16 HP Briggs Head Bolt Question

[Horvik 37]

Hello;

 

I recently acquired a used 326431 0133-02 mill and noticed two of the head bolts under shroud flywheel side were loose. Of course it was loosing compression from this. I removed the head, measured the bore while at it, but all looked good.

My question is why did those bolts loosen, and what type of washers ( lock, flat?) are supposed to be there prior to torquing them down?

Thanks 

[jlasater 338]

If they are torqued properly, they won’t come loose.

[PhanDad 3,825]

16 hours ago, Horvik said:

what type of washers ( lock, flat?) are supposed to be there prior to torquing them down?

Head bolt washer is Briggs part #691261.  It's not a "lock" type washer; I have no idea if it's special or not.  

16 hours ago, Horvik said:

why did those bolts loosen,

Overheat; improper torque. 

 

[Bill725 1,364]

Use new 5/16-18, grade 5 HHCS with new grade 5 or better 5/16" flat washers. Lube threads with anti-seize, torque to spec and sequence shown in service manual.

Edited November 18 by Bill725