Mower deck belt flapping

[mvan85]

Hoping to get some feedback from others who have this mower deck, or have encountered a similar situation...the belt on my ZG227 mower, (deck model RCK54P-227Z) slaps quite a bit as it comes off of the pulley on the right side as it goes on the long run to the left side pulley (approx 3ft straight run of the belt from one pulley to the other). I initially suspected a bent spindle or pulley, but couldn't see a bend when I removed the spindle and pulley. Replaced the spindle anyways, but the result is still the same. When rotating the pulley with the belt removed, there is a slight "out of round" rotation, approximately 1-2mm where the rotation of the pulley versus a fixed point on the deck doesn't stay perfectly circular. Aside from causing premature wear to the belt, it's also causing the belt to rub various guide posts, as well as a nut that secures the mower gearbox to the deck.

First question I have is, how much belt slap/movement is expected and acceptable?

Second question is, what else could be causing the rotation to be slightly out of round, if the spindle and pulley are good, and the bearings appear smooth and operating normally?

Note: the out of round condition is also present on the left side pulley, but the belt doesn't travel as far to the center pulley as it leaves the left pulley, so the belt slap isn't as noticeable.

Thanks

 

[Captain13]

If the bearings are Ok and it sounds like you are confidant they are, the key way may be “egged” out a little due to wear. In that case, replacing the pulley should solve the problem. Before doing that, make sure the pulley is tight on the spindle. Since the pulley is wobbling, most likely, nothing is stuck in the pulley groove but it’s always worth checking to make sure there is no debris in the groove.

 

[mvan85]

If the bearings are Ok and it sounds like you are confidant they are, the key way may be “egged” out a little due to wear. In that case, replacing the pulley should solve the problem. Before doing that, make sure the pulley is tight on the spindle. Since the pulley is wobbling, most likely, nothing is stuck in the pulley groove but it’s always worth checking to make sure there is no debris in the groove.

Hi Captain,
The pulley slides over a hexagonal part of the shaft and fits snug with no sign of play or wear. With the pulley removed from the shaft, taking it out of the equation entirely, the shaft itself appears to oscillate or whatever you want to call it (rotates slightly out of round/not perfectly centered) when inserted through the bottom of the deck, up through the carrier and bearings. Now, this is less obvious compared to what the pulley itself does, because the circumference is so much smaller. By the time the issue reaches the outer edge of the pulley, it's more exaggerated, and even then it's only 1-2 mm off. I confirmed the issue is still present without the pulley by rotating the shaft, and measuring the distance to a fixed point on the deck as the shaft rotated. I'm starting to lean towards the bearings, potentially still rotating smoothly, but possibly being warped or bent due to an impact the mower took prior to my ownership. When I first bought the machine, one of the cups above the blade was cracked badly, so I assume it hit something fairly hard earlier in it's life. The machine has 550 hours, residential use, and those bearings are original to my knowledge

 

[mvan85]

Hi Captain,
The pulley slides over a hexagonal part of the shaft and fits snug with no sign of play or wear. With the pulley removed from the shaft, taking it out of the equation entirely, the shaft itself appears to oscillate or whatever you want to call it (rotates slightly out of round/not perfectly centered) when inserted through the bottom of the deck, up through the carrier and bearings. Now, this is less obvious compared to what the pulley itself does, because the circumference is so much smaller. By the time the issue reaches the outer edge of the pulley, it's more exaggerated, and even then it's only 1-2 mm off. I confirmed the issue is still present without the pulley by rotating the shaft, and measuring the distance to a fixed point on the deck as the shaft rotated. I'm starting to lean towards the bearings, potentially still rotating smoothly, but possibly being warped or bent due to an impact the mower took prior to my ownership. When I first bought the machine, one of the cups above the blade was cracked badly, so I assume it hit something fairly hard earlier in it's life. The machine has 550 hours, residential use, and those bearings are original to my knowledge

I'd also like to clarify, the issue is only horizontal, and does not appear to have any vertical movement present when looking at the side of the pulley.

 

[D2Cat]

Maybe a spindle is bent, but you installed a new one. It wobbles with only the spindle and bearings in play. Probably the bearings next!

 

[Captain13]

Maybe a spindle is bent, but you installed a new one. It wobbles with only the spindle and bearings in play. Probably the bearings next!

Agree.

 

[GreensvilleJay]

sigh, process of elimination...hopefully bearings..
if it's still there, some kind of 'spindle housing' damage (egg shaped ?? from previous hit ))