Rear quarter extension

Hi! Just joined this forum just finished painting my 67 xr7 and I’m stumped on how the rear quarter extensions are supposed to be installed as far as the studs and seal. The seal that I purchased seem too wide, do they need to be trimmed? And why the 2 nuts per Stud? Thanks in advance

The seals are usually molded in pairs so you have to split the pair and then cut them to length. There should be three studs per extension so 12 studs and 12 nuts.

And the reason there are two nuts per stud is so you can set the spacing of the extensions away from the body in such a way that you don’t pull them in too far. I believe mine had a flange type nut also that had like a caulk type material that sealed the nut to the body hole.

Ok perfect thank you for all the info.Wished I hadn’t removed the studs.

The seals are a issue these days due to “shrinkage”!
Here are the pieces I have left over the years.


The one on left is near original size.Middle was offered for years, but was smaller in size.
The latest Dual attached type you split is the smallest on right.

So, this causes the extension NOT to seal to the body…
How to solve this?


Using the seal, dont install like original, one half in slot, you can stuff both sides in slot!

The extensions have a tab on each post that holds it away from the body. Factory did use a washer also, AMK offers the nuts w/ mastic sealer attacked for tail lights, gas door & extensions