Can you clean rusty brake rotors?

Cleaning rusty brake rotors is possible in some cases, but often replacement is the best option. Rust on brake rotors can cause vibration, noise, reduced braking power, and rotor damage. Mild surface rust may be removable, but rust that penetrates deep into the rotor requires replacement. This article examines options for cleaning or resurfacing rusty brake rotors and when replacement is necessary.

What causes brake rotors to rust?

Brake rotors are made of iron, so they naturally rust when exposed to moisture. The following factors can cause brake rotors to rust:

• Road salts, brine solutions, and winter road treatments
• Rain, snow, puddles
• Condensation when vehicle sits
• Corrosive brake dust
• Wheel acid and other caustic wheel cleaners

Rust typically appears first around the outer edge of the brake rotor surface. Over time, it can spread across the contact surface where the brake pads press against the rotor. Rust may also form underneath the rotor surface.

Can you resurface rusty brake rotors?

Resurfacing a brake rotor means machining off a thin layer of the rotor surface to restore a smooth, uniform finish for the brake pads to press against. This requires a brake lathe tool. Resurfacing is an option if the rust is mild and limited to the rotor surface. The machinist will check that the rotor meets minimum thickness standards after resurfacing.

Thick rust buildup and deep pitting into the iron means the rotors are too far gone to resurface. Machining too much material off will make the rotors too thin and unsafe to use. In that case, replacement is required.

Methods for cleaning rusty brake rotors

Here are some methods that may successfully remove mild surface rust from brake rotors:

• Sanding – Using 220 grit or higher sandpaper, wet sanding can smooth and clean the rotor surface. Avoid grinding into grooves. The rotor must retain a uniform thickness and smooth surface for proper brake function.
• Vinegar – Spraying or rubbing full-strength white vinegar on rust spots helps dissolve rust. Rinse thoroughly. Vinegar may etch the surface, so sanding and polishing after may be needed.
• Naval jelly – This phosphoric acid-based metal cleaner helps dissolve rust. Rinse thoroughly afterward.
• Wire brush – Gently brushing with a brass wire brush can remove loose rust flakes. Avoid digging into the iron.
• Rust converters – Special rust converter chemicals change rust into an inert material that seals the surface.
• Baking soda and water paste – Make a paste with 3 parts baking soda to 1 part water. Scrub onto rust spots using a soft brush or pad. Rinse thoroughly.
• Brake cleaner spray – Non-chlorinated brake cleaner can dissolve rust buildup. Avoid oil-based formulas. Rinse afterward.

Always test cleaners in inconspicuous spots first to avoid damage. Thoroughly rinse rotors after cleaning. Wiping down with brake cleaner removes any residues. Allow rotors to fully dry before reinstalling wheels.

When to replace rusty brake rotors

If rust cannot be fully removed with cleaning methods, replacement is required. Here are some signs that brake rotors are too far gone:

• Deep rust pitting, holes, cracking or gouges
• Thick rust that cannot be sanded down
• Warping or irregular thickness
• Severely reduced braking performance
• High-pitched squealing on application
• Excessive vibration at high speeds

Machining rusty rotors too thin can cause them to crack from heat stress. Rotors must meet OEM thickness specifications. Check measurements against manufacturer service limits before resurfacing.

Replacement rotors should always be installed in axle sets to retain equal braking on both sides. Mixing old and new rotors reduces effectiveness.

Tips for preventing brake rotor rust

To minimize rotor rust, follow these tips:

• Wash wheels often to prevent corrosive brake dust buildup
• After washing, spin wheels to dry rotors fully
• Park vehicles in dry garages when possible
• Avoid wheel acid cleaners which promote rust
• Lubricate caliper pins and slides
• Replace cracked brake hoses that allow moisture in
• Check parking brake isn’t sticking and causing rust spots
• Apply high-temp brake lubricant to pad contact points
• Consider occasional resurfacing to remove minor rust

Rust prevention spray products can also protect rotors between uses. Fully curing the coatings before driving is important.

Brake rotor rust – Key takeaways

Here are some key summary points on dealing with rusty brake rotors:

• Mild surface rust may be removed, deep rust requires replacement
• Resurfacing is an option if rotors meet minimum thickness
• Cleaning methods include sanding, naval jelly, vinegar, wire brushing
• Signs for replacement: deep pits, cracks, warping, reduced braking
• Always replace axle sets, not single rotors
• Prevent rust by regular washing, lubrication, protectants

Frequently asked questions

Is it safe to drive with rusty brake rotors?

Mild surface rust may be safe for short trips to the repair shop. Any deep rust causing vibration, noise or braking issues means rotors should be resurfaced or replaced before further driving.

Can I use sandpaper to remove rust from rotors?

Yes, using 220 grit or finer sandpaper can smooth and clean rotor surfaces satisfactorily. Take care to sand evenly and avoid digging into grooves. The rotors must retain a uniform thickness for safe operation.

What happens if I put new pads on rusty rotors?

Rust prevents pads from properly bedding into the rotor surface. Pads will wear rapidly trying to smooth the uneven surface. Rust flakes can break off and damage pads. Performance will be poor unless rotors are refinished or replaced.

How much does it cost to resurface brake rotors?

Typical resurfacing costs $15-30 per rotor. Replacement rotors cost $25-100 each but avoid labor time. Compare costs to your specific vehicle and repair quote.

Can I use Coke to remove rust from brake rotors?

Soaking brake rotors in Coca-Cola can help dissolve mild rust. The acidity and carbonation assist the cleaning process. Thoroughly rinse rotors after soaking to prevent sticking and residue.

Comparison table of rotor rust solutions

Solution	Cost	Effectiveness	Caveats
Wire brush	Cheap	Removes loose rust only	Doesn’t stop ongoing rust
Naval jelly	Cheap	Good rust removal	Must thoroughly rinse after
Vinegar	Very cheap	Mild rust removal	May slightly etch rotors
Sanding	Cheap	Good surface smoothing	Labor intensive
Resurfacing	Moderate	Excellent refinishing	Needs machines and skills
Replacement	Expensive	Fully restores function	Major expense for labor and parts

This table summarizes popular solutions for dealing with rusty brake rotors and their relative cost, effectiveness and caveats. Factors like labor costs and part prices for specific vehicle makes and models should be considered when deciding between rotor refinishing or replacement.

Conclusion

Mild brake rotor rust can often be removed through cleaning methods like sanding, naval jelly or vinegar. Deeper rust penetration requires rotor replacement. Resurfacing rotors is an option if adequate thickness remains. New pads should never be installed without addressing rotor condition first. Regular washing, lubrication and preventive steps will minimize rust formation. Compare costs and benefits to determine if refinishing or replacement makes better economic sense for your vehicle.