine now for a long time).
The HST in my L48 is similar in operation to yours, being mechanically controlled without external electrical valves like the later ones.
Kubota's troubleshooting pages for HST's very often lead to "replace the unit". One reason for this is the high-precision of the mirror-finish internals. If any anything is scratched or broken the device is often not salvageable, especially in any shop that doesn't have "clean room" conditions.
A high percentage of HST functional issues are due to OUTSIDE linkage being damaged or bent. Before taking anything apart be very sure all the externally verifiable conditions line up.
To give you some slightly less menacing news, many of the quite-expensive parts inside the HST accomplish both forward and reverse motion, so if its symptom-free in reverse there's a possibility the problem is the (1) regulator, the (2) F-R reversing hydraulic cylinder, or (3) the cradle bearings. It is possible the big-dollar parts are still ok.
Unfortunately - with the exception of externally accessible relief valves, the machine will need to come apart to replace components inside the HST.
I'll try to list more links and maybe some ways to check things from the outside - more later.
Dick B.
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Thanks for your input. The external linkage looked ok to me and the folks at the local Kubota dealership felt that all was good with the external linkage as well. They then told me that it would cost $4,000 to open up the machine and then trouble shooting would start. Said cost of repair could be as high as $16,000.00. That really got my attention. The troubleshooting flow sheet in the Workshop manual indicated that loss of movement in one direction (but not both) was caused by a failed pressure relief valve. Debating whether to take a chance on repair or sell the machine to a salvage yard. My problem that I keep grappling with is: "can I trust the dealership to repair the HST without causing another problem down the line". Warranty on their work is only 90 days. So, if they muck around in the HST are they going to cause some damage that will require another $4,000 splitting of the machine next year? Machine probably only worth about $12,000 if fully functional.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
When I first got my l48, I took out and interchanged the two high-pressure relief valves, reasoning that the symptom would change from weak reverse to weak forward. It made no difference but that's because the problem was in the cradle bearings.
It sounds like your confidence in the dealer is not very high. Dealers with no HST repair experience (which is MOST of them) throw the big estimates around because they don't want to quote too low and be in a jam later if the news on discovery is bad.
My suggestion would be to do some tests - like trying the relief valve swap, yourself (or with a helper?) so the machine is not a hostage in someone's shop. Maybe look at other temporary tractor if the need justifies a rental or buying a 2nd machine and selling it later ?
Is there ANY response in Forward - in low range, mid-throttle ? Follow the WSM to take out and interchange the two high-pressure relief valves before anything else.
It sounds like your confidence in the dealer is not very high. Dealers with no HST repair experience (which is MOST of them) throw the big estimates around because they don't want to quote too low and be in a jam later if the news on discovery is bad.
My suggestion would be to do some tests - like trying the relief valve swap, yourself (or with a helper?) so the machine is not a hostage in someone's shop. Maybe look at other temporary tractor if the need justifies a rental or buying a 2nd machine and selling it later ?
Is there ANY response in Forward - in low range, mid-throttle ? Follow the WSM to take out and interchange the two high-pressure relief valves before anything else.
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rbargeron
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L5450, L48, L3250, L345 never enough attachments
The HP relief valves are shown on WSM pages starting at 3-S89. All you'll be doing is taking them out - with the engine NOT running. When the plug (1) is taken out about 2 or 3 gal of UDT fluid will drain out (have a CLEAN container ready).
Here's an excerpt from WSM page 3-S122 showing that the forward valve comes out the bottom, and reverse comes out the top. Since the forward relief is suspected to be acting up, maybe just take that one out first, checking for debris or something holding it open allowing it to leak by.
Hope this is helpful. Best luck. Dick B.
Here's an excerpt from WSM page 3-S122 showing that the forward valve comes out the bottom, and reverse comes out the top. Since the forward relief is suspected to be acting up, maybe just take that one out first, checking for debris or something holding it open allowing it to leak by.
Hope this is helpful. Best luck. Dick B.
Thanks for the info. Adds clarity to what I have found so far. I accessed the WSM troubleshooting flowchart for " no forward movement" and the resulting solution was to check the pressure relief valves, as you suggest. I assume that the photo depicts the HST? Is this unit accessed after "splitting the tractor" or are the pressure relief valves accessed from the outside without the necessity of "splitting" the tractor?
rbargeron
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If you take a look at the machine under the left side you'll recognize the HST unit right behind the engine. That photo is from a part of the shop manual where everything is shown disassembled for clarity - the machine is in pieces - hopefully yours wont need that.
The high-pressure relief valves are accessible from the outside without splitting the tractor.
If checking the reliefs yourself isn't your cup of tea, maybe look for a mechanical friend. Too bad you're not in New England - I'm retired and work for beer!
The high-pressure relief valves are accessible from the outside without splitting the tractor.
If checking the reliefs yourself isn't your cup of tea, maybe look for a mechanical friend. Too bad you're not in New England - I'm retired and work for beer!
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Thank you so much for the info. Tractor is in local dealership shop. Now that I am a bit more knowledgeable, I will go in and talk to them about their troubleshooting protocol. Or may just bring home and check pressure relief valve myself. Thanks again for your help.
rbargeron
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L5450, L48, L3250, L345 never enough attachments
What we're looking for is extra junk in/around the valve bore that could be holding it open. The pressure is high so a tiny metal shaving could be affecting performance. A new valve TD060-59000 costs around $400 so its worth a close look before just replacing one.
Below is a screenshot of the parts page showing the two HP reliefs - parts 200. Notice there's another plug just ahead of the Forward relief - that one is not involved in the swap.
Below is a screenshot of the parts page showing the two HP reliefs - parts 200. Notice there's another plug just ahead of the Forward relief - that one is not involved in the swap.
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whitetiger
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You had better find another dealer, $1800.00 should have the hydro unit removed, sitting on the bench.
It seems like my dealer is trying to discourage me from continuing with repair. The service manager insists that cost would probably run about $14k and could go as high as $18k. Whether they replace the HST or repair by replacing parts. My take on the whole thing is that they don't feel comfortable with dealing with it or at least don't want to deal with it. So I will have the machine brought home. Might look for an independent shop.
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