Subframe Corrosion Repair Cost

Subframes make up a significant amount of a car's structural integrity, being the thing that ties the suspension to the body shell. However, like any underbody component, they are subject to extremely harsh conditions, especially in the UK, with our damp, salted roads.

This article explores the costs involved with repairing a corroded subframe and what to look out for when having the work done.

What is a car subframe?

Almost all modern cars have both a front and rear subframe; these provide stiffness and strength for the suspension components to mount to the bodyshell. The front subframe typically also supports the engine, gearbox and drivetrain components.

Car subframes are almost always made from steel, which is a strong and cheap material to use. It does, however, rust readily if not sufficiently protected.

Subframe corrosion repair cost

The cost to repair a corroded subframe can range from £300 to £3,000, depending on how bad the corrosion is, and how complex the car is.

Minimal rust can often be wire-brushed and treated, which could cost as little as £300 and be done in an afternoon, but if your subframe is very rusty and needs replacing, expect to pay a much larger bill.

Factors that affect subframe repair cost include:

Which subframe needs repair - the front is typically more work to remove, as it holds the engine
How rusty the subframe is - if the damage is only surface corrosion, it may be possible to clean and treat the surface instead of removing the subframe completely
Availability of parts - If parts are difficult to obtain, the cost may be higher than other models

Why do subframes rust?

Cars are mainly made of steel, a metal very susceptible to corrosion in the right circumstances. Water causes the iron in the metal to turn into iron oxide, AKA rust. Thanks to our decidedly wet weather in the UK, cars here are more susceptible to rust than most.

Another contributing factor is salt, which accelerates the corrosion process, and with tons of it being spread on UK roads every winter, poorly protected cars don't stand a chance!

How to prevent subframe corrosion

If you cannot avoid driving on UK roads throughout the winter, there are some things you can do to protect your car's subframe and entire underbody from rust:

Have it undersealed or protected
Jet wash road salt and mud off periodically
Keep the car in a temperature-controlled garage

The best way to protect your car from corrosion is to avoid driving in the winter, but this is obviously not feasible for most people, the next best option is to apply a protective coating to the subframes, suspension components and underbody.

Products such as Lanoguard and underbody sealant can help protect the metal, but be sure to apply them only when the metal is free from rust; otherwise, any existing rust will continue to spread under the coating.

Mud and salt can also stick to the underside of your car, especially if the roads are particularly dirty. Pressure washing the suspension, wheel arches and underbody may be a bit extreme for most, but it can help to prevent corrosion in the long term.

How to check if a car's subframe is rusty

Take a look under the car at both the front and rear. The subframe should be easy to spot; look for where the suspension arms are attached to, it will be a different colour to the bodyshell.

If you’re looking at a car for sale, or simply want to check your own car, it can pay to see if the subframe is rusty, look for obvious signs of rust, large amounts of orange, or powdery rust is cause for concern.

Get your subframe repaired

If you need a subframe or any suspension work, Bumper's car repair finance is a great way to spread the cost, interest-free. Select from a large list of approved garages and ease your cash flow.

Author - Joseph Law

Joseph has been writing about cars for over eight years and writing for Bumper for over three, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.