Hello guys. Need to scratch some heads in here. Got a 2017 t590 that lost parking brakes. Unsure of the conditions on how. Unit was brought back with complaint it rolled. Sure enough it’s got nothing. Crank it up drop the bar and go. I’m assuming that they are spring applied hydraulic release ? Of course that’s my assumption they work similar to the rest. I can see one side possibly failing but both sides at once? Here agin I’m working under the assumption they are spring applied. Does anyone have any experience working on this particular system and might be able to tell me if that is in fact the case. Thanks guys
Yes, Bobcat track machines have spring applied parking brakes in the two drive motors, hydraulic pressure release to overcome the springs in the brakes. If it will drive without you releasing the parking brake you could have a faulty brake control solenoid valve. The valve releases the brakes using charge pressure going to the drive pumps. You need to disconnect the input supply line at the brake valve and plug it, see if the machine will still drive.
Thanks willie. I did that and still got no brakes. Borrowed another valve assy from a second machine for testing. Leaning towards a internal issue with the springs. But still seems odd both at once but that’s really all it could be at this point. Thoughts ??
I could see a hydraulic issue with them not releasing but since they won’t engage and if they are spring applied my mind keeps thinking it’s something inside with the actual spring side of things
Well problem found...
Comprehensively Donald Ducked.............. I wonder how the ***k that happened.? Not the rollover surely.? I wonder if it was skull-dragged with the engine dead after it was rolled and that tore up the brakes.?
Nige . It wasn’t a roll over like upside down it was rolling of when parked on un even ground. I’m thinking maybe the charge pressure to the brake release might have been inadequate and the brakes released enough to move but drug???
That would be odd in itself as it should have sounded an alarm for low charge pressure. And on a Bobcat, if you ignore a low charge pressure warning the main controller will soon after that put it in shut down mode. I have no good explanation how those brakes got trashed like that.