Bobcat 720 next issue - tranmission

bdoyle · May 5, 2020

Yeah I bought a basket case and I figured just about every could go wrong. So before I buy the Repower Specialist kit, I need to determine what was the engine rotation and does the drive system work. I guess the engine could be a clockwise or counter-clockwise rotation. I was thinking taking the tires off and rotating the input shaft with a impact driver. Maybe loosen a fitting or two to see if oil is moving in the proper direction. Whats got me worried is the fact that the 720 rolls if you push it. Could be the high pressure relief valves have been removed or maybe it is just low on hydraulic fluid. Just trying to assess the problems before I throw a bunch of money at it. Not normally a lucky guy but I can head off trouble by paying attention.

laurencen · May 5, 2020

you can use the starter on the motor to load it on a trailer, slow but works, when we had the motor out and needed it moved we used a battery impact on the coupler shaft, we could not move it just pushing, wheels were locked, not sure if low fluid woud make it move easier

flyerdan · May 5, 2020

My 700 will roll too, it was the first generation of hydrostatic drive so they probably made some changes along the line. The only time it was an issue for me was when I anchored a come a long to it and had to dig in the bucket to keep it from creeping.
If you have a starter handy, just bench test it and see which way it spins. Chances are it goes CCW, so the engine would run CW when you are standing behind the machine.

bdoyle · May 13, 2020

Still having issues with what is the proper pump shaft direction. Spec sheets show Wisconsin engine as CCW. But that all depends on what side you are on. Found a picture in the service manual and it shows pump rotation as CCW IF you are standing behind the unit. Front (bucket side) it would be CW. So, with direct engine coupling, wouldn't I want a CCW rotation engine (looking from back)?

laurencen · Jun 9, 2020

thats how I see it looking at your diagram

bdoyle · Jun 11, 2020

I was able to verify the direction by using the engine block, cam and crankshaft. Put both in case and rotated the crank CCW. With the angle cut gears this pulled the cam into the block against the bearing surface. CW rot pushed the cam out against the cam cover. So now I can move forward and see it I can get the wheels to turn by rotating the pump with a drill motor while jacked up with wheels off.

laurencen · Jun 11, 2020

FWIW when we had the motor out the 843 for rebuild we moved the machine around with a drill on the pump shaft, even loaded it on the trailer that way

bdoyle · Jun 30, 2020

Well, tried the drill and got nuttin. While drilling a few post holes I noticed the pto output rotated the proper direction to drive the pump on the 720. Welded a stub on my adapter and spun it up. Nuttin. Figure the pump lost its prime. Should be able to get to that today or tomorrow. The low pressure hoses on the suction side and oil cooler look pretty punky so I'm sure thats not helping.