Packard Forum Index » Pre-War (1899-1942)

I want to rebuild the master cylinder on my 1936 120 without damaging the knurled edge of the plug. Years ago, I would simply use a pipe wrench when rebuilding
a master cylinder in an old car but now I want to avoid damaging the knurling. Was there a special wrench made for this and if so, where would I find one? Could
I wrap the part in copper sheet to avoid damage? Any suggestions would be appreciated.

cut some 1/2" wide very long strips of aluminum tin foil and wrap the knurl about 10-12 times...then (best to use a Knipex brand) gently grasp it with a channel lock (not vise grip) and the aluminum will be sacrificial and compress into the teeth of the knurl and those on the channel lock jaw. GENTLY, rotate...if your sensing it is slipping or going to damage the knurl, do a test grasp, then remove the wad of foil wrap and inspect to ensure no damage...add more layers...its supposed to take up the difference.

If someone has a better method...try theirs if its more safe...you could cut some small maple/oak hardwood horseshoe shapes and do the same thing in place of the foil layers