I have a 91 Camaro RS, with a 305 and a 700R4 tranny. The previous owner replaced the alternator and left off a bolt. The missing bolt was connected to a black rod that runs down by the exhaust manifold. It is the bolt on drivers side of the alternator.

I keep getting an over voltage code, and I think this bolt is the reason. Could anyone please tell me what size it is? Autozone and Advanced Auto both say they can't look it up.

Thanks for any help.

 

3/8-16 x whatever length you need

 

Bought that bolt... It was way too big.

 

I doubt that your DTC is related to a missing bracket bolt, unless the alternator is not gounded through the other mounting bolts. I'd be checking the voltage regulator and rectifiers.

 

The alternator has supposedly recently been replaced, and it does look really new. I think you might be right about the ground bit.

 

Not sure on the size but the head is 10mm. My 92 doesn't have that bracket and I don't have any voltage problems. I doubt that bolt is causing your problem.

 

Found the bolt size...
M8x1.25x25
Part Number 11509843

Hope this helps someone else down the line.