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What was the original configuration for 1970 front shocks regarding the upper bolts? The new GM shocks I am installing came with a modern 9/16" hex nut and a 9/16" hex lock nut. The hardware that I have removed from the old shocks consisted of two 11/16" hex nuts for each shock.
First of all, when describing the size of bolts or nuts, the conventional system uses the diameter of the actual threaded portion of the fastner, not the size of the head across the flats(socket or wrench size). Second, there are no shock upper bolts. The upper shock on all 63-82 Corvettes uses a 3/8"-24 threaded shaft which is retained by a single hex head nut. This nut, GM #1365067 and long-ago discontinued, was a 3/8"-24 nut of 5/16" thickness with phosphate finish.
On the lower end, the shock is retained by 2 bolts. They are an indented head hex bolt with a captive conical spring washer. Size is 5/16"-18 with a total length of 7/8" and a threaded length of 5/8". They have a phosphate finish.
First of all, when describing the size of bolts or nuts, the conventional system uses the diameter of the actual threaded portion of the fastner, not the size of the head across the flats(socket or wrench size). Second, there are no shock upper bolts. The upper shock on all 63-82 Corvettes uses a 3/8"-24 threaded shaft which is retained by a single hex head nut. This nut, GM #1365067 and long-ago discontinued, was a 3/8"-24 nut of 5/16" thickness with phosphate finish.
On the lower end, the shock is retained by 2 bolts. They are an indented head hex bolt with a captive conical spring washer. Size is 5/16"-18 with a total length of 7/8" and a threaded length of 5/8". They have a phosphate finish.
Joe, Thanks for answering my poorly worded question. The nuts' external appearance and dimensions are what interest me the most. I have two different sized hex nuts with the 3/8-24 threads, 9/16" and 11/16". I'd like to choose the ones that are most like the original in appearance. If neither is close, I'd like to know what to look for at the hardware store or junk yard on my next visit. Additional help is appreciated.
Joe, Thanks for answering my poorly worded question. The nuts' external appearance and dimensions are what interest me the most. I have two different sized hex nuts with the 3/8-24 threads, 9/16" and 11/16". I'd like to choose the ones that are most like the original in appearance. If neither is close, I'd like to know what to look for at the hardware store or junk yard on my next visit. Additional help is appreciated.
Tony The hex size is 9/16 full hex for the 3/8 fine thread nut. The nut should be very flat on each end, that is no chamfer. The male thread is also peened so the nut will not back off on original assembly line build. This feature is all most never judged.
Tony The hex size is 9/16 full hex for the 3/8 fine thread nut. The nut should be very flat on each end, that is no chamfer. The male thread is also peened so the nut will not back off on original assembly line build. This feature is all most never judged.
OK, Tony, now that you've got the right nut, don't forget the washer at the top of the shock. The correct washer is 1 7/8" in diameter and has a gray finish. It might still be available from GM. I bought a pair not too long ago. The original P/N was 3790342.
Also, the bottom bolts for your car DO NOT have lock washers. The P/N for the bolt is 3968521. Just like the line clip bolts, this one has a washer head, no washer, and is finished black oxide. Be careful and not over tighten them. They are easy to strip.
OK, Tony, now that you've got the right nut, don't forget the washer at the top of the shock. The correct washer is 1 7/8" in diameter and has a gray finish. It might still be available from GM. I bought a pair not too long ago. The original P/N was 3790342.
Also, the bottom bolts for your car DO NOT have lock washers. The P/N for the bolt is 3968521. Just like the line clip bolts, this one has a washer head, no washer, and is finished black oxide. Be careful and not over tighten them. They are easy to strip.
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