I have had this happen several times on one of my trucks. In my case it threads into a blind hole on a bracket. It is fine thread so has to be a grade five or grade eight. Grade eight is much easier to find than a fine thread grade five. After way too many broken bolts I found that a grade eight bolt will easily fracture IF NOT TORQUED TO SPEC.
Eleven years ago I torqued it to spec and haven’t had one break since.
How many broke? On one cross country trip of about five thousand miles I think it was four broken alternator pivot bolts.
I assume they were over torqued when they broke?
Under torqued. Just snug with a wrench.
To get the strength rated, the bolt has to be tightened to the torque value, less will allow it to break.
If this is the "stock" Sherwood brand pump, I recommend changing it out for a new SMX 1730 pump from Seaboard Marine (sbmar.com). It is a far superior pump in almost everyway, and does not cost much if any more. It is a "plug and play" or direct fit. It comes with an impeller puller as well, making impeller changes easier.
The new cam that broke the bolts allows the bolt to pass through. The old one bottoms out.
When the bolt is bottomed out in the old cam it doesn't move laterally. The new one move side to side a small amount. It may be vibrating and break
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We did re-use the old cam.If the cam moves it will break the bolt. The old cam looks ok is there any reason not to re-use it ? Unless it is overly thin I would suggest using the old cam. The bolt should only retain the cam and not be under any additional load, if the new cam is moving you have a problem and the bolt will fatigue.
WELL IT HAPPENDED AGAIN!!!
We are going to change the pump with a Seaboard. We need to jack the port mount up. Where do we place the hydraulic bottle pump and how do we support it. I havent look at his boat yet, just sbmar Tony Tips review. Need a little help