Bobcat 751 issue

[WeekendWarrior]

I am having some problems with what I believe is the "operate loader" function kicking out all by itself. In the middle of operating the loader I all of a sudden cannot operate hydraulics or move the loader at all. When I look at the panel I notice thatr I have to press the operate loader button and then all is good untill it happens again. This is very frustrating and perhaps hard on the unit especially if you are cruising down the road because you all of a sudden go from say 10mph to having the brakes kick on instantly. Today I noticed that when this happens the seat bar light tended to flicker so I am assuming that this is happening due to a bad connection where the unit senses that the seat bar has been raised and then kicks you out of operations untill you press the operate loader button......any ideas?

 

[Tazza]

If you check the BICS box, see what the lights read. It sounds like a bad seat sensor, it will lock the hydraulics out and engage the brake. All the lights should be on when the sensors detect you ar on the seat and the seat bar is down.

 

[WeekendWarrior]

If you check the BICS box, see what the lights read. It sounds like a bad seat sensor, it will lock the hydraulics out and engage the brake. All the lights should be on when the sensors detect you ar on the seat and the seat bar is down.

Thanks Tazza, When it happens all lights arte out except for the seat bar however I think that the seat bar light briefly goes out causing everything to go out and propting the operator to push the operate loader button again to engage the rest of the lights and operate the loader normally again. Today when it happened I noticed the seat bar light going on and off all by itself before I had a chance to push the operate loader button. Where are these sensor and connections located? How do I check to see if contact problems are to blame. Thanks, Peter

 

[Tazza]

Thanks Tazza, When it happens all lights arte out except for the seat bar however I think that the seat bar light briefly goes out causing everything to go out and propting the operator to push the operate loader button again to engage the rest of the lights and operate the loader normally again. Today when it happened I noticed the seat bar light going on and off all by itself before I had a chance to push the operate loader button. Where are these sensor and connections located? How do I check to see if contact problems are to blame. Thanks, Peter

The seat bar sensor is where the seat bar pivots, i think the left hand side. Its non contact, it uses a sensor and magnet.
You mention ALL lights go out, does that include the power light? it could be a bad ground or wore in the harness somewhere. If you loose power the brake will engage and the hydraulics will lock you out.
You shouldn't have to press the push to operate button every time. You should sit down, lower the seat bar, start and the brake should dis engage with the pedal on the floor. Mine never needed to hit the PTO button for it to un-lock all functions. SOunds like a sensor issue, even the seat one could be to blame. The seats do rott out causing the sensor to not function correctly.

 

[mrfixitpaul]

The seat bar sensor is where the seat bar pivots, i think the left hand side. Its non contact, it uses a sensor and magnet.
You mention ALL lights go out, does that include the power light? it could be a bad ground or wore in the harness somewhere. If you loose power the brake will engage and the hydraulics will lock you out.
You shouldn't have to press the push to operate button every time. You should sit down, lower the seat bar, start and the brake should dis engage with the pedal on the floor. Mine never needed to hit the PTO button for it to un-lock all functions. SOunds like a sensor issue, even the seat one could be to blame. The seats do rott out causing the sensor to not function correctly.

If it has the PTO button then once it is activated the seat sensor is 'out of the loop', if it even has the seat sensor still(it doesn't need to be there). It sounds like the seatbar sensor is the problem. Check the pivot bolts for tightness, just a little movement at the sensor is enough to cause it to think you lifted the bar.

 

[WeekendWarrior]

If it has the PTO button then once it is activated the seat sensor is 'out of the loop', if it even has the seat sensor still(it doesn't need to be there). It sounds like the seatbar sensor is the problem. Check the pivot bolts for tightness, just a little movement at the sensor is enough to cause it to think you lifted the bar.

Thanks Mr Fixit, That's right I have the PTO button and have to use it everytime I raise the bar in order to operate the machine. Taking the seat sensor out of the question leaves less for me to trouble shoot. I will cheack the bar sensor on the left and check the pivit bolts. I cannot make the lights go on and off by jiggling the bar. I suspect the problem is either in the sensor itself or in a connection/cable on the way to the box. Will post what I find. Thanks

 

[WeekendWarrior]

Thanks Mr Fixit, That's right I have the PTO button and have to use it everytime I raise the bar in order to operate the machine. Taking the seat sensor out of the question leaves less for me to trouble shoot. I will cheack the bar sensor on the left and check the pivit bolts. I cannot make the lights go on and off by jiggling the bar. I suspect the problem is either in the sensor itself or in a connection/cable on the way to the box. Will post what I find. Thanks

Well I think with your help I have found the problem. As you guys mentioned the seat bar sensor appears to have been the problem. Today I checked the plug at the seat side of the seatbar (you have to tilt it up to see it) and found one of the three socket connectors to be misalligned. I simply used a very small set of needle nosed pliers and reconnected the plug. I used it for about three hours today without a single incidence of getting locked out. Thanks everyone for their help. Peter