Schifference
Well-known member
- Joined
- Sep 23, 2020
- Messages
- 86
How to Diagnose a Drive Problem on a Bobcat 642 and possibly Fix it yourself in real DIY Fashion saving you thousands of dollars. I had a Problem with the Hydraulic Hydrostatic Drive Motor on Right Side. It was Barely Responsive and Very Noisy. To Diagnose the Problem, I Switched Both Hoses on both sides of the pump, The bigger hoses toward the rear, that go to the Drive Motors. I kept the same hoses on the same side of the pump but switched them from front to back. This made the Controllers work totally opposite of normal. The Problem no longer existed on the Right side and went to the Left. The Conclusion was that the Motor was Good and there was a Problem with the Pump. If you are lucky the possible solution might just be a dirty screen in the Center of the Three fittings on the Block. Or it might just be that the Wear/Wafer Plates are scratched and need Sanding. Sanding is accomplished by removing the Wear/Wafer Plates and wet sanding with beginning with 400 grit and working to 1500 using WD40 as lubricant to remove scratches in brass side of plate. Make sure to keep the plates separate because they are side specific. In my case, the Rotating Group needs replaced. They can be acquired new for a fraction of the cost of a rebuilt complete pump. Here is a youtube link to the process. https://youtu.be/OS4FhW8S0bA
