Axis Wakeboard Boat Forum

Those of you with LS3's or anyone in general, check you alternator bolts! I talked to the dealer, and they had another LS3 with the alternator bolt broken. The bolt broke right at the surface of the block. I have done some research and found out it was a common issue in the older indmar's, but I haven't been able to fin any info on the newer engines.

It looks to be a stainless Steel bolt into an aluminum block. Old malibu threads suggested that I could be either a faulty batch of bolts or even too long of a bolt, causing the alternator bracket to vibrate against it. Either way, Im stuck with broken threads in the block.

Do you all think I should just tackle the job myself, hoping the broken bolt threads come out easy? OR just take it to the dealer and hope they don't keep my boat for weeks? The only thing I am worried about is corrosion on the the threads causing it to be seized. Otherwise, there is no pressure on those threads so it should back out easily.

My plan would be to order some grade 8 or even an ARP brand bolt of the same size.

If your gonna try it get a good center punch and hit that thing dead center. Then go after it with a reverse drill bit, most of the time the bit will spin it right out. If the bolt was too long as you suggested its gonna be a bear because it hit bottom and someone torqued it good. Most important thing is a dead center punch( even a little off will get out of hand quick) follow by smaller drill bits working to larger. Take your time, hard to do but you will regret it otherwise. Good Luck

You can also spray some PB Blaster on the bolt if you think it may be seized.

I restore a 73 Camaro and every freaking bolt are seized/rusted/rounded. And if I spray PB Blaster a few days before working on it, most of then come out pretty easy.

Pfewwww. Bolt came out super easily. It's a metric 10 size bolt so I had plenty of room to mess with. I ended up using a punch to punch to holes, opposite of each other, on the outer edges of the bolt. I then just took two picks and started spinning the bolt out. It was barely even finger tight.

Anyway, to prevent it from ever happening again. I went and bought a stainless steel ARP head bolt that was the correct size. I believe the size is M10-1.50x80. Needless to say, if the arp bolt breaks, I have something major going on.

I just snugged it up, but I am trying to search for the correct torque specs for that bolt since it does thread Into the aluminum block. I've found everything from 18 ft/lbs to 37 ft/lbs. anyone out there have experience working on aluminum engine blocks and have a better idea of what torque spec to use?

For that size bolt into aluminum your looking at about 35 ft lbs. I would suggest putting some anti seize on the threads.

I wouldn't go over 40-50 max, but instead of anti seize I would probably put a small dab of silicon on the thread so it sticks in there, I do it all the time on exhaust bolts for cars with headers and have never had one fall out since.