F3060 HST Speed Control Pedal Sticking

[arto98607]

Looking for suggestions hopefully from those who have worked on this type HST


My F3060 has 3600 hrs. and I have partially disassembled it, mainly due to sticking HST pedal and couple of hydraulic oil leaks in the front axle housings (both sides), which have already been repaired and the speed control linkage has been reassembled with couple of worn pieces replaced.
The speed control linkage was actually working smoothly even before disassembly, but only when the engine was not running.

I.E.
It always moved smoothly to forward position with the engine running or not, but it was sticking when trying to move it from forward to reverse, whenever engine was running and the mower moving forward!

The most wear in the speed control linkage was actually in the "spring pin" holding the "Speed Change Arm" Item 10, on page 5 in the enclosed pdf file, but it was not really that bad. Also the "Neutral Arm" Item 9, page 3 had a worn nylon bushing, and there was metal to metal contact in the forward end.


I am somewhat skeptical whether these couple of worn parts were causing the speed control pedal to stick when switching from forward to reverse, especially since it worked very smoothly when the engine was not running!



Now here is where I started to get new ideas of why the pedal was sticking:

Having read thru all posts on thread " L48 split for HST repair " by rbargeron I found it very useful, and it makes me wonder if the pedal sticking could be caused by excess wear in the "Swash Plate Cradle Bearings" (item 50), which is quite different issue than rbargeron was having?

https://www.tractorbynet.com/forums/kubota-owning-operating/410079-l48-split-hst-repair.html



This is what my F3060 looks like today, and it would be relatively easy to remove the HST for internal inspection:





Testing a new deck (new shell only) couple of years ago:





These are the internal parts of the HST in my F3060 mower:






Just hoping for comments by someone here who may have had similar issues in a tractor, mover or excavator using similar design HST with cradle bearings. This type of mower is basically more or less a small compact tractor, running backwards. I think it is using common parts with many other Kubota's.


PS.
My mower has serial number of just over 10,000 and Kubota replaced HST with a different & better swash plate design at around 20,000 or so.
Pretty sure the new design would be an easy swap to my mower (I have been eyeballing used one for around $1,000)


Below are details of the HST control linkage parts:

 

[rbargeron]

Hi - Very well-detailed post! Your linkage pivot improvements may have solved
the balky motion at the neutral holder - but I did notice something else...
the parts drawing doesn't show them but your cradle bearings may
have a center screw holding them in place? Maybe one of yours is loose and dragging?
Mine were so worn one screw was worn away and in pieces.

Attaching a pic of my new cradle bearings and holder
(looks like your holder is integral with the case)



here are the worn/failed ones:



The crumpled bearing was blocking the swashplate from tilting fully for reverse. Take care, Dick B

 

[arto98607]

Hi - Very well-detailed post! Your linkage pivot improvements may have solved
the balky motion at the neutral holder - but I did notice something else...
the parts drawing doesn't show them but your cradle bearings may
have a center screw holding them in place? Maybe one of yours is loose and dragging?
My were so worn one screw was worn away and in pieces.

Attaching a pic of my new cradle bearings and holder
(looks like your holder is integral with the case) ............zip.............. Take care, Dick B

Thank you for the reply!

It looks like screw holes are visible in the drawing showing the F3060 cradle bearings and I agree it also appears there are no separate holders in the back.

This was a municipal mower for 3600 hours, always driven by hired help before me buying it and I suspect it has also seen lot of back and forth driving and changing direction abruptly.

The cradle bearings are readily available for just over $60 each.





This is what the newer design, after serial No. 20,000 looks like:



There are no cradle bearings and it's probably more reliable after few thousand hours?
This HST unit would possibly bolt right on to the earlier model like mine since the gearboxes it bolts to have the same part numbers.


Anyone here who has done it?

 

[arto98607]

Update:

I have decided to proceed to remove & inspect the HST cradle bearings etc. since my F3060 is already partially disassembled as can be seen in the two photos above in post #1.

It's lot of additional work and there was a big temptation just to put it back together hoping the speed control pedal would no longer stick, but I have my doubts.

There are also couple of other smaller issues that can be better addressed once the engine & transmission have been separated, for example there is some rust in the main frame behind the battery box mounting plate, mainly due to wet grass collecting there and similar but to lesser degree frame rust behind the fuel tank (the rust can be seen clearly in the post #1 photos).

This mower has not likely ever seen snow or salt so the rust must be just from wet grass sitting and decomposing there for many years.


I will keep you posted!



*

 

[jonsstihl]

definitely keep us posted I love these threads where some guys don't hesitate to tear into things.

 

[arto98607]

Update:

F3060 has now been split in two in order to get access to the HST and remove for dismantling & inspection (see post #1 & 4 above).

Quite a few linkages and hydraulic hoses etc. to disconnect - the 16 or so bolts holding the frame together was the easy part!







Here is the HST, ready for little more cleanup & removal:

 

[arto98607]

definitely keep us posted I love these threads where some guys don't hesitate to tear into things.

I have now removed & opened up the HST and based on the initial inspection it looks like the cradle bearings are perfectly fine and had stayed properly in their place.
This HST design does not use screws to hold the cradle bearings in place, instead they sit in grooves that are part of the aluminum housing and are kept from rotating by the housing & pins which are visible in the second photo.

The swash plate cradle bearing side shows very minor wear and I think will be just fine to reuse as is.

Based on the initial inspection it looks like after 3600 hours of use this HST is still in excellent shape and I will just replace all the seals & put in new cradle bearings and reassemble.

It looks to me like the speed control pedal sticking was not caused by anything inside the HST, but was due to wear in couple of locations in the external linkage and a worn loose "spring pin" holding in place the "Speed Change Arm".

 

[rbargeron]

arto:
It was a lot more work, but you will now be confident putting it back together that there are no demons lurking in there!
Great job!. That F3060 is a heluva lawn mower - very nice piece of engineering. Another good example of the machinery Kubota used to build its reputation.

Post some pics when you've got it all back together. Thanks for showing it to us. Dick B

 

[arto98607]

arto:
It was a lot more work, but you will now be confident putting it back together that there are no demons lurking in there!
Great job!. That F3060 is a heluva lawn mower - very nice piece of engineering. Another good example of the machinery Kubota used to build its reputation.

Post some pics when you've got it all back together. Thanks for showing it to us. Dick B

Thank you!

While waiting for the seals etc. to arrive I am going to do something about the way the battery box is attached to the mower frame.
I really don't like the way it's trapping wet grass clippings in-between the frame & battery box!


At minimum I want to make a new battery box, make it easier to remove and be able to clear out any clippings and monitor or repair any signs of future corrosion, but also perhaps figure way to keep the clippings from entering there?
The hydraulic hoses and electrical wire loom being located in-between there are not making it any easier to correct.

There is a similar situation on the opposite side where the fuel tank is attached to the frame, but at least the fuel tank is easy to remove vs. the battery box mounting plate is welded on to the frame.


Current battery box mounting:





Oh well, I will figure out a solution.

 

[rbargeron]

How about a screen box made of 1/4" or 3/8" wire cloth? Easy to form and trim for fit. Bigger clippings would stay outside and little stuff would be easy to blow out with air or water. Can inspect without taking anything apart.

Once a year I give my rigs a brief blast with a pressure washer - works like magic. Have fun, Dick B.