Avoid gravely areas, uneven fields, or areas near heavy traffic.
Consult your vehicle’s owner’s manual for the best jack placement. Keep your jack stands nearby while you lift the car so you can quickly place them. If you’re de-rusting a truck, it may already be high enough off the ground without jacks. Otherwise, dealing with rust under a truck is the same as under a car.
Soda blasting or sandblasting the surface rust can also be good options for optimal removal. Wear goggles to prevent rust flakes from flying into your eyes. For maximum safety, keep them on for the rest of the rust treatment process, too. It’s OK if you don’t get 100% of the rust off manually. You’ll be adding liquid removal agents after this step. If there is deep rust (rust that has weakened the metal or caused holes to form), take your car to an auto shop for professional treatment or to get a replacement part. It’s not possible to remove this kind of problem at home.
If needed, remove the wheels to easily access the wheel arches for cleaning.
The degreaser removes any last oil, wax, rust flakes, or debris from the undercarriage to help primers and rust reformers stick. Purchase an auto degreaser from an auto shop, hardware store, or online.
Wait until the undercarriage is completely dry before doing any more cleaning or applying anti-rust treatments. Place fans underneath your car to speed up the drying process.
You’ll probably need multiple coats to thoroughly coat everything. Read the primer instructions to know how long to wait between coats. Primer helps your rust reformer stick to the metal under your car. Rust converter primers are available online or at most hardware or auto shops.
Oil-based sprays work their way into small crevices easier than thicker sprays. Rust reformers are available online or at most home improvement, hardware, or auto stores.
This step isn’t required, but it can add another layer of protection.
Your car is most vulnerable to rust in the spring because of the moisture in the air and the fluctuating temperatures. Aim to wash your car every 10 to 20 days during winter if you can. Drive as little as possible before, during, and after winter storms when there’s extra salt on the roads. [10] X Research source
Steer clear of puddles. They contain salt and debris that wreak havoc on your undercarriage. Wash your car after excessive puddle exposure. [12] X Research source
If it’s difficult to examine your undercarriage because your car sits low, lift it with jacks or ask your mechanic to take a look next time it’s in the shop.
