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Snapped bolt on mower spindle 318

4175 Views 11 Replies 10 Participants Last post by  aratki
I hit a root this morning and snapped the bolt holding the blade on, I also snapped two carraige bolts holding the unit to the deck. how do i get everything apart to replace the carriage bolts, and how do I get that bolt out of the spindle?
should i just replace the unit? I have a 318.
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Usually, you can use a pick and turn out the broken piece out of the spindle. I have done it that way. If that won't work, drill a hole in the broken bolt and use an "Easy Out" extractor to remove the broken bolt.
You may have also bent the deck when the spindle housing got tweeked. The last carriage bolt nut can be accessed from the underside of the deck. If the deck it bent up, some heavy washers, a nut and bolt and an impact wrench can be used to true it back up.

For the spindle bolt, you "might" be able to smack it with a really small cold chisel and get enough bite to turn it out with the chisel. Otherwise Kevin is correct.

You will need to drill a pilot hole in the bolt and use an "easy out" (there's an oxymoronic name eh?) to get it out. Start with a larger, stiff drill bit to try and create a centering depression in the bolt and then go back with the small bits and work up to the size you need for the easy out. If you start with the small stuff you will end up walking the bit to the edge of the bolt and gumming up the threads....

Not that I have any experience with either of these issues...;-)
Also, if you have a welding, you can weld a nut where the head of the bolt was.
You weld inside the nut on top of the remaining bolt.
If the bolt is flush with the spindle, use a smaller bolt to avoid welding the thread.

When a bolt break when you try to unscrew, they are a pain to remove.
When they break like your's usually they are easy to remove because they don't break because seized.
If you have to drill like Kevin said, left hand drill bit are the best.
The bolt might unscrew while drilling.


Find someone with a lathe. Much easier to drill it out on center and remove the old threads. These bolts usually have to be taken out with an impact and it may be in there too tight to remove by other methods. But then again, it just may.

be sure to use a grade 5 bolt. It is the week point in the spindle for a reason. A grade 8 may not break but something else will.

Have you fixed you spindle bolt problem yet?

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I haven't touched it, We have family visiting, so its sitting on my work bench... but thanks for all the info, Looks like i'm buying an easy out.
after you get the hole drilled. Do Not pound the ez out into the hole. This will cause the bolt to mushroom out and lock it in place.

Like Tom, I dont have any experience with this issue :-(
Like Andre said use a left handed drill bit.

I first spray down the bolt with WD-40. If you still have a couple of days before your project keep soaking it with WD-40, it will help. Then I use a center punch to put an indentation in the center of the bolt. Get the largest bit that will not mess with the treads but make sure it is new or freshly sharpened and drill away.(Note- be careful the drill bit heats up quickly and has a tendency to break, make sure you have extras.) Next I take the extractor and remove the bolt. (Note- let the extractor do its job, don't force it.) This always works for me.
Jason, when you replace the bolt, put some never seize on the threads. It makes the second time easer to remove the broken bolt. I have small cedar stumps (they never rot out)in my yard and hitting one with the center blade on my 318 will shear the blade bolt.
One other thing. When you remove the spindle housing from the deck, it may be easier to tighten the carriage bolts rather than loosen them because if you loosen them, the shoulders on the bolt are not tight enough to keep it from turning in the housing. Then you cannot get anything to hold the bolt.If you tighten it, it will twist the bolt off.
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