Alternator bolts keep snapping!

[Dodgerdavn]

Hello!,<br /><br />I have a '99 Reinell with a Volvo-Penta 4 cylinder engine. I bought it with 50 hours on it at the beginning of the summer. I am having a problem with the lower alternator bolt keeps breaking. Whoever had it before me had the same problem, as there was a broken bolt and washer in the transom. I have since put in 3 bolts in the last 25 hours. I am putting in a long bolt that goes throught both the alternator brackets, and putting a couple of washers and a nut at the end. At the rear bracket, it is threaded, so I thread all the way through, and then put on a nut. Where it exits the rear of the bracket is where it is snapping off. Any ideas on what could be wrong? With the engine running, it looks like the alternator pulley is straight. I am at a loss!<br /><br />Thanks for the help!,<br />Dave

 

[Trent]

Re: Alternator bolts keep snapping!

Are you putting the proper grade bolt in, would be my first question to you?

 

[Northern Eclipse]

Re: Alternator bolts keep snapping!

The pulley has to be running straight if it was off some you would be spitting belts, I would look to see if the bracket itself is strong enough, being a 4 banger they tend to be a bit rough at idle causing some vibration, is it possible the bracket is flexing a tad, but not enough to spit the belt, or is the bolt being over torqued??.

 

[oldboat1]

Re: Alternator bolts keep snapping!

If I understand correctly, the bolt that breaks is the one you are tightening down after adjusting belt tension. I can't quite figure out why it breaks at the point you describe. If you are putting a nut on the end after the bolt is threaded through the bracket, I would replace the bolt with a stainless steel one and use a washer and lockwasher at the head of the bolt -- without putting a nut on the other end. It sounds like you are overtightening the nut, and I don't think a nut should be used there anyway.

 

[Dodgerdavn]

Re: Alternator bolts keep snapping!

Hello again,<br /><br />Thanks for the quick replies. It's the lower alternator bolt that is breaking, not the top one with the adjustment. It's the lower fixed bolt. I tend to think I need a short bolt that does not go all the way through the lower bracket, one that does not require a nut at the end. Just one that threads into the bracket. Any more input would be appreciated!<br /><br />Thanks!,<br />Dave<br />

 

[llerrad]

Re: Alternator bolts keep snapping!

Check the grade of bolt you are using. Should be GRD 5 or 8. Only excess vibration will bust the bolt an additional support bracket could help.

 

[snapperbait]

Re: Alternator bolts keep snapping!

I agree with llerrad... Get a grade 8 bolt (gold cadnium colored)..

 

[eagleV]

I used grade 8 bolt n they keep snapping too

 

[GA_Boater]

I used grade 8 bolt n they keep snapping too

Thread is 17 years old!

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