63-82 Lower Rear Shock Nut - NCRS Discussion Boards

63-82 Lower Rear Shock Nut

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Edward J.
    Extremely Frequent Poster
    • September 15, 2008
    • 6942

    #16
    Re: 63-82 Lower Rear Shock Nut

    Thanks Rich, learned something new.
    New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.

    Comment

    • Chuck S.
      Expired
      • April 1, 1992
      • 4668

      #17
      Re: 63-82 Lower Rear Shock Nut

      Originally posted by John DeGregory (2855)
      ...So just what is the plating of the shock nut? Bare, zinc, cad or what?
      Meanwhile are you all saying that 63 to 82 rear shock hardware was all finished the same way?
      Rich's nice photo shows the nuts as being shiny.
      Joe Ray told me that on a 63 zincad was incorrect!!!...
      It's nice to be on the same side as Joe Lucia and Joe Ray on this issue.

      John, I bought a pair of these off ebay years ago...they were natural steel. The ones that came off my car were rust red, so they probably were never zinc either.

      Rich's pictures are shiny, but I believe it's because these are exceptionally pristine examples. He may have taken them out of original packaging for the picture (shame on you, Rich ). To my eyes, they are not shiny enough to be plated; it's just good old natural steel mill finish BRAND NEW. You can see darker spots on the surfaces that are either pits from the forming process, or very mild corrosion.

      As for dimensions, I think the important point is these ARE NOT the standard hex nut pattern...they are longer. However, before I concluded that a nut shorter than 0.715 is original, and not an early aftermarket replacement, I would have to find a shorter nut on a known original car, and possibly identify how the change occured over years. The parts spec is the parts spec...GM would not have changed it without reasons.
      Last edited by Chuck S.; March 18, 2010, 12:30 PM.

      Comment

      • Patrick N.
        Very Frequent User
        • March 10, 2008
        • 954

        #18
        Re: 63-82 Lower Rear Shock Nut

        Chuck,
        I'd be interested in what you and the others find on the small size issue, I have bunch and they all measure in the 0.6"ish range. it is interesting when the smaller nut is tightened the bolt sticks out beyond the nut just an odd little bit, but I chalk that up to aftermarket shocks / bushings.

        Pat

        Comment

        • Timothy B.
          Extremely Frequent Poster
          • April 30, 1983
          • 5186

          #19
          Re: 63-82 Lower Rear Shock Nut

          Thanks Rich,

          I must have had them mixed up, I remember now..

          Comment

          • Edward J.
            Extremely Frequent Poster
            • September 15, 2008
            • 6942

            #20
            Re: 63-82 Lower Rear Shock Nut

            Pat, I used the Delco replacement shocks on my 72 with the washers in place and the nut installed and there is no threads showing, The 70-72 JM calls for the nut to be flush with the end of the lower shock mount.
            New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.

            Comment

            • Chuck S.
              Expired
              • April 1, 1992
              • 4668

              #21
              Re: 63-82 Lower Rear Shock Nut

              Originally posted by Patrick Nolan (48743)
              Chuck,
              I'd be interested in what you and the others find on the small size issue, I have bunch and they all measure in the 0.6"ish range. it is interesting when the smaller nut is tightened the bolt sticks out beyond the nut just an odd little bit, but I chalk that up to aftermarket shocks / bushings...
              Actually, Patrick, I don't plan to do any research on shock nut lengths...I was merely saying what it would take to convince me that there ARE genuine GM shock nuts of shorter length out there.

              I am comfortable enough that the NOS examples I have will pass muster. I haven't actually mic'd either the originals or the NOS parts to know exactly what lengths they were, and I doubt the difference is enough to be obvious to a cursory judging glance.

              But...this does sound like a good project for someone that's convinced there are GM shock nuts of shorter length. The years of application of shorter nuts, if any, would be important...that would permit the researcher to begin to understand when change, if any, occurred.

              Comment

              • Alan D.
                Extremely Frequent Poster
                • January 1, 2005
                • 2038

                #22
                Re: 63-82 Lower Rear Shock Nut

                The cam adjustment nut is 3792930 and about 0.555 in hight while
                the lower shock nut is 3691530 and about what Joe listed 0.715
                So clearly these are not the same part.
                Last edited by Alan D.; March 18, 2010, 07:34 PM. Reason: Insert correct dim for 1530

                Comment

                • Alan D.
                  Extremely Frequent Poster
                  • January 1, 2005
                  • 2038

                  #23
                  Re: 63-82 Lower Rear Shock Nut

                  Rich & Joe - a little confusion here which may be due to a long thread.

                  If the nuts where changed from reg to locking to locking & course thread would GM still hold the same part number???

                  Also the support itself, 3820929/930 (regular susp) stayed the same from 63-78 when service replacements 3829265/266 were called for. So same question; why didn't the part number change when it went to course thread in 68?? Can understand if the mold deterioration was such that fine threads
                  were no long good then a change to course may have been an option.

                  So a little confused here, guess you can tell I never worked at GM.

                  Comment

                  • Joe L.
                    Beyond Control Poster
                    • February 1, 1988
                    • 43221

                    #24
                    Re: 63-82 Lower Rear Shock Nut

                    Originally posted by Alan Drake (43261)
                    Rich & Joe - a little confusion here which may be due to a long thread.

                    If the nuts where changed from reg to locking to locking & course thread would GM still hold the same part number???

                    Also the support itself, 3820929/930 (regular susp) stayed the same from 63-78 when service replacements 3829265/266 were called for. So same question; why didn't the part number change when it went to course thread in 68?? Can understand if the mold deterioration was such that fine threads
                    were no long good then a change to course may have been an option.

                    So a little confused here, guess you can tell I never worked at GM.
                    Alan------

                    I think we're mixing things up a little here. The nuts that were changed were the FRONT suspension upper cross arm-to-frame retaining nuts. The 63-67 used 7/16-20 fine thread; 63-E66 nuts were standard hex and L66-67 were locking style. 1968-82 used 7/16-14, all locking style.

                    The rear lower shock nuts were always 1/2-20 thread. As far as the shock mounts are concerned, there was no difference in the threads between the 2 different sets of shock mount shafts you mentioned. The difference in the 2 sets of mounts was an angularity difference and, possibly, a material difference. The angularity difference was to help provide more clearance for the F-41 shocks.

                    All 63-82 with standard suspension used the 3820929/3820930 shock mounts. All 63-82 with F-40, F-41, and FE-7 used the 3829265/3829266 shock mounts. After the mid-70's, though, only the 3829265/3829266 were available in SERVICE for ALL 63+ applications, regardless of suspension option.

                    As far as working for GM, I never did, either.
                    In Appreciation of John Hinckley

                    Comment

                    • Patrick N.
                      Very Frequent User
                      • March 10, 2008
                      • 954

                      #25
                      Re: 63-82 Lower Rear Shock Nut

                      Ed, I hear you, it should be flush, something is slighlty off in my setup, could be nut length, Monroe shocks, or washers or the nut behind the wrench - it will have be another detail I have to be happy with putting on the "address before judging" list- seems to be a growing list.

                      I'm always impressed by the knowledge on this site!!
                      Thanks,
                      Pat

                      Comment

                      • Alan D.
                        Extremely Frequent Poster
                        • January 1, 2005
                        • 2038

                        #26
                        Re: 63-82 Lower Rear Shock Nut

                        Thanks Joe! "I think we're mixing things up a little here"
                        Yes I was.

                        Comment

                        • Joe L.
                          Beyond Control Poster
                          • February 1, 1988
                          • 43221

                          #27
                          Re: 63-82 Lower Rear Shock Nut

                          All------


                          Well, I checked out the nuts a little more. It seems that I have 36 NOS examples of this nut [none for sale]. About 2/3 of them have no manufacturer's ID markings that I can see. The other 1/3 have the triangular "W" marking as shown in the photo below.

                          I also remeasured them. The first time I did a rather crude measurement. This time, since length seems to be such an issue here, I dug out the old Browne & Sharpe micrometer and measured about 15 of them. The GM spec for this nut calls for them to be between 0.677-0.697". Every one of the 15, or so, I measured was within that range. The shortest was 0.6770", right at the lower limit; the longest was 0.6970, right at the upper limit. All the others were between these 2 values.
                          Attached Files
                          In Appreciation of John Hinckley

                          Comment

                          • Edward J.
                            Extremely Frequent Poster
                            • September 15, 2008
                            • 6942

                            #28
                            Re: 63-82 Lower Rear Shock Nut

                            Joe, did you find the NOS shock nuts all natural steel? thanks Ed
                            New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.

                            Comment

                            • Joe L.
                              Beyond Control Poster
                              • February 1, 1988
                              • 43221

                              #29
                              Re: 63-82 Lower Rear Shock Nut

                              Originally posted by Edward Johnson (49497)
                              Joe, did you find the NOS shock nuts all natural steel? thanks Ed
                              Ed------


                              They are not natural steel, per se. The nuts all have a what appears to be a light gray or thin phosphate-like "coating". However, it's not really a coating. These nuts were hardened using either a cyanide process or a carbo-nitride process. That process imparts the light gray appearance.
                              In Appreciation of John Hinckley

                              Comment

                              • Edward J.
                                Extremely Frequent Poster
                                • September 15, 2008
                                • 6942

                                #30
                                Re: 63-82 Lower Rear Shock Nut

                                Joe, Didn't want to beat a dead horse, as the thread has. thanks Ed
                                New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.

                                Comment

                                Working...
                                Searching...Please wait.
                                An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

                                Please push the back button and reload the previous window.'
                                An unexpected error was returned: 'Your submission could not be processed because the token has expired.

                                Please push the back button and reload the previous window.'
                                An internal error has occurred and the module cannot be displayed.
                                There are no results that meet this criteria.
                                Search Result for "|||"