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blades on a deere riding mower hitting the shroud

Posted by bigedgar (My Page) on
Sun, Jul 25, 10 at 21:04

Hi,

We ran over a small stump with our John Deere LA120 the other day which was a bad idea. Now when we engage the mower assembly and the blades start spinning, both blades hit the side of the shroud assembly (or whatever you call the metal cover that covers the blades) as they spin. We got a new set of blades hoping that the blades just got warped, but alas the problem persists even with a new set of blades.

Our guess is that the shafts that hold the blades got bent. Seems odd to have them both go at once, but maybe that's what happens when you hit a stump.

Two questions:

1) Does a bent shaft seem likely to be the issue here? Are there other possibilities we should consider?

2) We live about 50 miles from the nearest service shop and don't have a truck to transport the mower. Is it possible to remove the mower assembly (which we could fit into a car) and just bring that to the shop? Or are they likely to need the whole mower?

Obviously we'd like to get this fixed as cheaply as possible, and we're pretty handy so we can do some work on the mower ourselves to save some $$. Thanks for any thoughts!


Follow-Up Postings:

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RE: blades on a deere riding mower hitting the shroud

As the shop of your choice may well need the correct tractor model at their shop to run your mower deck, would give them a call first - let them know what you've got that needs fixing - to avoid a long trip for nothing .
Yes, you should be able to transport the deck only in the trunk of your car.


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RE: blades on a deere riding mower hitting the shroud

Yes, you need the deck removed from the tractor. Then, you need to prop the deck up against something secure that does not touch any pulleys on the deck.
Now, you can move the blades by hand and watch what is hitting what.
Here's is what you need to look for.....and why.
If only one of the blades is hitting the deck shell, and both ends of the same blade hit the same spot....either the deck shell is dented or warped inward at that spot, or the deck shell where the spindle assembly fastens to the top of the deck is bent/warped.
To tell if it is the top of the deck where the spindle mounts, you will need to lay a straight edge across the bottom edges of the deck spanning from front to back of the deck (you may want to turn the deck completely upside down across some saw horses for this).
With the straight edge across the centerline of the blade attaching nut, and the blade oriented along the straight edge, take a ruler or tape measure and measure from the straight edge down to the tip of the blade. Write the value down. Now go to the opposite tip of the blade (move to that side of the deck, do not move the blade). Measure from straight edge to blade tip. Write down the value. Compare the 2 values. If the difference between one blade tip and the opposite is greater than 1/8", the deck is bent on top where the spindle mounts. You can double check to see if the blade shaft is bent while you have the straight edge by simply rotating the blade so that the blade tips are at opposite side of the deck and remeasure the values again as you did the first time. If the values remain the same for both tips, the shaft is straight. It is possible to bend a deck and a shaft, but the very first check where you look to see if both tips of a blade hit the exact same spot of the deck shell should have told that.
Now........if both blades are striking the deck in similar fashion, I would have to wonder if you bought blades that are too long! But it is possible that the entire leading edge of the deck shell (front skirt) has been bent backward seriously enough to cause both blades to strike the skirt. By the way, blades are measured for length across the diagonal using the trailing edge of the blade tip as the measuring point (not much wear there, and the diagonal is the true diameter point when the blade spins).


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RE: blades on a deere riding mower hitting the shroud

Wow, that was fast!

Thanks to both of you for the thoughts. Mowie - we'll take your advice to start with and do what you've recommended. RCBE - if we need to take it in, we'll make sure we have the info you mentioned.

Mowie - I'm sure we got the right blades, as we had a similar issue recently where one of the blades hit a rock and one of the blades warped (we are mowing a pretty rough field with this mower and after two years of no problems, we struck lightning twice in a month). Buying new blades fixed the problem... until we hit the dang stump. Anyways, it was easy to buy the blades this time around since I had purchased the right ones recently for the rock incident.

My brother in law is up at our place with the tractor this week, I've sent him your suggestions and will let you know what we find out.


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RE: blades on a deere riding mower hitting the shroud

Dignostics via cyberspace ain't the same thing as seeing it first hand. And exchanging dialogue can be a waiting process. So, sometimes I will toss in details or circumstances that MIGHT be applicable, or not, to the issue at hand rather than waiting for negative results and having to offer further details later. And thanks for confirming you are in fact using the correct length blades. Please post back what BIL finds. :^)


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RE: blades on a deere riding mower hitting the shroud

Remove deck assembly-turn upside down--find where blades are hitting deck! Then, using a BFH, smack the deck area outward, where the blade is hitting the metal! Turn blade mandrell shaft, to make sure blade has a half inch of clearance. Lay new blade on an old one, make sure they match. If so, reassemble the deck and blades, re-attach the deck to the tractor, and go mow!
Oh, what is a BFH?? A large hammer, usually used for beating heartily on anything you want to straighten, ruin, break, or whatever!
Jus a suggestion from a VOF! And, this sage advice will save a lot of hassling with some SA service manager!


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RE: blades on a deere riding mower hitting the shroud

Fixed! My brother in law pulled the mower assembly per Mowie's suggestion and found 1) that only one blade was striking the shroud, and 2) it was due to a metal piece near the grass ejection hole in the shroud that had bent. Not what I was expecting, but it's 90 minutes of my BIL's labor for a fix. And that makes it free to me!

Thanks again for the help!


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RE: blades on a deere riding mower hitting the shroud

Fixed! My brother in law pulled the mower assembly per Mowie's suggestion and found 1) that only one blade was striking the shroud, and 2) it was due to a metal piece near the grass ejection hole in the shroud that had bent. Not what I was expecting, but it's 90 minutes of my BIL's labor for a fix. And that makes it free to me!

Thanks again for the help!


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