[reddogracing]

Any ideas on treating rust inside rockers? This is an old Impala, some rust through at the front and rear, and rust on the interior surfaces. The rockers are a three piece sandwich. Any ideas for stopping it, maybe something like POR-15? Thanks.

 

[001mustang]

Some "rust treatments" can make it worse by trapping water.
If you dont want to weld in new metal I would make sure water has a place to drain. You may need to drill some strategic holes to allow water to drain.
If you can remove rust to shiny metal then some undercoatings work well.
If you can't clean it properly then keep it coated with WD-40 or with a non-hardening rust treatment liquid.