Owatonna Mustang 1000 drive pulley

[Quad Raider]

Just finished rebuilding the VH4D on a friend's vintage Mustang 1000 skid steer loader. Solved many problems along the way, but a new one has cropped up. The drive pulley does not want to stay on the output shaft. This engine has the short, non-tapered shaft on the PTO side. The two-piece pulley slides on to the shaft and has two holes for set screws, plus a large keyway. Yesterday, while letting the engine run at idle as per the manual's recommended break-in, the pulley slid off the shaft after about 20 minutes. It didn't come all the way off, just far enough to indicate that it was loose. I have tried using two small set screws in each hole (the way it was when I disassembled it). The key has definitely seen better days, but would a new key make that much difference?

 

[Quad Raider]

I think I may have solved the problem by using a longer key. Along the way I discovered that the moveable sheave on the driveshaft was worn out, which was causing the belt to jump and putting more stress on the sheave on the engine. So far the fixes are working fine. Knock on wood.

 

[Tazza]

I think I may have solved the problem by using a longer key. Along the way I discovered that the moveable sheave on the driveshaft was worn out, which was causing the belt to jump and putting more stress on the sheave on the engine. So far the fixes are working fine. Knock on wood.

Glad its working. Is there any way you can get the key way cut a little wider? that way the larger key won't bind up and will allow it to slide easily? I guess its an option if your current fix doesn't hold up.

 

[Quad Raider]

Glad its working. Is there any way you can get the key way cut a little wider? that way the larger key won't bind up and will allow it to slide easily? I guess its an option if your current fix doesn't hold up.

The key I'm using isn't any wider than the old one, it's about 3/4 of an inch longer. The key way is a little worn, which is probably the reason for the problem in the first place. I didn't notice the wear until after I had already reassembled the engine. Doh! On this model, the engine-side of the sheave doesn't move back and forth on the shaft, anyway. It's the outside of the sheave that moves back and forth. I hope to actually do some work with the loader this weekend so we'll see how it holds up.