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Drive Shaft bolts, anything special?


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I am replacing the U joints on my 1966 C Model fire engine. The Short shaft between the 5 speed tranny and the pump tranny has 8 hole flanges on either end the bolt to the Tranny's. When I was removing the shaft one bolt was missing from each set of flanges and the others were not very tight. I would like to replace all bolts with new ones. Are they a special bolt or can I use a standard bolt, grade5 or grade8. I know they are 3/8 " fine thread, and I am not sure but the shoulder portion of the bolt may be a little longer to allow the flanges to not "bear" against the threaded portion to the bolt were it may be weaker. Also does any one know if there is a recommended torque value for these bolts? Thanks guys.

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Not seeing what you have there, can't tell about head size on bolts.

There are flange bolts available from industrial supply stores in 3/8 fine. Take one out and see how it might match up. If the bolt head has three lines on the top it is grade 5.

Grade 5 should be ok in that application. 25 lbs for torque. if you go with Grade 8 bolts, 35 lbs.

A little medium strength threadlocker wouldn't be a bad idea.


It doesn't cost anything to pay attention.

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I always went back with gr8 bolts for driveline, of course most of the drivelines I've been into were heavy spec with 1/2" bolts.

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