This is the first time I am undercoating all of my veichles, about 15 of them, most of them are 3/4 and 1 ton pickups, they range from 15 years old to brand new. Most have rust on fenders and some cab corners. Do I just put on 1 coat in fall? Or maybe a coat mid way for winter? Do I do one in spring or just once a year in fall? Will keep these trucks along time. When I read online it sounds like If they are rusty maybe i should do a second coat as rust sucks it up. ? I am planning to not do any washing under until winter is over. Any practical advice would be appreciated

I spray my truck late august each year when its gonna be a real hot day. The hot weather allows it to creep better. The areas that might need touch up more frequently are the areas that get direct road spray...thingk front side of rear axle and diff and areas immediately behind tires. Most other areas are still looking good the following August. I also suggest getting the black fluid film...reallly aids in seeing your coverage when you are applying it. I did not start with a rusty truck though, so cant help you with whether or not it takes a second coat. I will say this....it sure wouldn't hurt anything. With that many vehicles to do, I hope you are buying by the gallon and using a gun to spray it

My mechanic power washes my two trucks on the lift then the next morning, first thing sprays them and puts them outside for me to pick up......jk

I wish I had someone here to do that! That's a heck of deal, unless he charges an arm and a leg...

Sounds like you closed the gate...after the cows got out
...

As far as the trucks that don't have any rust...pull the rocker plugs..

Squirt fluid film in there...drop the spare tire too...spray every where.

Pay special attention to the cab mounts...blow the dirt out...before fluid film

Do mine in October...then June.

For the frame ..I prefer Wool Wax.

It's another aerosol can spray....that hangs on the frame better.

But fluid film for the rest

What is something like that cost for fluid? Do body shops do this type of work.

Your bang for your buck is to start rust proofing when they are new before they ever see salt. You need to remove fender liners and spray above them. You need to spray inside any hole you can find to get the fluid inside the panels.

Do it annually and like has been said, power wash everything before the next application.

Don’t forget to drop the spare tire and spray above that. Apply plenty to both sides of the spare tire before you put it back too…it collects all kinds of salt under there!

Any plugs u find take them out and spray in. Doors, rockers cab corners. Pull door panels off and spray in. The more u can do the better.

Yep

I purchased 5 gallon pails and a sprayer. Definitely wish I would of started this years ago, but better late than never