Recycler II 20438: shearing off nubs on main drive pulley

[aggiejet]

I replaced the blade brake on the Recycler II. I am having trouble getting the brake/flywheel assembly put back on the mower with shearing off the nubs that are on the pulley that attaches to the spindle and between the mower deck and the flywheel. If I tighten the nut real tight, I can't pull the starter rope. If I get it too loose, the flywheel shears the nubs off of the pulley. I have done that twice now, and am on my third pulley. The guy at the parts place asked a mech in the back, he said there is no trick. He said sometimes the holes in the flywheel get worn out and there is too much play, thus causing the shear. I am not sure that is right, because it seems it would have sheared off by now on its own instead of now on reassembly.

What am I doing wrong?

 

[Rivets]

You must make sure you are aligning the pulley "nubs" with the slots on the flywheel and the flywheel is resting flat on the pulley as you are tightening the Locknut. The trick I use is to first tighten the nut by hand and then check for a small amount of play between the flywheel and pulley. Next make that the belt is free after tightening the nut with your wrench a small amount. If the belt gets pinched during assembly, you will cock the flywheel and not be able to tighten it properly, causing the condition you have when you try to pull the starter rope. Continue tightening and checking until you are sure it is good and tight. Go slow, you can not rush this assembly and when you are done you should be able to turn the BBC flywheel by hand without moving the belt.

 

[aggiejet]

I can get the flywheel and brake drum assembly put together and tightened on the spindle/shaft, with the nubs of the pulley engaging the flywheel with no wobble in the flywheel. It is the subsequent steps when I get in trouble and break off the nubs. (happened again yesterday on my third attempt at reassembly)

If you tighten the lock nut on the spindle/shaft too much, the brake cannot hold the brake hub and the hub will spin with the flywheel when you pull the starter rope. So I loosen the spindle nut just enough so that the brake will hold the brake hub in place while I pull the starter rope, allowing the crank/spindle to turn, while the brake hub (which the blade attaches to) is held in place.

Next, I put the belt on. This is where I get in trouble. After I put the belt in place, (the belt lies between the brake hub and the flywheel) the brake will not hold the hub in place while I slowly pull the starter rope because the belt causes too much friction between the brake hub and flywheel. In other words, I pull the starter rope, the flywheel turns and the brake hub turns. So I keep loosening the spindle nut in very small increments, trying to find just the right about of torque to allow the flywheel to turn but not the brake hub. Next thing I know, I have sheared off the nubs again.

<<Go slow, you can not rush this assembly and when you are done you should be able to turn the BBC flywheel by hand without moving the belt.>>

This is the point I can't seem to get right. I can't find the right amount of torque on the nut to be able to turn the BBC flywheel without moving the belt.

Any suggestions?

Thanks,
Mark

 

[Rivets]

The brake you are talking about is not designed to keep the flywheel or pulley hub from turning. It's job is to stop the blade when the BBC handle is released. As I said earlier tighten the pulley, flywheel and brake drum while making sure that you don't pinch the belt. Here is a parts breakdown if you don't have one, to make sure that everything is in the correct order.

https://lookup3.toro.com/classes/doGetPub/?pubid=4157

 

[aggiejet]

The brake you are talking about is not designed to keep the flywheel or pulley hub from turning. It's job is to stop the blade when the BBC handle is released. As I said earlier tighten the pulley, flywheel and brake drum while making sure that you don't pinch the belt. Here is a parts breakdown if you don't have one, to make sure that everything is in the correct order.

https://lookup3.toro.com/classes/doGetPub/?pubid=4157

I understand that the brake stops the hub, which is connected to the blade. This allows you start the engine without spinning the blade.

The difference between what you suggest and what I have done only differs on when to put the belt back on. I reassemble the pulley, flywheel, and brake drum while I have the brake pulled back out of the way. Then I release the brake into position and then put the belt in place. I do it this way because I run out of hands otherwise.

I am not exactly sure what you mean by don't pinch the belt, as there has to be some "pinching" between the flywheel and brake hub in order to create enough friction between the hub and flywheel to turn the hub/blade. When you pull the lever back up at the mower handle, it pulls the slack out of the belt via the pulley/brake plate mechanism and the blade spins because of the friction between the brake hub and flywheel?

I have a exploding parts diagram already, but thanks anyway.

thanks for the help,
Mark

 

[Rivets]

What I mean by "don't pinch the belt" is make sure that all the while you are tightening the locknut the belt must be free. When you are finished tightening the nut the pulley, and brakedrum should be able to turn (with resistance as the brake is still on) and the belt should not move. I've done this multiple times and the locknut must be extremely tight, or you will shear the nubs. Might be time to take it in to solve your problem.