What do you spray under trucks driven on salty roads??

Normally it is something like Zebart Rust proofing, at least in Buffalo, NY that is what you would find dealer sprayed. Just about any undercoating material would work too, however if you have the means to, I would recommend that you have the undercarriage power washed and then sprayed with a bed liner like Linex or what ever you have available.

And How would u get the bolts out to change a part in the underbody ?

The same way you do now. I did not say it had to be sprayed on as thick as a bed liner, only to use a bed liner spray, but hey I was only born and rasied in Buffalo and I only have bed liner spray on the under side of my truck, so I don't know.

Add to that, at least I provided the OP some useful information based off experience and knowledge, too bad we can't say the same for some. :)

I will tell you what I have been doing for many many years. I save my old gear oil and I spray the bottom of the truck every fall and in the spring using it in a paint sprayer gun. It gets into all the cracks and joints a ns stops rust (gear oil has a anti rust additive.) and resists wash off. I spary into plases the Zebart cannot get too and it get nuts and bolts for fusing with rust. After a few years of this it kinda builds up a film covering that you build on every year with new coating. THis may sound extreme or far fetched but it does work very good. I have been doing this to my snow plow trucks for over 20 years as the salt they see can be extreme. I have seen Zebart fail because it can trap moisture under it and rust beneath it and then flake off. Also the spraying lets you coat brake lines and fuel lines and such which Zebart protects poorly and are sometimes the first thing to go to rust. The only draw back is that it can smell for a few day afterwards sometimes but I do it to my trucks and plows and that are basically rust free and bolts are not rusted. I have seen plows that look worse than mine after 2 or 3 years and my oldest plow in 12 now and still in fine shape and frame for it is still rust free. Yes it is a bit of a hassle but I can work on them and they are not rusted solid either and even bolts under truck come off well too.

----------------- TheSnoMan.com

What does it do to the rubber parts?

Al

Not a thing that I have observered in many years of usage. The heavier the grade the better and I usually use used 85w140 that my tractor uses 3.5 gallons of when I change it or some used 80w90 mixed with it. I keep it in a 5 gallon bucket and add to it when it is low. By setting in the bucket for extended periods all the sediment settles out of it and the oil you pour off to spray is pretty clean. You want oil pretty warm to the touch if spraying in cold weather. I use a fan nozzle that I can rotate 90 degrees so I can spray a vertical of horizonal "fan" when I put it on. It really works pretty darn good and EP gear oil attacks rust far more agressively than motor oil.

----------------- TheSnoMan.com

Thanks for the information... I just bought a truck off of EBAY from Minnoseta. I did a carfax and that is were it came from. I'm here in Tennessee.... This truck is a 2000 Chevy.. It now has 7 years of salt roads...

Spray it down good and soon and again in a a few weeks to make sure you stop rust present on it now.

----------------- TheSnoMan.com

I use a pump up sprayer to do this? I'm flying to Minn on Thur and have a

rhino liner or hurculiner or anything to that effect will work to prevent any rust or corrosion on the main frame of the truck and it will also protect it from major cuts or bangs for the more off-road orrented person.