We Buy All Cars, Running or Not!

Complete Guide on How to Fix Major Rust on a Car

Guide on How to Fix Major Rust on a Car

Rust on any metal structures is never good news, especially when it comes to cars. Not only is it unsightly but it’s also a silent killer of vehicles. If you ignore the first signs of rusts it will spread over time and eventually wear out not just the body of your car but its parts too and that spells disaster. But if you are committed enough there are things you could do, and in this article we will discuss how to fix major rust on a car.

Auto Repairs Are EXPENSIVE

How to Fix Major Rust on a Car: Is fixing rust on a car worth it?

Before learning how to fix major rust on a car, it’s better to know is fixing rust on a car worth the trouble? The answer is it depends on the location of the rust and how extensive the rust is. If it’s only a superficial rust or a small amount of surface rust and you are able to catch it early then it’s definitely worth fixing. You could still fix the rust and enjoy your car for years to come. A rusty frame, however, means your car is best headed to the junkyard.


To decide better here are the things you will have to consider: 

  • The age, the mileage and the value of your car


Age, mileage, and price. Think about these factors and weigh in if it’s worth the trouble of going through all the steps on how to fix major rust on a car when the car is so old with so many miles on it. It might just be time for your car to retire.

  • Rust Type 


Surface, scale, and penetrating rust are the three forms of rust. Understanding these types of rust will guide you as you go through the steps on how to fix major rust on a car.


Surface rust is just like how it is called — rust on the surface. If you leave a car with steel disc brake rotors parked for a while, surface rust will build on the rotors. That's never a problem, though, because the rust is usually cleaned off the rotor after a few turns. Surface rust can be easily and cheaply repaired. 


It can be more difficult to fix a scale rust, which exposes the raw metal behind the paint. If you don't treat surface rust and allow the decomposition to move further into the metal, you may notice bubbles forming in your car's paint. This happens because iron oxide molecules are physically larger than iron or steel molecules. 

The rust problem worsens by expanding and peeling away the outer layers of paint and metal, exposing new base metal, which subsequently corrodes. When rust penetrates the surface in this way, it forms scale, which is a rough, pitted type of damage.


A penetrating rust however, already managed to convert the car's steel to iron oxide, making it brittle and causing holes to emerge. This is a lot more difficult to fix. If untreated, rust will eventually eat through your car's metal. Penetrating rust causes everything from Swiss cheese-style holes in the fenders to more hazardous issues with weakening frames and suspension components.

  • Where the rust is located


Corroded exhaust or fuel tank supports are obvious hazards. Rust on the underframe might impair your ability to drive safely, and rusted body panels can put you and your passengers in danger in the event of an accident. Rust that penetrates these areas can allow water (which is detrimental for the car) or exhaust to enter (very, very bad for your health and for anyone riding your car). It's possible that repairing these rust issues isn't worth it.

How to Fix Major Rust on a Car: A Guide


It's easier to prevent rust than to remove it so at the first signs of rust it’s best to do something about it but remember that if you have failed to catch it early there are some things that you may still be able to do. But take note that some rusted regions may be more difficult to repair than others, and this is mostly dependent on the degree of rust. Because rust is caused by the oxidation of the metal itself, heavily corroded metal can't always be cleaned and may need to be replaced.


Fortunately, if the rust on your car is the consequence of an accident or a poor repair job, then comprehensive car insurance policies may cover its repairs since it isn’t caused by natural wear and tear. Contact your insurance carrier immediately once you discover the rust. Rust caused by improper care or normal wear-and-tear however is not covered so you will have to pay out of pocket for the service repair or do the fix yourself.


The fix may be mild and severe where you will have to learn how to fix major rust on a car. When it comes to severe rust, the rust has usually eaten all the way through the vehicle's sheet metal. You might be able to patch the hole in the sheet metal using body filler if it's little, but if it's huge, it's probably best to replace the complete rusty panel. Before you begin, think about your budget and the extent of the damage.


The repair needed may only be minor if the rust has not yet eaten through the metal. If this is the case, you'll have a lot less work to do. In general, the fix involves grinding away the rust, re-priming the exposed metal after mending any holes, and repainting the repaired area. 

  • Prepare the Tools You’ll Need


If you want to fix major rust spots, you’ll need specific tools that are necessary to get the job done. These include:


  • Mechanical sander or sanding block tool
  • Angle grinder
  • Putty or Body filler paste to fill in the dents or gaps
  • Touch-up paint (exact color of your car)
  • Standard car paint primer
  • Masking paper & tape
  • Safety equipment (gloves, safety goggles and a respirator or at least a surgical mask when performing rust removal)

  • Prepare Your Vehicle


Find a suitable location to do the repairs. An outdoor space or a garage where you don’t have to worry about other objects getting dirty as you sand away the paint and rust from the vehicle.


After having your car parked at the suitable location, prepare the vehicle by covering every inch of your car’s surface that has no rust. This will prevent you from accidentally sanding down any of the wax or good paint on your vehicle. Cover your car with a material such as newspaper, for instance. 


Simply secure the newspaper (or any other covering solution) to the surface of your car using the masking tape indicated above. Because sparks will be flying in the immediate area if you use an angle grinder to remove a substantial amount of rust, consider using a fire-resistant and durable protective covering for your car.

  • Sand down your car’s surface


It's time to start cleaning the rust now that you've properly prepared the vehicle. Sand down the paint and rust on the damaged surface with sandpaper. The goal is to keep sanding until you get to the bare steel. 


When sanding off the rust, make sure you are able to remove all of it before repainting. Otherwise, you'll merely slow down the corrosion process and see more rust surface all too soon. Use a sanding block to make it easier for you as you will be able to have better control. You can, however, perform it by hand if necessary. It's time to paint after sanding the surface down to the steel.

  • Prime and then repaint


You'll need to prime your car before you start repainting it. As this solution prepares the steel for a new paint coat, spray paint primer (ideally anti-rust primer) on the exposed steel surface. The initial layer, on the other hand, will not last. Sand down the first layer of primer as soon as it is applied. This procedure removes any rust particles that may have escaped the first treatment, leaving the steel as smooth as possible.


Prime the surface once more. Repeat the prime-sanding process until you're satisfied with the results if you want to be doubly sure you've removed all the corrosion. It's best to sand your last layer of primer with 400-grit sandpaper for the best results.

  • Paint and then sand down thick spots


You can begin painting the car after sanding and priming the exposed steel surface. Apply a small coat of paint to the first layer. Once it's completely dried, smooth it out with a piece of 400-grit sandpaper. You may have made a few thick patches in the paint layer by this time, but that's fine. You can whittle them down with a sanding block over time.


Repeat the painting and sanding process two more times. After applying the third coat of paint, wet another piece of 400-grit sandpaper and wipe it over the freshly painted area.

  • Lastly, put some clear coat


To keep the new paint from fading or tiny scratches, spray a clear coat over the area you have repainted. The fact that you'll be able to enjoy a glossy finish that will make your car look brand new is the cherry on top.

How to Fix Major Rust on a Car: How do I stop my car from rusting?


Wash, clean and wax your car on a regular basis. Washing and polishing your car not only improves its appearance but also protects it from rust. Every two weeks, wash your car thoroughly, including the underbody (or as often as once a week in winter, to clean off road salt). One of the most significant causes of rust is salt. The metal on your car will corrode faster if it is exposed to water. You will have to apply some coat of wax about twice to four times a year. Waxing before the first snowfall is especially crucial if you live in a snowy city.


Detect rust in its earliest stages. Check your wheel wells and bumpers whenever you rotate your tires, as these are great sites for rust to form. Using a yard hose, rinse the dirt away and inspect the area with a flashlight. Do you notice any rust spots? Have it taken care of as soon as possible.


Keep the interior of your car dry. When the interior of your car gets wet, the moisture is likely to transfer to the exterior. To avoid this, use a towel to thoroughly wipe out any moist surfaces inside your car. If you have any spills inside your vehicle, clean them up as quickly as possible. If you wait too long, the spill will become more difficult to clean. 

Keep an eye out for paint scratches. Your car's paint finish becomes subject to rust if it is scratched or otherwise damaged. Fortunately, there is a simple solution. A little scratch can easily be buffed away by an expert technician as long as it does not expose bare metal.


Take care of your vehicle. Treat your vehicle properly to avoid nicks and scratches that might lead to corrosion. Use a foam brush with soft bristles to remove snow the right way. Avoid putting your purse or briefcase on the car for more than a minute, and make sure your keys don't scrape the side.


Use a ceramic finish. While waxing your car used to be the most effective technique to prevent exterior damage, most auto shops now promote ceramic coating as a more durable and cost-effective option. The paint of the car can be treated using this liquid polymer. Even under extreme conditions, the ceramic coating adheres to the paint and will not break down. Waxing a car is required every few months, but with ceramic coating, you won't have to do so for up to three years.


Follow the steps on how to fix major rust on a car and the fix should last for the next years to come.You may need to do mild rust repairs every now and then which is completely normal. But remember to do it without delay. It’s always easier and cheaper to fix surface rust than rust that scaled or penetrated.

© 2022 Cash Cars Buyer. All Rights Reserved. Terms & Conditions | Privacy Policy | Sitemap