[The Ape Man]

When the distributor machanical advance gets stuck on these engines the culpret is not the weights and pivots. The binding occurs between the long shaft which is attached to the weight's hub whose other end goes all the way to the cam drive pinion and the outer hub on the top of the distributor who's inner diameter is only slightly larger than the shaft that it centers on. Hope this makes sense. The point is that the proper fix is to pull the distributor and clean everything then reassemble with lubricant that will keep working. I usually just take the fast route and bathe the hub with WD-40 while working it back and fourth. Most times this works. I then spray a little fast drying solvent like brake parts cleaner into the distributor to get rid of all the stuff. When taking the quick route it will be necessary to keep an eye on the thing as it will get stuck again sometime. Dunno if any other GM products ever had this problem. Maybe the Cad distributors were built with tighter tolerances and it resulted in binding.