Kubota F series F3680 steering ram fault?

[johncar]

Having recently purchased a used approximately 5 year old F3680 mower I have been going over it servicing and dealing with some of the wear and tear.
One of the things I found was the steering knuckle bushes to have excessive wear which wasn't so noticeable with the machines weight on the wheels but when jacked up it was very obvious they were slopping around.
Anyway ordered all the bits to fix it up like new again.

The chap at kubota spare parts mentioned by the way, that to be aware that there was a recall on the steering ram on these older machines a few years back that perhaps in my case may have contributed to the excessive wear.
The problem was that the steering rams stroke was too long and at full lock either way once the wheels were at their full turning rotation and could move no further if the operator pulled further on the steering wheel the ram would start to try and bend the rear axle and also the chassis where it is all mounted to. This apparently caused some major damage in some cases where complete chassis had to be replaced as they cracked from the fatigue as well as other wear.

I checked mine when I got home and sure enough the rams stroke is indeed too long and when you go beyond full lock you can see the stress and flexing on the rear axle and the chassis and steering knuckles. There being a lot of power in this ram even with only light action on the steering wheel so it is definitely something that requires your urgent attention if you own one and are unaware of the problem and yours hasn't been fixed.

The fix from Kubota is a spacer collar to be installed in the steering ram to limit it's stroke length and readjusted so that the ram does not push or pull in excess of the normal steering travel requirements.
I can't understand why mine wasn't looked at being an ex local government machine so one would think that they would have known through Kubota's records to have it looked at when being serviced. Obviously someone's negligence somewhere which is why I am still reluctant to jump on an airplane at any time for the same reason.

Anyway I am waiting to hear from Kubota to see if they will fix mine or whether I have to do it myself and meanwhile I will be careful not to pull steering wheel into full lock...

 

[jcummins]

Do you know when they corrected? What years are impacted?

 

[johncar]

No sorry, I only have sketchy info at present but I hope to find out more next week when Kubota or the dealer get back to me. The parts guy at the dealer thought it started about 8 years back but wasn't sure when it was corrected with the service notice issued from Kubota. But it could just relate to Australian models. Mine is a bout 5 years old so I would think it would be wise to check your steering ram anyway just to be safe.

Just start the machine and stand beside it with the engine only running. Turn the steering wheel slowly until the steering knuckle on the rear wheels just reaches it's full travel (full lock) in one direction firstly. When you get to this point the steering ram should also be at it's maximum stroke. (it can't push any further)

Then try it in the opposite lock to see if the same applies. If it can not push beyond the full lock due to the ram also being at maximum and minimum stroke then all is good

If the ram still has more stroke left to push further beyond full lock in both directions then you have a problem like mine.

Will post it here if I find out any more.

 

[johncar]

Oh well, shouldn't have been too surprised. Kubota won't fix their steering ram bungle on my machine because yes there was a recall on them a few years back but they say mine is outside of the group of serial numbers that they deemed as a problem.
So I am left with the job and cost of having it corrected. Maybe I was expecting too much but anyway I was quoted around $270 to modify the ram from my local Kubota dealer with the repair kit from Kubota being around $60 retail, the rest being labour to pull the ram apart and fit the spacer. I don't think it would have harmed them to at least supply the part FOC for some good will.

I have been seriously considering buying a new tractor, Kubota M9540 but things like this make me think twice about how well they support their product and machine owners.

Anyhow I have a lathe here at home so I will just machine something up myself to fix it, just would have been easier the other way.

My steering Ram has about a 6" stroke and it only needs to be around 4" so I gather it will just need a spacer fitted to the shaft to limit its travel by approx 2" and then readjust the position of the ram to centre it again. I might even just make an external spacer out of nylon or similar which should do the job.

Although its not something that should affect most people out there I will post a pic when I have done it for anyone interested..

It is just the that damage has the potential to be quite catastrophic if gone unchecked.

 

[1bush2hog]

Thanks for the info Johncar. I recently purchased a used F3680 too and am very interested in any updates you post

 

[Rip]

Hi JohnCar, I have been traveling so have not been on the forum for a bit but have a used 2009 council F-2880 down in Tassie that I wonder if it could have similar issue? I did have to get the steer axle repaired last year with new bushings and Rt side knuckle that could have been pushed to failure if the steering ram was often trying to over-travel it. Any idea if problem could apply to my machine?

I am in the States for a bit, so will not be able to inspect the unit anytime soon. Thanks to John Thomas on this forum for helping me choose this unit.....is the perfect machine for our 4 acres of flat/steep/very-steep paddock.

Cheers, Rip

 

[johncar]

Hi Rip,
I sort of covered what I did about my ram over stroke in the Height adjustment thread, but yeah mine was definitely about 48mm too much travel.
I just thought that my steering knuckles were worn from normal use but is seems more likely that they were assisted by an overshooting steering ram. I am hoping that there is no other damage to mine but I have heard that there were some major damaged machines which would probably depend on operator habits I guess. When I replaced the new bushes and pins and put it back together like new again I noticed that when I steered to full lock in either direction that the whole back axle was being flexed once the wheels hit full lock and knew it wasn't good or correct.

I contacted Kubota Australia via my local dealer and was told that the steering ram problem involved a group of serial numbers which were earlier than my machine which is ser#14472 by the way. I can't say for sure but I think that the dealer mentioned that it involved serial numbers 12xxx and earlier.

Anyhow mine definitely was no good and neither were Kubota Aust about it when I asked them if they would do the modification it being subject to a recall or service notice and they said no... I was quoted about $270 by the way for the dealer to supply and fit the kit plus I had to get the machine down to them and back about 100kms each way.
I could have probably asked them to supply the kit only and done it myself but I am happy enough with my back yard repair for now.

It is pretty easy to check your machine. Just jack up the back axle and steer lock to lock with the engine running (carefully!). The ram should max out at the same time or slightly before the right hand wheel hits it's stop adjustments. (the left hand wheel has no lock to lock stops but relies on the right hand wheel via the rear steering tie rod)
If the wheels hit their stop adjustments and the ram still has more travel left then I would strongly advise to fix it.

 

[Rip]

John, I will definitely check the steering out when I get back.....am in the States now and a mate is mowing with my machine as needed to keep things under control. I do not know my serial # nor if the 2880 series would be in the same sequence as the 3680.

BTW, may want to re-size your photos as they come through quite large when clicked-on.

Cheers, Rip

 

[johncar]

OK thanks for the tip on the photos. Strangely they appear Ok on my computer. Do you know what the ideal size is for this site??

 

[fejox]

does anyone know of the part number for this steering stop kit?? it would be great! thanks

Having recently purchased a used approximately 5 year old F3680 mower I have been going over it servicing and dealing with some of the wear and tear.
One of the things I found was the steering knuckle bushes to have excessive wear which wasn't so noticeable with the machines weight on the wheels but when jacked up it was very obvious they were slopping around.
Anyway ordered all the bits to fix it up like new again.

The chap at kubota spare parts mentioned by the way, that to be aware that there was a recall on the steering ram on these older machines a few years back that perhaps in my case may have contributed to the excessive wear.
The problem was that the steering rams stroke was too long and at full lock either way once the wheels were at their full turning rotation and could move no further if the operator pulled further on the steering wheel the ram would start to try and bend the rear axle and also the chassis where it is all mounted to. This apparently caused some major damage in some cases where complete chassis had to be replaced as they cracked from the fatigue as well as other wear.

I checked mine when I got home and sure enough the rams stroke is indeed too long and when you go beyond full lock you can see the stress and flexing on the rear axle and the chassis and steering knuckles. There being a lot of power in this ram even with only light action on the steering wheel so it is definitely something that requires your urgent attention if you own one and are unaware of the problem and yours hasn't been fixed.

The fix from Kubota is a spacer collar to be installed in the steering ram to limit it's stroke length and readjusted so that the ram does not push or pull in excess of the normal steering travel requirements.
I can't understand why mine wasn't looked at being an ex local government machine so one would think that they would have known through Kubota's records to have it looked at when being serviced. Obviously someone's negligence somewhere which is why I am still reluctant to jump on an airplane at any time for the same reason.

Anyway I am waiting to hear from Kubota to see if they will fix mine or whether I have to do it myself and meanwhile I will be careful not to pull steering wheel into full lock...