863 rolls down a hill when stalls

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Dave94044

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Dec 3, 2009
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I Have a 1998 863 Bobcat. If it stalls is just starts rolling down a hill with no way to stop it. Also the parking brake does not work. Other than that it seems to run fine. What are the possible causes that allow it to roll with the motor off? What are the possible problems that cause the parking brake not to work? Are these problems related? Thanks
 

mrfixitpaul

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Mar 28, 2009
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The design of the drive motor on the 863 & 873 will allow the freewheeling you are getting, so that is acting normally. Bobcat had corrected the problem of the rolls when stalls by having a rpm sensor on the engine feed to the brake controller so it would only be released if engine was running. The parking brake is located under the cab. you should see a gold colored solenoid coil that bolts to the chaincase cover. Remove the coil and see what is there for parts or what is missing. I don't have a pic of it but someone in the forum may? You should find a plunger for the solenoid, a few springs, a rectangular 'locking block' that will engage with the 2 discs you should see inside the case. I'm sure that something is either stuck/damaged/missing inside the brake mechanism.
 
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Dave94044

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The design of the drive motor on the 863 & 873 will allow the freewheeling you are getting, so that is acting normally. Bobcat had corrected the problem of the rolls when stalls by having a rpm sensor on the engine feed to the brake controller so it would only be released if engine was running. The parking brake is located under the cab. you should see a gold colored solenoid coil that bolts to the chaincase cover. Remove the coil and see what is there for parts or what is missing. I don't have a pic of it but someone in the forum may? You should find a plunger for the solenoid, a few springs, a rectangular 'locking block' that will engage with the 2 discs you should see inside the case. I'm sure that something is either stuck/damaged/missing inside the brake mechanism.
MrFixitPaul, Thanks for the response, what is the plan when it stalls on a hill? Is it suppose to engage the parking brake automatically? Is the operator suppose to engage the parking brake while rolling? Dave
 
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Dave94044

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MrFixitPaul, Thanks for the response, what is the plan when it stalls on a hill? Is it suppose to engage the parking brake automatically? Is the operator suppose to engage the parking brake while rolling? Dave
I read your reply more carefully. Are you suggesting my 98 883 was prior to the RPM sensor system? When did they start putting on the sensor? Dave
 

mrfixitpaul

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I read your reply more carefully. Are you suggesting my 98 883 was prior to the RPM sensor system? When did they start putting on the sensor? Dave
Not sure when the brake operation was updated, there might have been a 'recall' or field modification to update the older ones as well, I can't remember, but if you look on the bellhousing the rpm sensor has 2 wires and will be threaded into about 1in. hole to sense flywheel rpm. Does your parking brake work at all?
 
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Dave94044

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Not sure when the brake operation was updated, there might have been a 'recall' or field modification to update the older ones as well, I can't remember, but if you look on the bellhousing the rpm sensor has 2 wires and will be threaded into about 1in. hole to sense flywheel rpm. Does your parking brake work at all?
The parking does NOT work at all. I don't even hear a noise of a relay when trying to use the parking brake. When you lift the saefty bar is it also suppose to engage the parking brake? Dave
 

OldMachinist

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The parking does NOT work at all. I don't even hear a noise of a relay when trying to use the parking brake. When you lift the saefty bar is it also suppose to engage the parking brake? Dave
TractionLock001.jpg picture by calfranch

RPM_Sensor001.jpg picture by calfranch

Yes, the traction lock/parking brake should engage when you lift the seat bar.
 
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Dave94044

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Yes, the traction lock/parking brake should engage when you lift the seat bar.
"Yes, the traction lock/parking brake should engage when you lift the seat bar" Is the traction lock and parking brake the same thing? Is the traction lock/ parking brake supose to automatically engage when the motor stalls to prevent rollaway? if not can the traction lock/parking brake be engaged while the 863 is rolling down a hill? Thanks Dave
 

OldMachinist

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"Yes, the traction lock/parking brake should engage when you lift the seat bar" Is the traction lock and parking brake the same thing? Is the traction lock/ parking brake supose to automatically engage when the motor stalls to prevent rollaway? if not can the traction lock/parking brake be engaged while the 863 is rolling down a hill? Thanks Dave
The traction lock and parking brake both engage the same mechanism in the scan I posted above. The parking brake pedal just has a switch on it to engage the traction lock solenoid. Did you check to see if the parts are all there? Also did you check if it has the RPM sensor?
 
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Dave94044

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The traction lock and parking brake both engage the same mechanism in the scan I posted above. The parking brake pedal just has a switch on it to engage the traction lock solenoid. Did you check to see if the parts are all there? Also did you check if it has the RPM sensor?
I removed the parking brake/traction lock solenoid to discover the most of the parking brake parts were missing. The two lobed disc are there. But nothing inside the solenoid or anything to engage in the parking brake disk. I assume the previous owner(s) took this out because they couldn't get the parking brake/traction lock to disengage. I got a parts blowup and I am trying to tell what is missing. I should have them ordered this week. After I install them I assume I will be looking for the problem that made the previous owner remove the assembly in the first place. What exactly controls this solenoid? The RPM sensor, the foot parking brake switch, the operator bar? Did I miss anything? Is there a computer involved? Thanks for your help Dave
 

OldMachinist

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I removed the parking brake/traction lock solenoid to discover the most of the parking brake parts were missing. The two lobed disc are there. But nothing inside the solenoid or anything to engage in the parking brake disk. I assume the previous owner(s) took this out because they couldn't get the parking brake/traction lock to disengage. I got a parts blowup and I am trying to tell what is missing. I should have them ordered this week. After I install them I assume I will be looking for the problem that made the previous owner remove the assembly in the first place. What exactly controls this solenoid? The RPM sensor, the foot parking brake switch, the operator bar? Did I miss anything? Is there a computer involved? Thanks for your help Dave
The solenoid is controlled by the BICS(Bobcat Interlock Control System) and receives inputs from the RPM sensor, seat bar and parking brake switch. If the traction light isn't flashing on the control box then the wiring and solenoid are likely allright.
 
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The solenoid is controlled by the BICS(Bobcat Interlock Control System) and receives inputs from the RPM sensor, seat bar and parking brake switch. If the traction light isn't flashing on the control box then the wiring and solenoid are likely allright.
Thanks for this info... have had this problem in the past.
 
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