Fender bolt size?

[76on44s]

I need help trying to figure out what size the inner and outer fender bolts and u-nuts are on my 76 k10 pickup.Also where is the best place to order them from? lmc is a bit high

[paintslinga2010]

Im in the same boat. I am using the original bolts though. The only thing I can get to come close to fitting are m8 u nuts from oreillys. Going to try them tonight.

[ray_mcavoy]

The factory thread size is 5/16" - 18.

Most auto parts stores carry replacement U-nuts and body bolts. I have a CarQuest autobody hardware catalog that lists the following part numbers:

8131239 = 5/16"-18 U-nuts
8151207 = 5/16"-18 body bolts (7/8" long)
8151279 = 5/16"-18 body bolts (1" long)

These body bolts are the OE type ones with a captive washer and pointed end.

Some of the fender locations (like where they attach to the cab) use larger 3/8"-16 bolts. Part numbers for those are:

8151315 = 3/8"-16 body bolt (1" long)
8151333 = 3/8"-16 body bolt (1-1/2" long)

I think all the nuts for the 3/8" bolts are welded to the cab, but if you need any 3/8 U-nuts, the CarQuest number for those is #8132240.

[76on44s]

Thnaks Ray. Thats good info!