F3680 - Steering very jerky and slow. How do you bleed it?

[Viffer]

I recently bought this mower secondhand and used it for about 2 hours before I lost drive and steering. I thought it was due to lack of hydraulic oil which probably allowed air into the system. I had a full service but went to collect it today to find the steering still is not responsive and juddery, although the drive seemed fine.

The WSM says this could be due to air in the steering system and you should bleed it. Unfortunately I can find no details on bleeding the steering system anywhere.

Any help appreciated.

 

[JOHNTHOMAS]

When my F3080 was new it sometimes would not steer. Thw steering wheel would spin but no wheel turning and then it would clear up and turn right. Look thru my old posts and you can see the start, middle and end of the process as I went thru it till it was fixed with no problems for the last 2 years mowing season.

 

[boggen]

assuming you have 2 hyd cylinders that are used to turn the wheels....

get the front wheels off the ground.
fully turn wheels to the left till they stop
then...
fully turn wheels to the right till they stop

do above a few times.

when a hyd cylinder is fully extended, and then fully contracted. and then repeated a few times. it causes pretty much all the hyd oil in each side of the hyd cylinder to get pushed out and then replaced with new hyd oil.

as far getting the front wheels off the ground. it is an attempt to keep the "air from becoming compressed more in attempt to turn wheels on hard surface that are not rolling over the ground.

once majorty of the air is out of the system (see above). and you keep the oil level up for power steering. any remaining air should work its way out from normal operation of tractor.

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make sure you are checking correct "oil"

some tractors have a "power steering pump" were you might add oil directly to the pump, (some place up and around engine most likely connected to "fan belt" on engine.

some tractors might have regular FEL (front end loader) and power steering together, and just one place to check hyd oil.

i don't know your specific tractor so all i can say is above.

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many tractors use same oil for power steering as hyd oil for FEL (front end loader / rear hyd remotes)

then ya get others that use different oil types all together.

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there maybe something wrong with the power steering motor ((what the steering wheel attaches to)) there are valves in it, that directs oil from pump. and decides how much and were to put the oil. perhaps the steering wheel motor is bad / seals bad.

 

[JOHNTHOMAS]

assuming you have 2 hyd cylinders that are used to turn the wheels....

get the front wheels off the ground.
fully turn wheels to the left till they stop
then...
fully turn wheels to the right till they stop

do above a few times.

when a hyd cylinder is fully extended, and then fully contracted. and then repeated a few times. it causes pretty much all the hyd oil in each side of the hyd cylinder to get pushed out and then replaced with new hyd oil.

as far getting the front wheels off the ground. it is an attempt to keep the "air from becoming compressed more in attempt to turn wheels on hard surface that are not rolling over the ground.

once majorty of the air is out of the system (see above). and you keep the oil level up for power steering. any remaining air should work its way out from normal operation of tractor.

==============
make sure you are checking correct "oil"

some tractors have a "power steering pump" were you might add oil directly to the pump, (some place up and around engine most likely connected to "fan belt" on engine.

some tractors might have regular FEL (front end loader) and power steering together, and just one place to check hyd oil.

i don't know your specific tractor so all i can say is above.

=============
many tractors use same oil for power steering as hyd oil for FEL (front end loader / rear hyd remotes)

then ya get others that use different oil types all together.

==============
==============
there maybe something wrong with the power steering motor ((what the steering wheel attaches to)) there are valves in it, that directs oil from pump. and decides how much and were to put the oil. perhaps the steering wheel motor is bad / seals bad.

It steers with rear wheels and only has one steering rod. All hyd fluid is in one spot.
Sometimes generec answers don't work.

 

[boggen]

It steers with rear wheels and only has one steering rod. All hyd fluid is in one spot.
Sometimes generec answers don't work.

rear wheels front wheels *shrugs*... goto kubota.com -> parts, type in info... looking at "steering" and "hydraulic" diagrams. it still has all the same generic stuff. steering wheel motor, hydraulic cylinder, the entire unit looks like it has a single hyd system for everything one spot to check/fill.

lift rear end to get steering wheels off of ground. and use steering wheel to go fully left, then fully right. a few times. and that should bleed out majority if not all air out. any remaining air will bleed out through normal use.

there is no undo a hose. and do something till ya get oil out of a line. ya just fully extend / fully contract. and air works it's way out of the system.

 

[Viffer]

Thanks a lot guys. It has been sent on to a hydraulic specialist. I called Kubota Ireland (IrishGrassMachinery) and one of their engineers spoke with me. It seems that bleeding is as you say lock to lock a couple of times while checking hydraulic oil level. It was not that unfortunately. From there it could be a seal in the steering ram. Or a seal in the steering control cylinder just under the steering wheel. It's unlikely the be the hydraulic pump as the deck lift is on the same run and working fine.

 

[boggen]

to test if seal/s are bad in hyd cylinder....

lift steering wheels off ground.
turn wheels fully left till lock
undoing one of the hyd hoses going to the cylinder. ((you want the one that is causing hyd cylinder to fully turn wheels left attached.)) disconnect other hose.
turn on machine, and turn wheels left with steering wheel.... if hyd oil starts coming out of hyd cylinder then seals are bad in it.

turn off machine
reconnect hyd hose.
turn machine back on
turn wheels lock to lock a few times (to get most of air out)

this time turn wheels fully right.
disconnect hyd hose going to cylinder that is not turning wheels fully right
turn on machine.
turn on machine, and turn wheels right with steering wheel.... if hyd oil starts coming out of hyd cylinder then seals are bad in it.

turn off machine
reconnect hyd hose
turn machine back on
turn wheels lock to lock a few times (to get most of air out)

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a tractor dealer more likely has a way to test the cylinder without all the "blah blah" above. if you just pull the cylinder and take it into them.

a tractor dealer most likely has extra pressure gauges to put in line to test out the steering motor (what the steer wheel connects to) to see if seal/s are bad. they may use pressure gauges to test hyd cylinder as well.

 

[Viffer]

Seems the hydraulic pump is gone. Someone had already been at it and put the pressure up to 3000 psi instead of the 1500-1600psi it should be and there was still no oil flow. So another €500 for a new one fitted. Should have it back in a week.