Kubota M59 Problems and Solutions

[fishmanburris]

Hi all,

I have had a Kubota M59 for a couple of years now and have benefited from the experience of others, especially those that post on forums like this. I thought I would share my experience so that others can benefit as well. Here's a start:

Common Problem #1: M59 Slow swing speed of backhoe.
Solution: Frequently cycle selectors that control hydraulic flow to allow switching from backhoe to 3 point operation. These are located on back of tractor near the top of the 3 point hitch Essentially wires with loops in the ends. Note: This is likely not an issue if you use the tractor's 3 point hitch regularly.

Common Problem#2: Obstruction of heat of hydraulic fluid heat exchanger. This is located in front of the radiator and protective screen and tends to get coated with dust/dirt. Failure to keep this clean will result in excessive fluid temps.
Solutions: Remove the plastic cover in the front (two bolts with plastic nobs on top) and hose out.

Not Common Problem?#3: M59 does not operate smoothly when going forward OR reverse. Tractor jerks or gets stuck in forward or reverse...
Solution: The shop manual suggests the following for this problem: A) Replace Pedal Sensor; B) Change Transmission Filter; C) Replace high pressure bypass valve. I did all three of these and it did not fix the issue. What Worked: Replace the affected (forward or reverse) control solenoid. Also known as VALVE (HST, PRO) (TD170-59310). You can see/buy this at: colemanequip: HST-SERVO-REGULATOR-COMPONENT-PARTS-84655/

Note this issue may affect other Kubota tractors with the HST+ transmission. I'm not a big fan of the extra complexity added for the HST+ (compute, sensors and actuators) over the tried and true standard HST. There are a lot more things to go wrong over time with this setup...

For those new to the M59, there is a way to access the computer's diagnostics without a scan tool. Let me know if you need help with this.

What problems/solutions have you experienced?

Fishman

 

[mikester]

What year is your machine?

 

[FatTire]

I hear what you're saying about the added complexity of HST+, but my impression is that very few owners ever have problems with it. Having the split ranges is fantastic.

 

[fishmanburris]

My M59 was first sold in 2012. It currently has about 1100 hour on it. Previously owner bought new and had some paperwork, however not sure how much maintenance he did...

 

[fishmanburris]

I don't see a lot of issues reported with the HST+ either. That is one reason I wanted to post my issue in case someone had a similar problem. That said, it is good that they are reliable, because they are actually quite complex. I'm fairly experienced with trouble shooting complex electronic systems, but for those who are not and have a problem....good luck. I also hope the electronic parts remain available for the life of the tractor (25 years?). Most of these are unique to Kubota, so very little aftermarket support. Kubota parts prices seem to be generally reasonable, but this particular solenoid was almost $300. That combined with the replacement of the pedal position sensor, filters and UDT fluid meant this was a $1000 job without factoring labor...