A300 Left Drives Stopped Working

[Bobcat-A300]

I was using my Bobcat A300 and out of nowhere the left side just stopped moving forward. The only movement I get now is in reverse and even that feels weak.

Before this happened, the left side was already acting off. It was slower than the right side and had a delay when moving.

I took off the left hydrostatic pump controller to check it out and noticed the control spool is not staying centered like it’s supposed to. I can move it to center by hand, but it just slides right back out. When I pull it to center I also hear a suction or vacuum type sound coming from it.

The machine has around 4000 hours on it, and since I bought it it’s been running good for the last 100 hours I’ve used it with no major issues until now. The only thing I’ve had to replace so far were all 4 hydraulic cylinder seals on the all wheel steer system.

I’m also planning on changing the two case drain filters to see if that makes any difference.

I’m not sure if this is a bad centering spring behind the spool, something internal in the pump, or maybe some kind of pressure issue. I haven’t opened up the bore plug yet to check the spring.

Has anyone dealt with this before? What would cause the spool not to stay centered like that? And is that suction sound normal or a sign something is wrong inside the pump?

Trying to figure out if this is something fixable or if I’m looking at replacing the pump.

Any help would really be appreciated.

 

[ETuso]

Were you able to find a solution? We’ve got a A300 that is currently having the same issue.

 

[Bobcat-A300]

Were you able to find a solution? We’ve got a A300 that is currently having the same issue.

No not yet, I think the control spool is ok and is meant to slide to one side because there is only one spring pushing it, I’m going to swap the left and right hydrostatic pump controller and see if the issue goes to the opposite side of the bobcat

 

[River Fluid Power]

What you describe happening under the removed controller is absolutely normal. The spring pushes it to the side. The suction sound is good as well. Please be careful not to introduce dirt into the pump. You can swap the controllers to troubleshoot, but keep in mind that has the potential to cross contaminate. There are plastic manual override levers on the controls that can help troubleshoot as well. Get the tires off the ground before trying that. I can get you reman and new controls if you need. I have very competitive pricing on them.

 

[Bobcat-A300]

What you describe happening under the removed controller is absolutely normal. The spring pushes it to the side. The suction sound is good as well. Please be careful not to introduce dirt into the pump. You can swap the controllers to troubleshoot, but keep in mind that has the potential to cross contaminate. There are plastic manual override levers on the controls that can help troubleshoot as well. Get the tires off the ground before trying that. I can get you reman and new controls if you need. I have very competitive pricing on them.

Ok thanks im going to clean the area and swap the controllers and test it out.
Is it possible to test the controller if I remove it and give it 12v with a multimeter? Or would that damage the controller.

 

[River Fluid Power]

Ok thanks im going to clean the area and swap the controllers and test it out.
Is it possible to test the controller if I remove it and give it 12v with a multimeter? Or would that damage the controller.

I don’t think it will hurt to apply the full 12VDC for a few seconds.

 

[Bobcat-A300]

I don’t think it will hurt to apply the full 12VDC for a few seconds.

I was swapping the pump controllers today and I noticed the plastic override control was broken and leaking some kind of oil.
The controller that was working fine looks good. Most likely going to need a replacement?

 

[River Fluid Power]

I was swapping the pump controllers today and I noticed the plastic override control was broken and leaking some kind of oil.
The controller that was working fine looks good. Most likely going to need a replacement?

I was swapping the pump controllers today and I noticed the plastic override control was broken and leaking some kind of oil.
The controller that was working fine looks good. Most likely going to need a replacement?

Chances are good, yes. The oil leaking out is glycerin. It protects the armature inside the plastic case from moisture. Were you able to see the issue follow the controls when you swapped them?

 

[Bobcat-A300]

Chances are good, yes. The oil leaking out is glycerin. It protects the armature inside the plastic case from moisture. Were you able to see the issue follow the controls when you swapped them?

Yes I turned on the bobcat and now the right side started creeping forward slowly, then the machine turned itself off. un-commanded right wheel speed error

 

[River Fluid Power]

Yes I turned on the bobcat and now the right side started creeping forward slowly, then the machine turned itself off. un-commanded right wheel speed error

A replacement control should do the trick. We offer new and reman. You can find them on our website under 6678339 and 6678339R. You can also send us yours for repair. riverfluidpower.com

 

[Bobcat-A300]

What is the price range and time for a rebuild? I can ship.

 

[River Fluid Power]

What is the price range and time for a rebuild? I can ship.

$1050-$1500

 

[River Fluid Power]

$1050-$1500

2-3 weeks for the rebuild.

 

[Bobcat-A300]

I have two controllers that do not work, would I be able to give you two core returns and purchase 1 rebuilt controller?

 

[River Fluid Power]

I have two controllers that do not work, would I be able to give you two core returns and purchase 1 rebuilt controller?

I can accept one as a full core for a reman and offer $100 for the extra core.

 

[JamQwe56]

If it was already slow and lagging before it failed, that usually points to wear inside the system. The spool not staying centered makes me think the centering spring could be worn or broken, or something is sticking internally.
That suction/vacuum sound doesn’t sound right either — could be internal leakage or pressure issues in the pump.
Good idea to change the case drain filters, but I’d also check the spring behind the bore plug first. If that’s fine, then it might be internal pump wear, especially at 4000 hours.

 

[ward]

I was using my Bobcat A300 and out of nowhere the left side just stopped moving forward. The only movement I get now is in reverse and even that feels weak.

Before this happened, the left side was already acting off. It was slower than the right side and had a delay when moving.

I took off the left hydrostatic pump controller to check it out and noticed the control spool is not staying centered like it’s supposed to. I can move it to center by hand, but it just slides right back out. When I pull it to center I also hear a suction or vacuum type sound coming from it.

The machine has around 4000 hours on it, and since I bought it it’s been running good for the last 100 hours I’ve used it with no major issues until now. The only thing I’ve had to replace so far were all 4 hydraulic cylinder seals on the all wheel steer system.

I’m also planning on changing the two case drain filters to see if that makes any difference.

I’m not sure if this is a bad centering spring behind the spool, something internal in the pump, or maybe some kind of pressure issue. I haven’t opened up the bore plug yet to check the spring.

Has anyone dealt with this before? What would cause the spool not to stay centered like that? And is that suction sound normal or a sign something is wrong inside the pump?

Trying to figure out if this is something fixable or if I’m looking at replacing the pump.

Any help would really be appreciated.View attachment 10847View attachment 10844

If you note YOU are introducing dirt in to the system, a sytem that has a pump that looks like a cylinder on a rolver that is loaded with pistons in that cylinder have no seals on them because the oil is the seal as the tolarences are that close, even microscopic dirt can score either the cylinder or pistons cause it to bypass internally.
If I ownd that machine I and I saw it opened like that I would stop all work clean and replace the controler and get that area cleand up , then pull that pump for disassemble and cleaning then reinstall it, when you take hydrostatic parts apart in the field you want the area as clean as what the shop manual shows, in their pictures, they dont show dirt falling inside the pump.
If for some reason I have been unclear when I say clean, you can server your food on top of it you can use it as your plate, I would not start that machine until that pump has been removed and disassembled, I know other are being polite by not saying any thing, however every real mechanic that has worked on hydrostatic systems are cringing right now because you are about to wipe out that pump, oh it may get by for a while but that pupm begins a quick death by dirt contamination that causes it to just self destruct.