Bobcat 753C

[bharle]

753 C series, serial #512729862, Mfg: 1996

"arbitrarily" when operating, it instantly locks up all the wheels (both sides). But the hydraulics still work (bucket operates). Hitting the release button does not change anything. The only way to get it to move again is to shut off the machine and restart, hitting the release button again of course. Then it may operator for 10 minutes, or 2 hours before it happens again.

I found another thread in here that mentions to check the ground wire behind the operator left shoulder. It was clean, but I unbolted and shined everything up and bolted it back down with no change.

I should have done so before posting this, but I have not looked at the BICS lights after it locked up.

From what I've found:
- BICS could be bad
- BICS plug could be corroded, not making great contact. A) Can you tell me how that unplugs, just wiggle and pull is there something else to it? It didn't easily pop out so I was afraid I would break the plug...

- mice have eaten a wire some place and it is shorting out.

Any other suggestions?

It is a brutal stop when you least expect it and the wheels all lock up! The fact that the loader hydraulics keep working seems like it should point to something but I am not experienced with this machine.

thank you in advance for any advice you may have
bruce

 

[reaperman]

Does your machine have the seat switch still installed? That was a trouble spot for the C series machines until bobcat stopped using them.

 

[reaperman]

You could always remove the parking brake until you figure it out, that's what's causing it to abruptly stop. Its solenoid activated and found under the cab right between your legs as you're sitting in the machine.

 

[spitzair]

Clean up anything and everything under and behind the seat. I had the exact same symptoms on our 873C when we first got it, I always carried chains and such around in the cab with me in my 732 and carried that habit forward to the 873. It would randomly stop just BAM like that but the arms and bucket would still work. Figured out that anything behind or under the seat can stop the sensor from sensing and the computer decides you're stopping right then and there. Cleaned all the junk out from under and behind the seat and no more problem. Actually it's a handy anti-theft device too - one day my dad had the machine parked with a few others in North Vancouver overnight and a bunch of criminals came with a couple of 53' van trailer and loaded up all the machines except ours as my dad had placed some wedges under the seat inconspicuously to deter theft and it worked. They tried to steal it, got it running and got the arms up but couldn't get the machine to move so they abandoned their efforts. In the morning it was the only machine left!