Is there a way to prevent cab corner rust?

[deckeda]

My ‘89 has low miles and has likely not seen much salt. No rust as far as I’m aware. Other than it being a ****** design that rusts, I haven’t yet read WHY these trucks rust there.

There’s also both a ‘93 and a ‘94 in the family, both with either cab corner rust or rust under the extended cab section of one ... but they’ve also only been driven in the same areas.

 

[TechNova]

Lots of cavity wax https://www.johnsonautobodysupply.com/3M-Cavity-Wax-Plus-08852.html
get the applicator set for it also. flood a bunch in the hidden areas until it is dripping out. Most places you have to do it by feel.
For doors and fenders a little disassembly will get you a better view to see coverage.
You can also us WK SealOut but it needs a applicator gun.
I have used SealOut for 30 years, it will flow a little and then stay in place, stays soft, doesn't dry out.

The 3M works good but it is thinner I think I would reapply it every 3-5 years. I have not used it long enough to know if it stays longer.
It is easy to use in the aerosol.

For exposed areas you need a quality undercoating.

 

[deckeda]

Thanks! I'll give it s try. Now, for the actual cab corners (which seems to be where rust is worst?), do you remove the inner panels to get to them from the inside, or can crevices be accessed from under the truck? I'll take a look under there.

 

[MIHELA]

On the extended cabs you can get at a lot of the backside by taking out the garbage cans next to the seat. Minimal effort needed.

 

[jdla140]

There are little plastic plugs on the back side of the rockers that will allow you to spray cavity wax/oil/metal protector whatever you prefer in. I do it before every winter