54" BAD BOY MZ Magnum (zero turn) Blade Replacement OEM Blades - Blades Slipping

[Dionne Thacker]

First blade replacement. Went very smooth. Maybe too smooth.
Completed the installation, took the mower out for a test-drive, it was working great. About 5min the blades stopped turning.
Disengaged the blades with the cutoff switch, took it back into the garage, lifted it and checked the torque on blade bolts to ensure 110 ft lbs.
Torque was good.

• Started mower
• Engaged the blades (low speed)
• Belt squeal and smell
• Tightened front tension spring
• Started & engaged the blades (low speed) no squeal
• Test drove - engaged blades at full speed, squealing.
• Gave up on it before I took a hammer to it.

What could cause the belt to loosen when I never touched it while replacing the blades and the last time I ran the mower (before the blade change) it was fine?

What step did I miss when changing the blades that might cause the belt to loosen?

BTW - I never even touched the belt at all. All the work was performed under the deck the entire time.

 

[lugbolt]

maybe a part damaged when lifting the mower for service? Like bent deck shell , etc. Look it over closely....

 

[MParr]

Why do you engage the blades at “low speed”?
It sounds as if the belt is glazed. Check all of your pulleys, idlers, and spindles. The belt may be on the wrong side of a keeper.

 

[Bertrrr]

New blades maybe bigger strain on the belt , might need a new belt, if it's squealing and it's tight, Get a new one

 

[hlw49]

I think you should buy a new mower then that would solve all your problems. LOL Just Kidding

 

[Dionne Thacker]

Why do you engage the blades at “low speed”?
It sounds as if the belt is glazed. Check all of your pulleys, idlers, and spindles. The belt may be on the wrong side of a keeper.

First time changing the blades and I wanted to make sure that if I had a failure with my install it would be at lower speed if that makes sense. Once I determined it was OK I cranked it up and mowed for about 5-7 min and then the blades just stopped working altogether in the middle of mowing.

 

[Dionne Thacker]

I think you should buy a new mower then that would solve all your problems. LOL Just Kidding

Less than 30hrs on this one but hey, I'll consider it.

 

[Dionne Thacker]

New blades maybe bigger strain on the belt , might need a new belt, if it's squealing and it's tight, Get a new one

I suspected this might be the issue. I changed to blades originally because I hit a stump and literally one whole piece of a blade was missing on both sides of the blade (about 2" chunk)

 

[Dionne Thacker]

maybe a part damaged when lifting the mower for service? Like bent deck shell , etc. Look it over closely....

No chance. I lifted it using a specific jack meant to lift the unit and used only the front tires as a point of contact. I also used a 500lb impact to remove the bolts to ensure the blades didn't spin and then torqued the new blades to 110 ft lbs with a torque wrench after install. This is what is puzzling me so much. There was no incident at all with the remove and replace of the blades and the mower functioned perfectly all the way up to the last cut other than the blades being dull and needing replacement.

Crazy!

 

[Dionne Thacker]

I tightened the belt a little yesterday but the squealing kept happening. It sounds like it's coming from the rear of the mower rather than above the deck. The manual indicates the spring tensioner should be .025 - .030 (or about the width of a credit card). I checked it and there wasn't enough space between the spring coils to get .025 minimum so I tightened and test drove again. Minimal change if any. The only thing I can think of at this point is either a new belt (less than 30hrs on this one) or tighten it again and see if it changes.

The bottom line is that I cannot for the life of me determine how the hell this happened in the first place. The blade replacement went perfect and I torqued it to manual spec with a torque wrench (110lbs). I lifted the mower with a MoJack lift by the front tires only. There is NO chance I damaged the unit during lift

Anyway. all of that to say, it's a fucken mystery folks! I would love to know what I actually could have done differently because I actually need to mow my two acres today!

Thank you to everyone who responded so far, it really helps the thinking process to get different perspectives, even the smartass one that suggested I buy a new mower. Haha