I just bought a 70 Malibu and overall there is not much rust. But it had a vinyl top that was removed and has been leaking around the back window in each corner. This has caused what seems like minor to moderate surface rust down the inside of the right quarter and various other spots in the trunk. Also there was a small patch of "bondo" work done on each of the lower quarters.

My question is after wire brushing the loose rust off and "cleaning up" would applying POR-15 directly over the rust stop it from progressing further? I'd like to stop it from rusting from the inside-out.

Also there are a few other spots of rust:
- Small spot on the bottom of the passenger side floor pan.
- Inside of the front fenders.
- Very bottom (underside) of the quarterpanel.

Would POR-15 be appropriate to apply in these areas also? I would think that applying POR-15 to the inside of all metal, non-visible areas of the car would be a good idea as a rust preventer. I am planning on removing both fenders to get an idea of the shape they are in and was thinking about applying POR-15 to the entire inside of the fenders. Are there any drawbacks to doing this.

My main goal is to stop existing rust and prevent any new rust wherever I can. Any tips or advice would be greatly appreciated.......Thanks!

I have never used POR15. I have used "OSPHO" and it turns all rust into a hard black substance that you can paint over. It is basically phosphoric acid. It cheically changes the rust and nutralizes it. I get it at Home Depot for less than $10. If the POR15 is better for any reason I'd also like to know. The OSPHO seems to work just fine for me.

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need to get the wife to work to buy more chevelle parts.