bobcat 873 turbo hydraulics

fried of mine has an 873 bobcat. has an intermittent problem where it will lose all bucket controls randomly. drives still work. after the machine cools off for a few hours, it will start working again.. has been to the bobcat dealer several times, they are at a loss. now they think it may be a computer module. but not sure. the bucket controls are fly by wire. any thoughts??? the module is big money, and no guarantee it will fix the problem. thx

Once Bobcat started using the BICS system in their machines, they began putting a solenoid valve on the valve block that shuts off everything but the drives when any of the safety switches are tripped. They ran into problems several years down the road with the seat switches, and have since developed a new computer module that allows the seat switch to be bypassed. I can't say where the cutoff is on any of the many different models, but if the BICS computer that sits behind, and to the right of the seat has a picture of a seat on it, then more than likely that is his problem. I just put the update on a 751 and it cost nearly $400.

With that said, it's possible the coil in the solenoid valve is going bad, and breaking down when it gets hot. When it cools down it beings working again, until it gets hot....and so on.....



When you raise the cab you'll usually see a connector with a tie wrap around it saying not to mess with it. The coil, so Bobcat says, is not 12 volt, so using straight 12v power to it for too long will burn it up. However, you can put 12 volts on it for a few minutes without any problem. So, one way to check the solenoid is the next time the problem occurs immediately try hooking a 12 power source to the solenoid, and see it things unlock. If they do the coil more than likely isn't the problem, and it lies in the computer module instead.

Another customer had a machine also doing similar to what you describe. In his case it was the pins in the connector that hooked up to the BICS module. What I did that fixed it was to take each wire out of the connector individually, and bend the little spring arms back to the inside on each one. That way when the male half of the connector was plugged back into it, they made better contact, and the problem was solved.

In either situation, look behind you at the lights on the BICS module the next time the problem happens. If all the lights are lit, and the machine still won't move, then it's more than likely the valve. If one, or more, of the lights is out, then the problem is with the sensor associated with that light.

In general a problem like you describe is always going to be a problem with the BICS on the older machines. Now if the machine is one of the newer ones, sorry, but I haven't messed with any of them enough to offer up any advice yet.

thanks wayne, we will check those out!!