Also here's something I found on my '41 truck about the F-100 brake conversion. "I did also want to post about the F100 conversion just in case everyone didn't know. There are 2 wheel seals for this conversion and everything I read only talked about 1. You need to measure the seal hub on the spindle, 1 1/2" is the National 450461 (in all the articles), if it's 1 9/16" then you need a National 473441. If you have the wrong seal it won't go on the last 1/4" or so, you can force it but it drags bad and will most likely waste your seal."