How to replace or restore studs for heat shields, wheel arches, etc

[FireFox31]

What's a good way to replace or restore the studs on the underside of the car which hold on heat shields, wheel arches, etc? The center muffler heat shield on my 2000 V70 broke and the studs to attach it look weak from rust so I want to rehabilitate them. Thanks for your input.

I could cut off the studs, grind away the rust, and use JB Weld or actually weld stainless bolts in their place. I could finish it by spraying the area with anti-rust paint to protect the bare metal on the body which I exposed.

Alternatively, I could use a die to cut new threads on the studs. They're so rusty that I don't think they'll survive.

I don't want to drill self-tapping screws up into the metal from below or down from above. That would make a breach in the body which could allow in water, leading to corrosion. I guess I could put silicon at the base, but it still seems bad.

[Sveedy]

Ok well looking at what your dealing with, worrying about corrosion seems to be futile. It's already there.
I think I'd resort to pop rivets in your situation. Probably be the least " invasive " and pretty quick and easy to do.
No sealant will ever stick to what your dealing with, so don't waste time with that. Probably end up just trapping more water anyway.
If one was truly anal, a rubber washer/s of some sort could be used in conjunction with the rivet.

[scot850]

Replacing these will be a challenge. If your welding is good then removing the old ones and replacing with stainless would be the way to go. I also epoxied large stainless steel washers on to the heat shields to return some integrity to the mounting holes.

Another option is to try and find some of those washers that hold interior parts in place that have teeth on them that bite into the metal as you push them on but lock in place once on there. I would still use stainless washers glued to the heatshield.

I would agree that treating and protecting the area under the shield would be a good idea for longevity, but that would mean you could also epoxy the shield permanently in place and not worry about it using the original studs.

Neil.

[abscate]

Maybe just some copper wire around those nasty studs to hold the shield in place, or if you can find some slightly smaller plastic nuts, those will hold on those studs, too

[850oldschool]

rivstuds (bottom of page):

https://www.boellhoff.com/us-en/product ... rivnut.php

Pinch weld primer or another moisture cured urethane such as SEM rust trap is good for small bare metal situations:

https://www.semproducts.com/product/rust-traptm/traptm

Aerosol Rustoleum Rust Reformer plus Cosmoline RP-342 for undercar surface rust: