REFLECTOR:Alternator Woes.

[Scott Derrick]

My alternator has been a constant pain in the ass since I bought the plane.

1.)  Bolt came out that holds the adjusting arm bracket to the case. 
Why?  It was not safety wired, no hole on the bolt head. It went through 
the prop on the way out, no major damage.

2.) The adjusting bracket cracked after 75 hours. This is the long 
bracket with the slot in it.  I replaced it with another of same make 
thinking it must have had a flaw.  No damage to plane.

3.) The new adjusting bracket cracked after 45 hours. This bracket is a 
universal replacement chromed bracket.  It was crap.  Poor grade of 
steel and chromed on top of that which weakened it even further. I 
questioned replacing it when I did it but didn't trust my instincts. I 
scavenged a junk yard for a good quality bracket. No damage to plane.

5.) After installing new bracket alternator still wiggled. The multiple 
mounting failures had caused the lower pivot mounts to wear elongation's 
in the mounting holes.  I reamed them out on the mount and alternator 
installed 7/16 shoulder bolts.

4.) The alternator failed.  Disassembled it and decided that this 
particular unit had seen 300,000 miles of service before installation on 
my airplane. Didn't know what the unit had come off of and my local 
alternator shop found a new replacement.  No damge to plane.

5.) One of the 7/16 shoulder bolts failed.  It was mislabeled in the 
store as a high alloy steel, it was garden variety.  I probably over 
torque'd it thinking it was a better bolt but it should never have been 
used in that application anyway.  It went through the prop on the way 
out and wholloped my Catto prop real good in 4 places(nut and 3 
washers).  My A&P buddy thinks it happened on the ground and the fourth 
whap near the tip was one of the pieces bouncing back up into the prop. 
  I'm replacing the  failed and remaining bolts with true 7/16 grade 8 
bolts.  Also repairing prop.

All these failures can be attributed to "Pilot Error" in my opinion.

No safety wire on a bolt.
Using inferior bracket.
Using junk yard alternator of unknown age.
Using substandard hardware.

Scott