I have a 2012 Skyjack SJ111-3219 that is in great shape. After some use, it decides to act up and wont allow the lift to rise or drive. I end up lowering the lift and looking for the problem. I plug in the battery charger and 5-10 minutes later, its working again for a brief period but not always (no consistency). I've been cleaning connections, removing some minimal corrosion. And is still doing the same thing. Sometimes I can just rock the lift a little from inside the platform and it works. Then I tried tapping on the pump motor and I am back in business for a short time. Then, lower the lift, tap the pump motor again, and I am in business briefly. The tapping seems to be working but wondering if it could it be motor brushes or is the motor overheating?? Please help.