751 BobCat Hydraulic Problem

[rbryant]

I have a 751 Bobcat that the red hydraulic light won't go off. In the beginning the light would stay on for a few seconds after I started the machine and then it would go off and everything worked fine the rest of the day. I don't use this machine real often, it has 1400 hrs on it. Eventually it took longer and longer for the light to go off and I would have to rev the engine for 2 or 3 minutes to make it go off and the hydraulics start working. Nothing works as long as this light is on. Now I can't get the light to go off at all. I changed the filter but it didn't help. Does anyone know what might be going on..Thanks guys!!

 

[jerry]

sounds like it may be the pressure sensor, try disconnecting the sender and see what happens. If everything works then replacing the sender might do it.

 

[OldMachinist]

What's temperature where the machine is stored? The colder the oil is the longer it take for the light to go out. Also the wire may have just been working loose on the sender and now it not making a connection at all.

 

[rbryant]

I disconnected the sender, the one at the filter with 3 wires, and the light goes out but still nothing happens. I suspect this sender feeds a solenoid on the system somewhere. Thanks!!

 

[Tazza]

I disconnected the sender, the one at the filter with 3 wires, and the light goes out but still nothing happens. I suspect this sender feeds a solenoid on the system somewhere. Thanks!!

The light is for charge pressure, if it detects its low the light will go on.
With the sender removed, install a 200 PSI gauge into the hole and measure the charge pressure, it should be about 120 PSI from memory.
You mention the hydraulics will not work, is this drive or lift/tilt? My 751 didn't have anything to lock me out if it detected the charge pressure was low.....

 

[mrfixitpaul]

The light is for charge pressure, if it detects its low the light will go on.
With the sender removed, install a 200 PSI gauge into the hole and measure the charge pressure, it should be about 120 PSI from memory.
You mention the hydraulics will not work, is this drive or lift/tilt? My 751 didn't have anything to lock me out if it detected the charge pressure was low.....

Sounds like 2 separate issues here. 1 is the hyd light, the 2nd sounds like a BICS issue. Are all the lights on the panel beside the seat lighting up when the machine is running, person in the seat, seatbar down and brake pedal off (also press the 'push to operate' button if it has one)?

 

[rbryant]

Sounds like 2 separate issues here. 1 is the hyd light, the 2nd sounds like a BICS issue. Are all the lights on the panel beside the seat lighting up when the machine is running, person in the seat, seatbar down and brake pedal off (also press the 'push to operate' button if it has one)?

Problem solved. The jam nut had worked loose on the drive belt tensioner and let the tensioner back off enough to slip. I tightened the tensioner and the jam nut and all is well. Thanks for all the responses.