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bobcat 751 aux troubles

wheeliewebb

Member
Joined
Oct 18, 2009
Messages
17
Location
INDIANA
sorry for the long post, just trying to give a good view. When I hit my aux switch in my handle(ahc) my ram will trvel out even if i just bump my momentarys. No, I don't have it in continuous operation. Once my ram travels out all the way to the end it acts like it builds pressure for about 2 seconds. then once that pressure relieves i can bring the ram back in. But if I don't wait those few seconds for the pressure to relieve, my ram will return at a snails pace. I think I'm fighting pressure with pressure. I have replaced fluids, filters, elec. packs on top of control valve(both of them), the 2 spools under them, removed the long aux spool (top rt of control valve) good shape? I'm at a loss
bobcat dealer says its my attachment but my attachment works on another 751 fine with (ahc) any help would be great.:beatsme
 

mrfixitpaul

Well-Known Member
Joined
Mar 26, 2009
Messages
109
Location
maine
Have you checked the springs at both ends of the auxiliary spool in the control valve? There should be 2 on either end, behind the 2-bolt cap. Also a broken washer there ??
 

wheeliewebb

Member
Joined
Oct 18, 2009
Messages
17
Location
INDIANA
ya i checked them on the rt side of control valve but not on the left side. If the springs are not broke, you got any other idea thanks brandon
 

mrfixitpaul

Well-Known Member
Joined
Mar 26, 2009
Messages
109
Location
maine
Maybe the problem is in the thumb switch? If you swap the wires for the 2 solenoids does the problem move to the other direction? That would rule out a valve problem and make it a control problem.
 

wheeliewebb

Member
Joined
Oct 18, 2009
Messages
17
Location
INDIANA
I bypassed all the controls by taking 12 volts straight to the solenoids on top of control valve? I also had tried changing the solenoids around. Can you use your momenatries on either joystick(ahc) left or right, center push button left to right? Thanks Brandon
 

mrfixitpaul

Well-Known Member
Joined
Mar 26, 2009
Messages
109
Location
maine
I think the solenoids are not designed for straight 12 volts. They use a computer controlled PWM system to allow for feathering capabilities. Not sure if the handles interchange left to right. When you gave it 12 volts, did the auxiliaries function? Did they hang up as before?
 

bobcatmechanic

Senior Member
Joined
Mar 26, 2008
Messages
429
Location
kansas
Occupation
bobcat mechanic
yeah they are not designed for twelve volts i dont remember the exact number but 8 volts i believe is the number yeah i would check the handle can you hear the aux on and dead headed when they are not on. it could also be the bics controller is it a g or f series g triangle head lights f squar it could also be the aux controller depending on the series
 

wheeliewebb

Member
Joined
Oct 18, 2009
Messages
17
Location
INDIANA
its an f series and when i put 12 volts straight to them the did not work correctly either. I already replaced the bics solenoid and spool. hay, bobcatmechanic when you said aux controller are you talking about the control valve actuators on the front left side of the control valve as your looking at it in the machine. thanks brandon
 

wheeliewebb

Member
Joined
Oct 18, 2009
Messages
17
Location
INDIANA
hay guys thanks for the help. come to find out the 2 spools i replaced on top of the control valve were bad from the factory. got 2 new ones from bobcat friday and put them in today and it works great. thanks again brandon:)
 
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