KBS does not recommend brake cleaner before painting. Brake cleaner and other solvent-based cleaners can leave an invisible residue that interferes with paint adhesion and flow out. Clean the surface with KBS Klean, a water-based cleaner and degreaser that leaves no residue, then rinse and let it dry before you paint. If you do use brake cleaner, wash the part with KBS Klean afterward to remove the residue.
Updated October 2026 by the KBS Coatings technical team.
- Can You Use Brake Cleaner Before Painting?
- Why Does Cleaner Residue Matter?
- The Water Test: Brake Cleaner, Lacquer Thinner and KBS Klean
- What Should You Clean a Surface With Before Painting?
- What You Need
- How to Clean a Surface with KBS Klean Before Painting
- KBS Klean Dilution Ratios
- Frequently Asked Questions
| Cleaner | KBS Klean, a water-based cleaner and degreaser |
|---|---|
| Pre-paint dilution | 5 parts hot water to 1 part KBS Klean |
| Aluminum, copper and brass | 25 parts hot water to 1 part KBS Klean |
| Wash time | 5 to 10 minutes for general cleaning |
| After washing | Rinse thoroughly with water and let the surface dry |
| Next step on bare metal | RustBlast, before painting |
Can You Use Brake Cleaner Before Painting?
KBS recommends against cleaning with brake cleaner before painting, because brake cleaner is a solvent-based cleaner and solvent-based cleaners can leave residue on the surface. KBS Klean is water-based, rinses off with water and leaves no residue. That does not mean brake cleaner can never touch the part. If you do use it, follow it with a KBS Klean wash and a water rinse to remove the residue before you paint.
We often get asked which cleaners are best on metal, plastic and masonry before applying paint or a coating. One customer contacted us about preparing and painting aluminum brake calipers with KBS Motor Coater. The caliper was relatively new and was not corroded, only covered in brake dust. He planned to wash it off with brake cleaner and go directly to paint. We let him know it would be much better to clean the surface with KBS Klean before coating.
Why Does Cleaner Residue Matter?
Cleaner residue matters because it creates surface tension in the paint or coating applied over it, and surface tension interferes with adhesion and flow out. Solvent cleaners, brake cleaners, solvent wipes, alcohol wipes and tack cloths all remove dirt, and all of them can leave residue behind.
Surface tension is the tendency of a liquid at rest to shrink into the smallest surface area possible. Water beading up on a freshly waxed car is the familiar example. Paint does the same thing over a contaminated surface instead of flowing out and bonding.
The Water Test: Brake Cleaner, Lacquer Thinner and KBS Klean
In a side by side water test, water beaded up on the panels wiped with brake cleaner and lacquer thinner and did not bead on the panel cleaned with KBS Klean. Beading water shows residue is still on the surface. All four panels started out contaminated.
- The panel on the far right is the control. It was not cleaned, and it was sprayed with water. The water beads up instead of flowing out because of the surface tension the contaminants cause.
- The two panels in the middle were cleaned with solvents, one with lacquer thinner and the other with brake cleaner. After the solvents were wiped dry, water was sprayed on. The remaining residue makes the water bead up.
- The panel on the left was cleaned with KBS Klean, then sprayed with water. The water does not bead, because the contaminants were removed and no residue was left to raise the surface tension.
What Should You Clean a Surface With Before Painting?
Clean a surface with KBS Klean before painting or coating. KBS Klean is a concentrated, water-based, non-flammable cleaner and degreaser that removes dirt, grime, oils, lubricants, grease, waxes, scum and other contaminants. It leaves a clean surface with no residue, which is what paint and coatings need to bond.
KBS Klean is non-corrosive and non-toxic, and it cleans ferrous and non-ferrous metals, plastics, stone, brick, masonry, canvas, asphalt and other materials. For brake parts in particular, see Can KBS Klean Be Used as a Brake Cleaner?
What You Need
- KBS Klean: the cleaner and degreaser, diluted with hot water
- Hot water, and a sponge, scrub pad or bristle brush
- RustBlast (bare metal only): the etch that follows cleaning. Skip it on plastic, masonry and fully cured paint
- Chemical-resistant gloves, safety glasses and proper personal protective equipment
How to Clean a Surface with KBS Klean Before Painting
To clean a surface before painting, dilute KBS Klean with hot water, wash the surface for 5 to 10 minutes, rinse thoroughly with water and let it dry. The complete procedure is in the KBS Klean directions.
- Dilute KBS Klean with hot water. Mix KBS Klean with warm or hot water at the ratio that matches the soil level. Pre-paint cleaning is 5 parts hot water to 1 part KBS Klean. Aluminum, copper and brass get 25 parts hot water to 1 part KBS Klean.
- Apply and scrub. Apply the solution with a sponge, scrub pad or bristle brush. KBS Klean also runs through pressure washing equipment, which cuts through layers of built-up grime quickly.
- Wash for 5 to 10 minutes. For general purpose cleaning, wash the surface for 5 to 10 minutes or as long as needed to produce a clean surface. Heavily soiled parts may need an extended soak of up to 24 hours or more. Do not let KBS Klean dry on the surface.
- Rinse thoroughly with water. Rinse the surface thoroughly with water.
- Let the surface dry. Let the surface dry completely before the next step.
- Etch bare metal with RustBlast. On bare metal, treat the cleaned surface with RustBlast before painting to ensure proper adhesion. Then apply your coating.
Stuck or unsure? Search the KBS Support Desk for instant answers
KBS Klean Dilution Ratios
KBS Klean is mixed with hot water at 1 to 1 for heavily soiled surfaces, 5 to 1 for pre-paint cleaning, 10 to 1 for light soil and 25 to 1 for non-ferrous metals. Follow these ratios. More detail is on the KBS Klean dilution ratios page.
| Heavily soiled surfaces (diesel engines, fuel tanks) | 1 part hot water to 1 part KBS Klean |
|---|---|
| Moderately soiled surfaces (pre-paint cleaning) | 5 parts hot water to 1 part KBS Klean |
| Lightly soiled surfaces (truck road film) | 10 parts hot water to 1 part KBS Klean |
| Non-ferrous metals (aluminum, copper, brass) | 25 parts hot water to 1 part KBS Klean |
A cleaner should not stain the surface, especially where the metal will show through a clear coat. Most aggressive cleaners will stain non-ferrous metals. KBS Klean will not stain non-ferrous metal when it is mixed at the correct ratio. See KBS Klean on bare aluminum for more.
Frequently Asked Questions About Cleaning Before Painting
Is it okay to use brake cleaner before painting?
KBS does not recommend it. Brake cleaner is a solvent-based cleaner, and solvent-based cleaners can leave an invisible residue that interferes with paint adhesion and appearance. Wash the part with KBS Klean diluted in hot water, rinse thoroughly with water, and let the surface dry completely before you paint. If you have already used brake cleaner, that KBS Klean wash is what removes the residue.
What is the best thing to wipe a car down with before painting?
Wash the surface with a water-based cleaner and degreaser such as KBS Klean, mixed 5 parts hot water to 1 part KBS Klean for pre-paint cleaning. Rinse thoroughly with water and let the surface dry. KBS Klean rinses away completely, so no residue is left to interfere with the paint.
What is the best thing to clean metal with before painting?
KBS Klean is the cleaner KBS recommends for metal before painting. It is a concentrated, water-based cleaner and degreaser that removes dirt, grime, oils, lubricants, grease and waxes and leaves no residue. On bare metal, follow the cleaning step with RustBlast before painting to ensure proper adhesion.
Is brake cleaner just isopropyl alcohol?
No. Brake cleaner is a blend of solvents, and the blend varies from product to product. Some non-chlorinated brake cleaners list isopropyl alcohol along with other solvents such as acetone and hexane. The safety data sheet for a brake cleaner lists what is in it.
Does brake cleaner remove paint?
It can. At least one brake cleaner maker warns on its product sheet that the cleaner may instantly damage paint and some plastics, and says to avoid contact with automotive finishes. Keep brake cleaner away from any painted surface you want to keep. KBS Klean will not harm a fully cured coating when used according to the directions.
Do I need to etch metal after cleaning it with KBS Klean?
Yes, on bare metal. Metal surfaces cleaned with KBS Klean should be treated with RustBlast before painting to ensure proper adhesion. RustBlast removes rust, etches the metal and leaves a zinc phosphate coating for the paint to grip.
What ratio of KBS Klean do I use on aluminum?
Mix 25 parts hot water to 1 part KBS Klean for aluminum, copper, brass and other non-ferrous metals. Most aggressive cleaners will stain non-ferrous metals, and KBS Klean will not stain them when it is mixed at that ratio.
More answers are in the KBS Klean FAQs.
Still have questions? Search the KBS Support Desk for instant answers
After the Surface Is Clean
A clean, residue-free surface is the first step, and on bare metal the etch comes next: treat it with RustBlast, then apply your coating, whether that is Motor Coater on calipers and engine parts or RustSeal on a frame or floor pan. If you have questions about cleaning a surface before painting or coating, contact us.
Related guides: How to Prepare Metal for Painting for a Durable Finish, How to Detail Your Engine and Engine Bay with KBS Klean, The Best Way to Paint Brake Rotors and Restore Brake Rotors, or browse all KBS application guides.
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