|
|
|
|
|||||
|
||||||
From: (no name) (no email)
Date: Wed Dec 01 2004 - 06:49:12 EST
Michael,
I guess I'd call the manufacturer first and ask. Unlikely you're the only one
with the problem. Is it always the same bolt that shears first? If so,
perhaps the holes in the pump (or the block) are drilled incorrectly, allowing
all
of the pressure to be exerted on the one bolt until it shears, following which
the second shears. Have you checked to be sure the belt isn't too tight? When
you replaced the bolts, were you careful not to exceed the max torque and that
the bolts aren't bottoming in their holes? Correct torque on a 5/16-18 Gr 5
bolt isn't much, and should be about 1/3 less if the threads are oiled. Of
course, you could just routinely replace them every year!
I don't think you should have to go to extremes with higher-grade bolts, and
certainly not SS, but you could try a grade 7 or 8. There's not much
difference between them, though, and the 7s are likely easier to find. Try a
Caterpillar dealer.
John
"Seahorse"
Michael Oritt writes:
I have an Onan MDJF 15 kW generator, the fresh-water recirculating pump to
which mounts on an angle bracket that is bolted onto the side of the block
with
two 5/16" coarse-thread bolts. The load on the bolts is in shear and perhaps
because of some vibration problem that is just what the bolts do: After a
year or so of service they shear off--first one goes and then the second.
I have just extracted the threaded sections out of the block. The last time
I used grade 5 bolts and I'd like to use something that perhaps is less
likely
to snap off. Are stainless bolts harder or do I need something in harder
steel? Or should I be using something in a more conventional grade (3 or 4)
that
might be less brittle?
_______________________________________________
http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering
To Unsubscribe send email to
Include the word Unsubscribe (and nothing else) in the subject or body of the message.
Trawlers and Trawlering, T and T, TrawlersandTrawlering, and TandT are trademarks of Water World International. Unauthorized use is prohibited.
|