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Spindle Bolt Sloppy

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#1 aariel OFFLINE  

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Posted August 21, 2013 - 02:44 PM

Having an interesting problem and can't imagine I'm alone.


I have a 54" mower deck with aluminum spindle housings. I had a hard time getting them removed from the deck because the nut had rusted and the bolt would spin in the square hole of the housing. Only 4 bolts had this problem.


Went to the dealer and ran into two mysteries.


#1 The JDParts Catalog specifies 03M7186 which is an M8 x 30 carriage bolt with a 3mm neck! That's a sheetmetal bolt. The old bolts have a 5.6mm neck. So either the part number is wrong in the catalog or the engineers decided that a 5.6mm long neck was a problem and a 3mm long neck was the solution.


#2 As a sanity check we pulled a brand new spindle and bolt and the slop in the square hole in the spindle and bolt is that same as my old spindle and bolt. So it's by design.


The slop is so bad if I over tighten the nut, or re-use the old nuts the bolt just spins.


I'm planning on tightening up the slop somehow. Probably just drop a couple of 3mm split lock washers in the gap between the bolt shoulder and the square hole in the spindle as I have these on hand.


So the question to the forum is, why is there so much slop in the square hole in the spindle? Is it for thermal expansion? Is it so the spindle can withstand shock loads? It sure makes regular service a giant PITA.



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#2 hamman OFFLINE  


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Posted August 21, 2013 - 03:07 PM

Have you tried to locate a SAE bolt and nut that would fit it tighter? Even if it was a bit bigger with some time and a grinder (bench mount) you might be able to make it fit tight enough to work. JM2CW. Roger.

#3 JDBrian OFFLINE  


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Posted August 21, 2013 - 06:51 PM

8mm is just slightly larger than 5/16 so you'd have to go to 3/8 to get a larger SAE bolt. That may be too big!

#4 aariel OFFLINE  

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Posted August 22, 2013 - 08:24 AM

Yeah 3/8 is too big. I would need an 11/32 carriage bolt. I think I would have better luck tracking down an M9 x 30 carriage bolt. Which is actually pretty common outside the US. But all this seems silly. Why are the Deere engineers specíng so much clearance? Or maybe manufacturing is just getting it wrong? The change from a 5.6mm neck to a 3mm neck is a head scratcher.