Fix screw holes in wheel center cap ?

[Racer57]

I have one hole thats completely stripped out and several others that are close. Is it possible to fix them ?

[Katfish]

What about epoxying in a stud?

[Floyd]

I filled the holes with JB Weld and then drilled and tapped.  I'll dig up some pics and post tomorrow

[Floyd]

I thought I saved some pics but can't locate them.  Anyway, JB Weld repair process was pretty straight forward.  I mixed up a batch and filled the holes using a toothpick to work it into the cavity and ensure there weren't any air bubbles.  Let it cure thoroughly and then drilled it out with a #7 bit followed with a 1/4-20 Tap.  I'm confident they'll hold, especially if you have some with good original threads.  A friend pointed out that Mopar went from 5 screws to 3 screws for Rallye wheels centers beginning in 1972.  I don't think much torque is required to get a secure fit.

[Racer57]

I thought I saved some pics but can't locate them.  Anyway, JB Weld repair process was pretty straight forward.  I mixed up a batch and filled the holes using a toothpick to work it into the cavity and ensure there weren't any air bubbles.  Let it cure thoroughly and then drilled it out with a #7 bit followed with a 1/4-20 Tap.  I'm confident they'll hold, especially if you have some with good original threads.  A friend pointed out that Mopar went from 5 screws to 3 screws for Rallye wheels centers beginning in 1972.  I don't think much torque is required to get a secure fit.

I have the holes filled with JB and waiting for them to cure. How did you hold the hub in place and keep from drilling too far ?

[Floyd]

I just drilled them by hand and marked the desired depth on the drill bit prior to drilling. 

[mtull]

I've used:
- magic marker line at the desired stop depth
- layers of tape wrapped around the drill bit at the desired stop depth
- adjustable drill depth stop collars at the desired stop depth

However I've never tried to drill into JB Weld so I have no idea what it's like.  I can say from experience with some types of wood it seems that very very teeny tiny extra bit of pushing effort that you think wouldn't make any difference results in a sudden 1/2" of forward progress when you only wanted a 1/4" total depth.   

[Floyd]

JB Weld is fairly soft if I recall correctly.  It really was pretty straightforward however, I don't remember having any difficulty getting the right depth.  Good luck

[Brads70]

I've used:
- magic marker line at the desired stop depth
- layers of tape wrapped around the drill bit at the desired stop depth
- adjustable drill depth stop collars at the desired stop depth

However I've never tried to drill into JB Weld so I have no idea what it's like.  I can say from experience with some types of wood it seems that very very teeny tiny extra bit of pushing effort that you think wouldn't make any difference results in a sudden 1/2" of forward progress when you only wanted a 1/4" total depth.   

in addition, a section of rubber hose to act as a stop...

[70_440-6Cuda]

I filled the holes with JB Weld and then drilled and tapped.  I'll dig up some pics and post tomorrow

JB was going to be my suggestion as well.  I will often drill a small pilot hole when worried about the depth to avoid what @Brads70  referred to with the sudden "grab" and over drilling that I have also experiences, mostly with wood or plastic also

[mtull]

While were on the topic of center cap screw holes, is it best practice to tap the holes if the center cap has never been used or do they come already tapped?

[Racer57]

Used JB Weld. Used some small pieces of wood to hold the cap up so I could square it with drill press. Wrapped tape around drill bit. Drilled and tapped real easy. I panicked for nothing !   

[7E-Bodies]

I had all of my originals restored by an amazing local powder coater that matched texture as well as color (color was matched to a single NOS one that I was lucky enough to acquire). When I got them back, I was shocked to find about half of the holes were stripped from 50 years of, well, 50 years. I ordered a helicoil set, complete with tool to install them ($20 ish as I remember, on Amazon). The set I got was for a 5/16" hole tapped at 5/16 18. I very cautiously drilled out all 20 holes, tapped to the 5/16 18 that came with the set, then installed the helicoils and was amazed. Zero regrets.

[7E-Bodies]

Here's a few photos I forgot to add. IMHO this is the ONLY way to fix these correctly and safely.

[7E-Bodies]

@mtull the ONE NOS center cap I was able to obtain had zero threads. I am under the belief that the factory bolt was machined in such a way as to cut it's own threads. That when combined with the less than desired pot metal (my term), these threads were made to fail. I am absolutely certain I did the right thing by drilling out the old threads slightly and inserting 1/4" helicoils into a freshly tapped 5/16 thread. The coils lock down incredibly.