Bobcat T190 hydraulic failure

[Philosaw]

I have a t190 with 2400 hrs. It's a turbo/high flow. It's been well maintained by myself and has really been pretty reliable. I just moved to a new job and after about 1 hour of work the hydraulics started to slow. This includes bucket lift, tilt and clamshell. The drive is fine. We parked it and checked the fluid which showed full. We returned the next day and the fluid showed low, but it took less than a gallon to top it off. We started it up and it worked fine for about an hour and went back to barely functioning, that is, unless the engine is at high rpm's it won't raise the bucket. I brought it home and my bobcat shop manual says bad pump, and shows a parts breakdown of a 2 gear pump. My bobcat dealer say it doesn't have a pump but rather a hydraulic control and didn't offer much else in the way of info. I understand that these things are pretty damn technical, but it seem like some of you guys are pretty savvy. Any leads would be appreciated.

 

[mikebramel]

I would be looking into the pump or main relief

 

[Philosaw]

I have been unable to locate a "pump" as I would expect it to look. What I see is a long rectangular box with a valve and solenoids on the top. This is what I assume the dealer is calling the controller. For some reason my Bobcat shop manual doesn't show this, even thought it references my serial number. I don't get it.

 

[willie59]

Welcome to HEF Philosaw. :drinkup

Is your machine standard controls (foot pedals for loader, hand levers for drive), or Advanced Hand Controls (loader and drive controlled by drive levers), or Selectable Joystick machine?


I don't know what the heck Bobcat is talking about, but a T190, like any other Bobcat, it has the hydrostat drive pumps, and piggy back from the drive pumps will be the charge pump (work equipment [gear] pump), and if it's a high flow machine there will be an additional gear pump that piggybacks off of the charge pump.

 

[Philosaw]

Thanks for replying. Mine is the std. foot controls. My parts breakdown shows what you say, but I sure can't see it.

 

[Philosaw]

Ok, I'm stupid! I see the pump and now need to figure out if it's bad.

 

[crewchief888]

sounds like you have a weak hyd pump.

connect a flowmeter to the aux couplers, warm the oil to 130*F and see what your flow is...


:drinkup

 

[Philosaw]

Now that I know what I'm looking at, I'm going to start with the belt adjustment because right when I was starting loading it up to bring back to the shop, I remember hearing belt squeal and felt a little loss of drive power. That's first thing tomorrow, then it'll be the flow check. Thanks for your help

 

[willie59]

If the drive belt doesn't have enough tension you will typically feel a loss of drive power under a hard push or drive load. It'll fall flat on it's nose until you let off the sticks and regroup.

 

[Philosaw]

I'm probably barking up the wrong tree, but I always start at the beginning and work my way out. First belt then flow test then pressure test, then r&r.

 

[Philosaw]

I had the pressure tested at the dealer and got a report of 1800 lbs, which is 500 below normal operating pressure and less than the 3200 max. I was also told that the control valve solenoid was bad. My thought is that 1800 lbs should be enough to allow the hydraulics to function though not with as much power. Right now, I have to rev the engine up quite high to raise the arms. With that thought and no knowledge of what function the control valve solenoid has, I replaced it since it was fairly inexpensive. After replacing it the hydraulic functions the same. So, I have removed the hydraulic pump and will replace, but I have no confidence that this is the culprit. I read in the manual that there are two filter screens located below the control valve and wonder if they could be the problem, but I can't see them and it appears it would take removal of most if not all of the hydraulic lines from the valve to get at it. Is my reasoning correct, or am I totally off?

 

[crewchief888]

what was the hyd pump flow?


:drinkup

 

[Philosaw]

Unfortunately my $380 didn't get me a flow test, but they did tell me I needed a new headlight!