89 pontiac formula 350. The fender walls where the strut mount is braced to that area on both sides under hood is all rusty,... how do i go about replacing those? i have added a pic and were the red line circle is the metal i need to raplce any ideas?

That's a bad place to have rust. Don't replace it if you just think it looks bad, only replace it if you think it effects the vehicles integrity.
If you do replace it, you'll need a donor vehicle to take the parts from, as you can no longer get replacement pieces for there.
You could just use this as an excuse to build a tube front end, that will be stronger and weigh less.

In the pic, the areas don't appear to be terribly bad. If the rust is minor, I'd suggest a dab of POR-15 here and there.

JamesC

If the car was here i would take pics to better describe, the problem here. Lets just say that this is cancerous problem. Its not something i can just paint over. I have done that, bout a year thinkin it was that bad, but now that my finger will easily go through some parts i am considering either gettin rid of the car, or fixing it if anyone is interested offer

Not a good place for rust... My uncle had an olds 88 i patched that darn thing twice on each side.... Id suggest droping the suspension if u can, tarp the motor and master cylinder.... soda blast the hell out of it... if theres small areas that push through and its not directly over the mounts weld in some patches.... then as said before por 15 everything!.... Goodluck keep us up to date... i personally have not had luck patching that area but i did not por 15 after the patches i merely painted. and i did not take anywhere near the time i would if it was on my iroc.

what do you por 15? i have no clue what your talkin bout i am gonna be yanking the engine here soon anyways to put new top half on motor so i was thinking of droping suspensiob then cleaning it all up and stripping the engine bay cutting them out and replacing them?

That would work. What if you just cut out the rust and had a good welder weld in replacement panels. A good welder could do it.

Kevin

por 15 is paint thats used to deter rust from forming. Go to por 15.com helps stop rust from coming back after u get the area fixed.

to remove it yeah gotta cut alot of spot welds

If the top "cap" piece where the strut bolts into is the issue,
that might be managable. If the issue is in other layers of the
fender well, PITA is inadequate, since the sub-frame support
is integrated into this structure.

Solving the "cap" issue might be accomplished by cutting a
larger portion out of a junk-yard donor. Then you can
identify/cut all the spot welds to determine if you want
to continue that process on your vehicle. And give some
thought about what will be necessary to get the replacement
piece properly aligned before re-welding.

Good luck