F3680 steering

THurston63

New member
Lifetime Member

Equipment
F 3680, MX 5000
Jan 30, 2017
16
0
0
Louisville, KY
I am hoping to find some help with advice on my F3680 steering. After mowing for about 3 hours the steering on my mower all but went out. The steering wheel turned normally, but there was no or very little movement/turning of the rear tires. After letting the mower sit for a day, the steering appears to work normally with no apparent leaks in the lines that I can see.

According to the shop manual the steering system consists of the oil strainer, hydraulic pump, flow priority valve, steering controller, and steering cylinder. In accordance with the troubleshooting guide - if the mower "can not be steered" the problem is a faulty steering controller or broken hose. What I am not sure of is what does "can not be steered" mean exactly. Does it mean the steering wheel turns but the tires do not move (my problem)? I really have no definite indication of what may be causing the problem, and at this point it appears to be an intermittent one.

I am trying to see if anyone has experienced this before that can help provide some troubleshooting suggestions that will help me define the specific problem or malfunctioning part. I do not wish to "shotgun" replace parts until the problem is fixed, especially since a new power steering controller is over $900.
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,306
4,856
113
Sandpoint, ID
In this case the WSM is not of much help.
but here is a link to download a copy if you don't already have it.
www.kubota.cz/data/manualy/f-80-wsm-en.pdf

If the lift portion of the unit is working then the hydraulic pump is working.
Fluid levels in this unit are very important, also if the pump system is sucking air that will effect steering first.
Look at all the hoses and lines for wet spots as air leaks will not leak like a pressure side leak.

If steering gradually gets weaker and slower in the turning,then the most likely cause would be bad internal seals in the steering cylinder.
That could be tested by removing one line and slowly steering the unit in the direction, you will get fluid out until it reaches the end of the throw then fluid flow should stop if it does not then you have bad internal seals.
 

THurston63

New member
Lifetime Member

Equipment
F 3680, MX 5000
Jan 30, 2017
16
0
0
Louisville, KY
Thanks so much for the reply. Transmission/hydraulic fluid level is GTG, with no signs of leaking (unless I am just missing it). I get the impression that something is just starting to fail or a minuscule leak in a hose that needs to manifest itself before it will be apparent what is actually wrong. Right now I am going to try your suggestion with the cylinder and use it until the problem shows itself again. Then I hope I can figure out exactly what has failed.