Hydraulic brake question

[zell66]

Until last year never had a boat with Hydraulic brakes. After sitting for winter took boat out last weekend. While I was driving to landing to bring boat out of water the driver side rear axle locked up. I stopped put into reverse for 6" or so and then forward and worked fine. Boat dealer says could be just rust but how does one check this type of system?

 

[Watermann]

You may need to replace the wheel cylinders and or the actuator in the coupler. Only way to know is to tear it down and see how things look.