T-200 with Hydraulics Always Engaged

[Jungle T-200]

Hello, I've got a T-200 Turbo High Flow stuck in a remote mountainous area of Costa Rica. The Deutz engine runs great typically but now seems to be engaged into the hydraulics so much that while I can turn it over, it won't start due to the load. Those symptoms started out ever so slightly where I could fiddle with the two control levers and get the engine running, though now it won't even start. I was able to get the engine started momentarily yesterday but suddenly black smoke and an overburdening of the engine seems to stall it out. It makes no difference if the seat bar is up or down, the engine still has the same workload on it. With the bar down there is a light "on" in the BICS panel and I can push the green button and have all the other lights come on, until it stalls out, and that at a fast idle. The hydraulic fluid is up though I do have a dripping lift cylinder seal. Something is causing the machine to engage the hydraulics all the time thus not allowing the engine to operate detached from the hydraulic load. The only Bobcat dealer in the country has now been deemed "unauthorized" and taken off Bobcat's list of dealers, while no Bobcat service departments in the states really want to talk with me. I hope someone out there can point me in the right direction on what to easily test for.

 

[Bobcatdan]

Sounds like an aux control vavle stem is stuck. Flip the cab. On top of the vavle, one in front and one back are the vavles that control the aux main spool vavle. One is most likely jammed open with a tiny piece of crap. You could try unplugging them to make sure there is no electrical short causing them to stay on. You can try removing them and cleaning them. Personally I never had luck with that. If you are really in a pinch, rig up a jumper hose to plug into the aux couplers to make a free flowing loop for the circuit. That should allow you to start and move the unit.

 

[Jungle T-200]

Sounds like an aux control vavle stem is stuck. Flip the cab. On top of the vavle, one in front and one back are the vavles that control the aux main spool vavle. One is most likely jammed open with a tiny piece of crap. You could try unplugging them to make sure there is no electrical short causing them to stay on. You can try removing them and cleaning them. Personally I never had luck with that. If you are really in a pinch, rig up a jumper hose to plug into the aux couplers to make a free flowing loop for the circuit. That should allow you to start and move the unit.

Bobcatdan, Thank you so much for supplying me with the information on the front and back "aux control valves". Since receiving your information, I have been doing my best to try to identify them positively. Its well after dark here now but I do have the service manual opened to "rear auxiliary diverter valve". I cannot find any mention of the "front" valve you wrote of? (There is information on the auxiliary pressure release (accumulator)" though.) I will make every attempt to locate the front valve tomorrow morning and clean them both, and also get a multi-meter on both coils to check them. Thank you. Is there a particular name for the front valve that I will recognize in the manual? As for making a "jumper hose", please explain a bit more on what you are suggesting. I can buy some hydraulic hoses and parts about an hour and a half drive from here, one way, when they choose to be open.

 

[Bobcatdan]

Bobcatdan, Thank you so much for supplying me with the information on the front and back "aux control valves". Since receiving your information, I have been doing my best to try to identify them positively. Its well after dark here now but I do have the service manual opened to "rear auxiliary diverter valve". I cannot find any mention of the "front" valve you wrote of? (There is information on the auxiliary pressure release (accumulator)" though.) I will make every attempt to locate the front valve tomorrow morning and clean them both, and also get a multi-meter on both coils to check them. Thank you. Is there a particular name for the front valve that I will recognize in the manual? As for making a "jumper hose", please explain a bit more on what you are suggesting. I can buy some hydraulic hoses and parts about an hour and a half drive from here, one way, when they choose to be open.

As for the vavle, the aux works like this. Two electric coils mounted to the main control vavle magneticly move a small vavle inside of the "stem" the coil slides over. When the stem is open, it meters oil to hydraulicly shift the main aux vavle. If the stem is stuck open, the aux vavle is constantly being pushed open. With nothing coupled to the aux couplers, the system deadheads. You want to be looking at the main control vavle on the right side of the machine under the cab. Don't worry about the rear diverter, more then likely the machine doesn't have one. As for a jumper hose, you would need a male and a female flat face coupler to match the ones on your machine. Then what ever hose and fittings you need to connect the two. In the off chance you have an auger for the unit, easier said then done, put the auger on it to complete the loop.

 

[Jungle T-200]

As for the vavle, the aux works like this. Two electric coils mounted to the main control vavle magneticly move a small vavle inside of the "stem" the coil slides over. When the stem is open, it meters oil to hydraulicly shift the main aux vavle. If the stem is stuck open, the aux vavle is constantly being pushed open. With nothing coupled to the aux couplers, the system deadheads. You want to be looking at the main control vavle on the right side of the machine under the cab. Don't worry about the rear diverter, more then likely the machine doesn't have one. As for a jumper hose, you would need a male and a female flat face coupler to match the ones on your machine. Then what ever hose and fittings you need to connect the two. In the off chance you have an auger for the unit, easier said then done, put the auger on it to complete the loop.

Bobcatdan, Thank you for again explaining more about the the valves and how they work. I have had my head under the seat and believe the main valve you are referring to is located on the right side (facing forward toward the bucket while in the operator's seat) and has the solenoid on top of the valve. The solenoid has an aluminum tag on it that says, "10 volt coil for proportional control only". If that is the one, I will remove both the coil and inner valve assembly tomorrow to see what it looks like. Should I check the coil with a multi-meter too for ten volts and a certain ohm range? When you speak of an "auger unit", are you referring to a post hole auger or something else? I apologize for being so unfamiliar with all you have written about pertaining to the T-200. It isn't something I have spent a lot of time working on, yet. Don't know what I would do without you lending a hand. Thank you.

 

[Bobcatdan]

Bobcatdan, Thank you for again explaining more about the the valves and how they work. I have had my head under the seat and believe the main valve you are referring to is located on the right side (facing forward toward the bucket while in the operator's seat) and has the solenoid on top of the valve. The solenoid has an aluminum tag on it that says, "10 volt coil for proportional control only". If that is the one, I will remove both the coil and inner valve assembly tomorrow to see what it looks like. Should I check the coil with a multi-meter too for ten volts and a certain ohm range? When you speak of an "auger unit", are you referring to a post hole auger or something else? I apologize for being so unfamiliar with all you have written about pertaining to the T-200. It isn't something I have spent a lot of time working on, yet. Don't know what I would do without you lending a hand. Thank you.

There are two of the those coils, make sure you check the other one two. Yes when I say auger, that is a post hole digger.

 

[Jungle T-200]

There are two of the those coils, make sure you check the other one two. Yes when I say auger, that is a post hole digger.

Bobcatdan, I removed the top coil and valve, and examined it. The ohm reading checks out for the coil. When placed over the valve stem, it draws the valve back just a bit but I cannot determine the proper amount of travel it is suppose to be drawn back. When I force air through the bottom of the valve, I can feel it coming out above on the sides, I imagine indicating something remains holding it open. If there were only a way I could get parts here, I would have a new one already installed. Bobcat still hasn't gotten back to me on how to obtain parts in Costa Rica now that they have no authorized dealers here.

 

[Bobcatdan]

Bobcatdan, I removed the top coil and valve, and examined it. The ohm reading checks out for the coil. When placed over the valve stem, it draws the valve back just a bit but I cannot determine the proper amount of travel it is suppose to be drawn back. When I force air through the bottom of the valve, I can feel it coming out above on the sides, I imagine indicating something remains holding it open. If there were only a way I could get parts here, I would have a new one already installed. Bobcat still hasn't gotten back to me on how to obtain parts in Costa Rica now that they have no authorized dealers here.

Did you pull the other one also, there are two of them.

 

[Jungle T-200]

Did you pull the other one also, there are two of them.

Bobcatdan, I did pull both of the "10 volt" solenoids today, along with both of the corresponding valves. Both screens were as clean as a whistle and both solenoids checkout on the ohm test and when hitched up remotely to 10 volts. I observed the amount of throw for each valve inner piston and they both appear to be the same. Both under power (activated with10 volts) and without any power (shut off), I blew each valve out with compressed air and reassembled the units. Then when attempting to start the Bobcat, it still wouldn't start due to the load that remains on it. Too, the machine wanted to turn with the seat bar up. So I lowered the seat bar and clicked on the Bics system, so three of the four lights were on, and then turned the key to start it, this taking some of the pressure (hydraulic load) off the engine. It ran a bit, actually just enough for me to raise the lift arms before it stalled. (This will enable me to change the lift cylinder seal with the arms up). Sadly, blowing out the two valves did nothing to solve the problem. The machine is still engaged some how, fighting itself under a tremendous hydraulic load. I also noticed a third solenoid on the same control block. It is lower and faces the hydraulic tank (inside). Is this something I should consider cleaning and testing as well? When I do fiddle with the two joy stick handles, it seems to lessen the load a little, but not enough to allow it to start.