Join Date: Oct 2016
Location: Tellico Plains, TN
Bolt failure on Alternator mounting bracket
Yes we had a hardened bolt failure. A microstructure fracturing propagated by a natural thread root stress riser is the culprit. The shoulder length of the bolt failed to extend into the engine block counter bore which would have greatly reduced mounting face movement frequency. A cardinal design sin... Yes the bolt is what Polaris calls for and it was installed by the Dealer.
Having some left-handed carbide drill bits, I attempted to remove the broken bolt end. As you can see even stepping up the size of the bits would not disengage the broken end threads.
The dealer had to pull the engine in order to get the engine block on a machining center to perform a salvage proceedure?.
Might want to have a look at yours..