Hi, New to the forum and of course have a problem and need help. I have a 05 t250 that operates perfectly from cold start for about 5-6 min, then when using the tilt action (either foward or back) the hydraulics will pulse rapidly trying to find center. It will continue to pulse until its fully extended or retracted. Pulsing gets more pronounced when RPM is increased. It does this on both controls, joystick and foot pedal. The lift hydraulics are affected when the tilt acts up but stops when tilt cyl's. are extended or retracted. But the lift function works properly w/no pulsing otherwise. Probably pulsing from pressure spikes generated by the tilt problem. Have changed both actuators on the valve body, done the calibration by the service manual procedure, checked all ground wires for bad connections and pulled all connectors under the cab to check for bad pins or corrosion. Computer does not show ANY codes. I am stumped, the service manual has no trobleshooting tips for this problem. Thanks. Todd
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Once it has acted up, can you check the oil level? see if there are bubbles on the dipstick or if you can see in the tank, does there look like foam on the surface? Do you hear any noises from the pump like squealing?
It sounds like pump cavitation from air in the system, the only thing is it should self purge. Do you have any oil leaks? it could be drawing air in through these points if you do.
Hopefully someone else will have some more ideas.
It sounds like pump cavitation from air in the system, the only thing is it should self purge. Do you have any oil leaks? it could be drawing air in through these points if you do.
Hopefully someone else will have some more ideas.
Oil tank has sight gauge, no bubbles, level ok, no whining from either pump or problems with drive system. No leaks anywhere, just resealed the lift cylinders this morning. I did find that one of the pistons was not tightened on the shaft properly. I thought that I had found the problem, but no it did not help. Still pulses. If I idle it down while its pulsing I can hear the actuator buzzing back and forth, searching for center. Old actuator did the same thing. Im thinking the main box is having problems because it pulses on both controls (hand & foot). And its not showing any codes. Or could there be a problem in the spool valve block? I have the service manual for this model but it has nothing to say about hydraulics pulsing.
It almost sounds like the computer is telling the coils silly things, i know they are PWM controlled so they will make noises as they vary the duty cycle but not like a click click noise like it fully opens then closes then repeats causing jittery operation.
Sorry i can't be of more help, this style of machine is new to me, all mine have had mechanical linkages so i haven't had the joy of these problems... YET
Have you called your dealer? the service guys are pretty helpful. Its worth a phone call and see if its a known problem with a simple fix.
thetool
Well-known member
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- Mar 22, 2008
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Do you have bucket leveling? It's a valve directly across from the main control valve next to the hydraulic tank, under the cab. It's usually painted primer red. You activate it by a touch-pad switch on the left panel. If you have it, it will light up when you push the button.
Anyway, you have weird stuff going on with no codes, and unless it's your controller, your problems are mechanical(except for possibly the solenoid on the bucket positioning valve, which I don't think is monitored). If you have bucket postitioning, see if it acts the same with it on or off. Could be a sticky shuttle.
Check out your tilt cylinders. A slightly bent rod is easily overlooked and can chatter going in and out. Remove the pins from the rod eyes and swing your bob-tach by hand to see if it moves freely, and run your disconnected tilt cylinders in and out and see if they pulse. checking for ome king of mechanical bind.
You said you changed out your actuators. I don't know what you had before but if they were older you also needed to change the aluminum adapter. And if the actuators were yellow-stickered you needed to update the software on ALL controllers to V64 or higher. I don't know the current version but when I left last April, V64 was the latest and it was finicky-I often had to make sure I manually upgraded each controller, as the auto-update "All controllers" was glitchy.
Some of this stuff can be a real head-scratcher, but if you've checked everything and can't figure it out, a new controller us usually prescribed by elimination. I wish Bobcat would come out with a controller tester......
Good Luck
I think you should give a dealer a look at it as they can get an exact picture of what is happening through their diagnostic tool.Once hooked up they can visually see what the actuator is doing.
good luck
Thanks for the input guy's, no bucket leveling, adapters changed with actuators, tilt cyl's resealed w/no bent rods, I guess I will have to have the dealer look at it. I am 99% sure its electrical, I have been through everything but the valve block. Thanks again for the help, I am sure i will have more questions and hopefully some answers in the future.
