I have a 1954 Willys Aero. It has 4 lug wheels with 4-1/2" spacing. I changed out the rear end to a Chevy Monte Carlo. I would like to re-drill the front drums to a 5 on 4-3/4" pattern. When I lay a jig on top of the drum, it becomes necessary to re-use one lug position which requires elongating the hole slightly. The other 4 lugs can be drilled into the drum without interferring with the old lugs. How do I handle the elongated hole? Do i weld up the old hole prior to drilling the new hole that will mostly fill the same space? Thanks for the help.
I would fill and re-drill the oblong hole could cause a problen with balance. But before I did that I would do some research to see if there were any drums available that were the proper size with the bolt pattern you are looking for Gary
Fill and drill. But do not use a bolt pattern gauge as a guide for relocating the new bolt pattern. Get a machine shop involved that has a rotary table for their Bridgeport type machines. A rotary table will accurately place the bolt pattern adccording to the true center and the bolt circle will be accurately located along with the spacing of the holes. Frank
Have you thought of getting a wheel adapter for it ? Then you don't have to re drill and pray that you did it right .
Adapters cost about as much as it will take to have it done right. Besides, I always wondered about the safety of 4 to 5 adapters.
Definately better to re-drill rather than addaptors, I presume that the drum and the road wheel are both located by a spiggot on the hub, So the holes in the drum are clearance on the studs. I probably would not worry about filling the old hole, the out of ballanced caused by a hole at only a small distance from the axis is not significant on something that heavy like a brake drum and the weld putting stress forces in to the iron is likely to give more problems.