The Stovebolt Site Forums The Shop Area Driveline SM 420 Reverse idler adjustment

I’ve done the search, but haven’t found this issue discussed in depth. I rebuilt my SM 420 in my 57 Chevy 1/2 ton using a Novak kit. My factory manual says to adjust the reverse idler eccentric bolt so there’s no interference with the other gears or the rear of the case. Then I tried to torque the castle nut to 40 ftlbs while holding the slotted bolt in place with a screwdriver. I broke the eccentric bolt, but found another so I can try again.

My question is: should there be a lock washer or something else I’m missing in the eccentric assembly so that I can torque it down? I’m thinking the nut has to be tight so the eccentric won’t go out of adjustment. I do not have the wire lock in place while I’m torquing the nut.

Thank you for any suggestions,

Larry