slspacek Posted April 4, 2013 Share Posted April 4, 2013 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. Quote Link to comment https://www.bigmacktrucks.com/topic/30680-drive-shaft-bolts-anything-special/ Share on other sites More sharing options...
j hancock Posted April 4, 2013 Share Posted April 4, 2013 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. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/30680-drive-shaft-bolts-anything-special/#findComment-176022 Share on other sites More sharing options...
slspacek Posted April 4, 2013 Author Share Posted April 4, 2013 Bolt heads are 9/16, standard for 3/8" bolts. Havn't cleaned all the muck and road dirt off yet, would think they are probably just grade 5. Will post a pick soon. Quote Link to comment https://www.bigmacktrucks.com/topic/30680-drive-shaft-bolts-anything-special/#findComment-176054 Share on other sites More sharing options...
rsb502 Posted April 11, 2013 Share Posted April 11, 2013 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. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/30680-drive-shaft-bolts-anything-special/#findComment-177296 Share on other sites More sharing options...
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