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

I have a sm 420 sitting on the floor of the garage if you need me to take a picture .there is a metal clip on the nut if I am thinking of the same one

Thank you. I just corrected my original post. I do have that clip, but I’m having trouble getting the eccentric bolt to hold still so I can torque the nut to spec.

I looked at the two I have in the garage and the older one has a nut on both sides and the newer one has around ,with a flat side on the inside .maybe special tool needed

Here is the newer one

Maybe now here it is

Okay. I see the difference now. Mine is actually like the second one with the flat side on the inside

Okay got me motivated to get the old one apart it had some moisture as you can see here is the piece apart.

I see that the old ones have a spacer. Mine is the newer type with no spacer.