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Old 08-04-2018, 11:11 PM
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Default Bobcat Skid-steer movement/steering issues

Ok so my bobcat has some issues with steering I'm pretty sure it is in the transmissions and not the hydraulic pump due to it will lift a load with no issue but it will not climb a hill or load on trailer and has slow to non responsive steering but I find my self second guessing my diagnosis now its an old model and has seen lots of use an has always been a strong machine all fluids were changed and it made no difference

I am thinking it is in the drive trans where the problem lays but like I was saying I find my self second guessing and think I might be missing something any ideas or anyone had similar issues as I'm thinking I'm gonna have to replace the drive hydraulics in order to solve my issues
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Old 08-04-2018, 11:15 PM
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What make and model is it?
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Old 08-05-2018, 05:23 AM
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I am not sure about bob cats setup, but in my Gehl skid loader, there are three separate pumps. One pump for each side set of wheels, and the third pump for the lift boom. Each pump is matched to the drive motor, and my boss told me that if there is something wrong with the pump, probably would have to rebuild/ replace both pump and motor, due to them being a separate independent system , although they both pull oil from same reservoir tank.

I would probably check linkages. Mine were wore pretty bad, and the shafts to the pump had keys that allowed a lot of play. You might not be getting enough range of motion to fully engage the pump on the controls. I was using a friends “bobcat” couple weeks ago, and it seemed his controls were wore out too. I know if I pushed both sticks all the way forward, one side would definitely turn faster than the other and not go straight.


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Old 08-05-2018, 05:30 AM
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I am not sure about bob cats setup, but in my Gehl skid loader, there are three separate pumps. One pump for each side set of wheels, and the third pump for the lift boom. Each pump is matched to the drive motor, and my boss told me that if there is something wrong with the pump, probably would have to rebuild/ replace both pump and motor, due to them being a separate independent system , although they both pull oil from same reservoir tank.

I would probably check linkages. Mine were wore pretty bad, and the shafts to the pump had keys that allowed a lot of play. You might not be getting enough range of motion to fully engage the pump on the controls. I was using a friends “bobcat” couple weeks ago, and it seemed his controls were wore out too. I know if I pushed both sticks all the way forward, one side would definitely turn faster than the other and not go straight.


Now, my case uniloader skid loader has a different setup for driving the wheels. It is done with mechanical clutch packs. And had a big snowmobile type drive belt that could be changed with hydraulic pressure to change drive speeds. Once I learned that, I would change the speed more, and learned why the previous owner never told me about that lever. The clutch came apart one time, and it was not going to go anywhere til it was fixed. He also then warned me against changing the speed because the clutch packs were weak, and parts were either non existent, or very expensive. If I ever get the motor rebuilt, I will be finding out for myself. That project has been sitting on a bench in my shop for about 12 years now. I am a little slow finishing most of my projects.

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Old 08-05-2018, 03:23 PM
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What make and model is it?

It a 1996 Clark 630
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Old 08-05-2018, 03:33 PM
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I am getting a lot of hi pitched noise when I try to turn in any direction and have no push of climb power but on flat surface it will go forward and backward with ease the bucket will lift and responds fast
so it is sort of throwing me off I'm wondering if part of the drive motors are weak and getting internal blow by or if its a control valve issue or linkage as they are fairly wore 1 control arm when going forward is about 4-6 inches in front of the other when going forward but I don't think that's the issue couldn't be so simple in my world
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Old 08-05-2018, 03:49 PM
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It should have hydraulic motors on each side for driving wheels I am guessing then, being a newer year model than I have. Maybe something to check is make sure the pumps are getting the fluid needed from reservoir tank and there is no restriction in. Supply line. Try to keep it simple things to rule out before you actually start taking the hydraulic pumps/ motors out.


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Old 08-05-2018, 04:08 PM
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I’m not familiar with your model but would guess it’s going to be similar to my 2005 463 machine.

Given the the fault is common to both sides it highly unlikely to be a problem with pumps and motors as they are independent systems on each side.

As has been suggested check the oil flow into the pumps. Is there a strainer that might be blocked?

On my machine the pumps are driven by a big v belt from the flywheel. Does your machine have a similar set up? If so have you checked the belt condition and tension.

Just a few easy things to check first.

Rob


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Old 08-05-2018, 07:28 PM
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Quote:
Originally Posted by MetalWolf View Post
I am getting a lot of hi pitched noise when I try to turn in any direction and have no push of climb power but on flat surface it will go forward and backward with ease the bucket will lift and responds fast
so it is sort of throwing me off I'm wondering if part of the drive motors are weak and getting internal blow by or if its a control valve issue or linkage as they are fairly wore 1 control arm when going forward is about 4-6 inches in front of the other when going forward but I don't think that's the issue couldn't be so simple in my world
Pull your filter element and examine. Might have to cut it open if it’s a canister type. If you see glitter, chunks or anything that’s not hydraulic oil there’s your issue.

If the fluid level is good there three things to cause the whine you hear, its either the pumps or motors bypassing high pressure fluid or They could also be cavatating, check for cracks or splits on the suction lines.
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Old 08-05-2018, 07:43 PM
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Later in the week ill be pulling the pans and cage off it so I can see what's going on with lines and motors hate for it to be the drive motors or main pump. hope I don't find metal in the filter
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