Mower deck Breaking deck leveling bolts

I have a courier with the 52 inch deck. I have replaced the the deck leveling bolts 3 times now in the 2 years I owned it. I'm the first owner and this is a good machine. This year first time out mowed about half my front yard got off to put gas in it and the left side of my deck was dragging dirt. Was not broke when I pulled up to park it but was when I got on. Never hit anything never caught anything but it was broke all the same. This does not have the chains like a normal deck leveling system this has the long bolt with a large hook on the top to wrap around the shoulder bolt. Little to no play in the side to side of the deck. Does anyone else have problems with these breaking?

Wonder if it has something to do with the suspension system on that mower.

https://www.simplicitymfg.com/na/en_us/product-catalog/zero-turn-mowers/courier-zero-turn-mower.html

P.S. - I'll check with my Bob-Cat dealer next time I'm there and see if it's a common problem and if they know of a solution. They're also a Simplicity dealer and sell the Courier I know. Won't be any time real soon though.

Darryl G said:

Wonder if it has something to do with the suspension system on that mower.

P.S. - I'll check with my Bob-Cat dealer next time I'm there and see if it's a common problem and if they know of a solution. They're also a Simplicity dealer and sell the Courier I know. Won't be any time real soon though.

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Thank you for your reply. Any help would help. I'm not the only one who mows with mower. My daughter last year scalped a couple row of grass before she realized it. I'm thinking about just switching over to the chain system. Might not have the same even cut but might help scalping the yard. Just need to find out more to be able to do it.

I read reviews on the Courier and there are quite a few complaints about scalping due to the suspension system. If it's scalping that means the deck is contacting the ground. I suspect that it's contact with the ground that's causing the issue of the bolts breaking.

Is that suspension adjustable? If so, perhaps you could stiffen it up a bit?

It does seem like it's asking a lot of those bolts to suspend the deck. They're not very big. You may end up with other issues if you modify it to hang on chains.

Looking at the picture of the bolt that is a shear break, not a pull break. That means that forces are acting on the bolt through the threads, not with the threads. The deck is hitting on something not being pulled down.

Darryl G said:

Wonder if it has something to do with the suspension system on that mower.

https://www.simplicitymfg.com/na/en_us/product-catalog/zero-turn-mowers/courier-zero-turn-mower.html

P.S. - I'll check with my Bob-Cat dealer next time I'm there and see if it's a common problem and if they know of a solution. They're also a Simplicity dealer and sell the Courier I know. Won't be any time real soon though.

Click to expand...

Just a follow-up. I talked to my dealer last week and they haven't had any failures on the machines they've sold. The deck is obviously hitting something. Perhaps someone is just operating it too fast on uneven terrain? If it's a repeat occurrence there's probably a problem area in your lawn that catches the deck.

BlazNT said:

Looking at the picture of the bolt that is a shear break, not a pull break. That means that forces are acting on the bolt through the threads, not with the threads. The deck is hitting on something not being pulled down.

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Or a fatigue fracture due to vibrations while the deck is running.
Vibrations do not need the deck to be hitting something.
If the hanger bolt is in tension from the weight of the deck then the hanger is being stressed in 2 planes which drastically reduces the fatigue life of the hanger.

Any further diagnosis of the hanger will require some high resolution photos of the fracture surface.
As it has also fractured through the thread root, the thread may have been badly cut with too sharp a root which becomes a crack initation point.
The bolt also shows fretting signaling that it has been hitting something fairly regularly.

If the D bolts on JD decks are put in backwards a similar fracture can happen.

A D bolt puts a bending moment on the shaft by virtue of the fact all of the weight is on one side of the bolt.
If the bolt is subject to flucuating loads along its length for example slightly more load as the blade swings past then a decreased load till the next side passes you will be getting a fatigue cycle 2 x blade speed.

So the whole thing could be nothing more than an out of balance blade, either in weight or airflow or both or a slightly bent blade or using a different blade from the one it was designed for , or running the blades too fast.
There are a myriad of factors that have to be considered in a proper failure analysis.

I agree with Bert on this one, looks like the hanger is mounted backwards. Had this problem on a JD a few years ago and the customer was putting one hanger one way and the other side the opposite.

There's a photo of it on the mower in my first reply. I tried to post it individually but the system doesn't like the file extension.

I think the deck is hitting the ground based on the large number of complaints about scalping in the reviews for his model and having gone through 3 sets of bolts in 2 years.

That bolt should be mounted so the open end of the d is facing forward. It should have some play front to back and very little play side to side. Two questions, one does the same side always break and two how close to the leveling block is the break?