Sheave/ pulley adjustment

[No1umfan]

I’ve got a 9 foot flail mower. Need to replace the belts. I found that the pulleys really are not in perfect alignment. So I’m trying to remove this top one to move it out about 3/16. But it won’t budge. I’m afraid of putting more force on the gear puller. Could it possibly bend the sheave out of alignment. Also I noticed there are extra holes after I removed all the bolts. I’ve seen this where you insert screws in there and screw those in to push the pulley off. Strange thing is is that the holes are smaller than the bolts. Usually they’re the same size. Any advice??

 

[nyone]

Yes on those you screw the bolt into the sheve to remove not the pully. That looks to be an old Alamo flail?
3/16 really isnt that much.

 

[No1umfan]

It’s a Ford 918 H. I put new belts on with that 3/16 misalignment. And I got a temperature reading up about 200° on the sheave after running the mower for about 15 minutes. The belts were 48 inch long whereas the OEM is 48.8. not sure if that would make a huge difference but that’s what happened.

 

[timbatrader]

using a puller will just tighten it on the shaft. The sheave is tapered you need to move the pully off the taper by using a hammer and drift to knock the pully back towards the mower and release the taper then remove the sheave. When you reassemble it consider putting back with the taper facing the other direction as long as you have room to access the retaining bolts it will make it easier to remove next time

 

[John0829]

Those smaller tapped holes are to push the sheave off of the taper lock hub. Use good bolts that will not mushroom as it could be really tight.

 

[ArlyA]

It’s a Ford 918 H. I put new belts on with that 3/16 misalignment. And I got a temperature reading up about 200° on the sheave after running the mower for about 15 minutes. The belts were 48 inch long whereas the OEM is 48.8. not sure if that would make a huge difference but that’s what happened.

If the sheves are 24" from each other, 3/16 out of plane is not worth messing with. Could they have been loose, slipping some and create that 200 degree heat? Could you have a bearing going out?

 

[No1umfan]

Those smaller tapped holes are to push the sheave off of the taper lock hub. Use good bolts that will not mushroom as it could be really tight.

Ugh. can’t find bolts to fit in those screw holes. They are really an odd size. 10-24 is too small and 1/4 - 20 is too big. In metric 5 mm is too small and six is too big.

 

[arto98607]

....................snip..................... When you reassemble it consider putting back with the taper facing the other direction as long as you have room to access the retaining bolts it will make it easier to remove next time

I disagree with this advice sir!

 

[arto98607]

I’ve got a 9 foot flail mower. Need to replace the belts. I found that the pulleys really are not in perfect alignment. So I’m trying to remove this top one to move it out about 3/16. But it won’t budge. I’m afraid of putting more force on the gear puller. Could it possibly bend the sheave out of alignment. Also I noticed there are extra holes after I removed all the bolts. I’ve seen this where you insert screws in there and screw those in to push the pulley off. Strange thing is is that the holes are smaller than the bolts. Usually they’re the same size. Any advice??

It's a cast iron pulley so it does not bend, instead it breaks if you apply too much force with a puller or hit in a wrong spot with a hammer!
Using a puller on the outer edge will be counterproductive and possibly just make the taper bushing grab on tighter to the shaft.

It looks like whomever installed it last time tightened the tapered bushing bolts all the way down so it may be in pretty tight.

Why not check if the smaller pulley comes loose easier and if there is enough room to move the smaller pulley 3/16" in the opposite direction?

By the way, in your second photo it looks like the smaller pulley has the extraction bolts you are looking for.
Or just keep looking until you find out what size bolts you will need?


Here is what the rest of a typical (much smaller) H-style tapered bushing looks like.

 

[K5lwq]

Ugh. can’t find bolts to fit in those screw holes. They are really an odd size. 10-24 is too small and 1/4 - 20 is too big. In metric 5 mm is too small and six is too big.

What about getting a 1/4-20 tap and resize the holes?