Holes too large in firewall to mount voltage regulator etc.

[mseagle]

I need some help guys.  The Challenger just got back home from the body shop after a year long restoration.  I ordered the correct OE restoration paint cutter bolts to hold the voltage regulator, starter relay, etc to the firewall and fender.  The holes are too large from someone a long time ago using a different bolt to mount the items.  The new bolts will just not bite.  Short of going to the hardware store and trying every possible larger bolt, does anyone have any tricks to fix this?  I would really like to use the OE style bolts but the car is all painted and nearly plumbed out.  Welding the holes in is not an option.

Any help is greatly appreciated !!

Thanks,

Mark

[1 Wild R/T]

The OE bolts for the regulator & ballast have a smaller head & a built in washer but the thread is standard 1/4-20 so you can put a nut on the back side in the cowl vent area....

[manycj]

You should be able to use nuts on the back side (inside the cowl).

[mseagle]

Hey didn't even think of that.  Thanks a lot! 

[Shane Kelley]

Very common problem. I like using the 1/4x20 serrated flange nuts on those. (see pic) They lock to the body pretty good so you don't have to keep holding them with a wrench while tightening the bolts. Also acts like a lock nut and won't loosen up on you. 

[mseagle]

Thanks, I will be picking up some today. 

[Spikedog08]

Yep . . . what they said.  I have to do the same on the convertible . . . 

[anlauto]

When I run into that issue.....my first thought...."Ahhhh nuts"....

[Cudakiller70]

Would nutserts be an option?

[1 Wild R/T]

Would nutserts be an option?

Yeah, but it wouldn't look stock... The nuts are invisible & work great...

[GoodysGotaCuda]

Be sure you make good contact with bare metal so that it grounds and can actually regulate voltage...


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[anlauto]

Would nutserts be an option?

Yeah, but it wouldn't look stock... The nuts are invisible & work great...

....and you can get them super tight for a good ground and not worry about stripping them out like nutserts

[GoodysGotaCuda]

Would nutserts be an option?

Yeah, but it wouldn't look stock... The nuts are invisible & work great...

....and you can get them super tight for a good ground and not worry about stripping them out like nutserts

Properly installed nutserts are very strong. They hold in my radiator, ebrake cables, HVAC box, etc. All of the body ground on my car are se with dielectric grease and a nutsert as well. No problem.

[jimynick]

Unless the previous owner drilled the holes oversize and if you're able to access them, you should be able to take two small hammers and using one as a buck, use the other over the hole to gently peen them further closed from the back side to allow the bolt to bite. If you're careful and accurate you should be able to do this without leaving visible marks. Just my 

[RUNCHARGER]

In a low stress situation like that you can also take small pieces of copper single strand wire (say 1/2" long) and bend them into a u-shape. You can clip them in the bolt holes two per hole and they will allow the bolt to be tightened up into the too large hole.