Brake cleaner is an essential product for DIY mechanics and professional auto shops alike. This powerful solvent easily breaks down oil, grease, brake fluid, and other contaminants from brake pads, rotors, calipers, and other brake components.
However, as useful as brake cleaner is, you have to be careful where you use it. One common question is: is brake cleaner safe on rubber components?
Here’s a quick answer: No, brake cleaner is generally not safe on rubber components. The strong solvents in brake cleaner can damage many automotive rubber parts like hoses, seals, bushings, and tires. Brake cleaner can degrade rubber by dissolving antioxidants and accelerators added during manufacturing. Use specialty rubber cleaners instead.
Read on to learn why brake cleaner and rubber don’t mix, what kind of damage it can cause, and how to properly clean rubber automotive parts.
How Does Brake Cleaner Work?
Before we dive into whether or not brake cleaner damages rubber, it helps to understand what exactly brake cleaner is and how it works.
Brake cleaner is a fast-drying solvent blend designed to break down oil, grease, brake fluid, and other substances. Most brake cleaners contain a mixture of the following active ingredients:
- Acetone – A powerful solvent that breaks down oils and dissolves some plastics.
- Methanol – Helps acetone dissolve oil-based contaminants.
- Toluene – Another strong solvent often used as a paint thinner.
- Carbon dioxide – Added as a propellant to spray brake cleaner.
Some brake cleaners also contain ingredients like xylene, methyl acetate, and 1,1,1-trichloroethane. However, the formulas vary between brands.
When you spray brake cleaner on a dirty brake component, it immediately goes to work breaking down and dissolving oil, grease, and other gunk. The solvents quickly evaporate, carrying away the dissolved contaminants and leaving behind a clean surface.
Brake cleaner is specially formulated to be safe on metal components. But as you’ll see, rubber is a different story.
Why Brake Cleaner Damages Rubber
Brake cleaner can degrade, swell, harden, or outright melt many types of rubber components. But why?
To understand why brake cleaner damages rubber, you need to know a bit about how rubber is made. Natural rubber obtained from rubber trees doesn’t have the right properties on its own to make durable rubber components. So, chemicals are added to improve the quality of the raw rubber.
Two of the most important chemicals added are accelerators and antioxidants:
- Accelerators – Help the raw rubber vulcanize (harden) during manufacturing. Accelerators often contain chemicals like thiazoles, sulfenamides, thiurams, and dithiocarbamates.
- Antioxidants – Protect the finished rubber component from ozone damage. Common antioxidants include waxes and phenolic compounds.
The strong solvents in brake cleaner can break down, dissolve, or react with these rubber additives:
- Accelerator breakdown – This leads to loss of elasticity, hardness, and strength in the rubber.
- Antioxidant removal – Rubber loses its protection from ozone damage. This leads to surface cracking over time.
So in short, brake cleaner damages rubber by interfering with the chemicals that give rubber its useful properties.
What Rubber Parts Can Be Damaged?
Brake cleaner can potentially damage many rubber components under the hood, in the braking system, and elsewhere on your vehicle. Some specific examples of vulnerable rubber parts include:
Radiator hoses, heater hoses, vacuum hoses, and fuel hoses are all at risk of damage from brake cleaner. The serpentine belt and timing belt contain rubber that can also be degraded.
Various gaskets and seals like valve cover gaskets, oil pan gaskets, axle seals, and differential seals are not compatible with brake cleaner. Control arm bushings, sway bar bushings, strut bushings, and other suspension bushings can also be harmed.
Additionally, engine mounts, tires, brake hoses, caliper seals, and wheel cylinder seals all contain rubber materials that brake cleaner could damage. Essentially any rubber components under the hood or in the braking system should be kept away from brake cleaner.
As you can see, brake cleaner could easily ruin critical rubber components if sprayed in the wrong place.
What Kind of Damage Can Occur?
Depending on the type of rubber, exposure, and other factors, brake cleaner can cause several types of damage:
- Surface cracking – Antioxidant removal leads to surface ozone cracking over time.
- Loss of strength and flexibility – Rubber hardens as accelerators are broken down.
- Swelling – Rubber absorbs solvents and swells up. This can interfere with proper fit and sealing.
- Melting – Particularly soft rubber compounds can melt when exposed to high concentrations of brake cleaner solvents.
- Adhesive failure – Bonds between rubber and metal components weaken.
- Flaking and peeling – Outer layers of rubber peel away after solvent exposure.
- Cracks and tears – Rubber splits open as chemicals leach out.
- Leaks – Seals, gaskets, and hoses leak as rubber loses flexibility and adhesion.
- Premature failure – Weakened rubber components fail before they should.
While a quick wipe probably won’t cause catastrophic failure, repeated exposure to brake cleaner will deteriorate sensitive rubber parts over time.
Signs of Brake Cleaner Damage
How can you visually spot brake cleaner damage on rubber components? Here are some telltale signs to look for:
- Cracking or crazing on the surface
- Visible swelling
- Peeling or flaking outer layers
- Loss of elasticity (doesn’t snap back when stretched)
- Hard or brittle spots
- Gummy residue
- Unusual softness or mushiness
- Cracked edges
- Greasy spots where chemicals leached out
If you see any of these warning signs, the rubber part has likely been compromised by brake cleaner exposure.
Is Brake Cleaner Ever Safe on Rubber?
While brake cleaner is generally harmful to most rubber compounds, there are a few cases where limited use may be acceptable:
- Rubber tires – Tire rubber is highly resistant to chemicals. Brief wipe downs to remove grease should not cause issues. Avoid prolonged exposure.
- Silicone and Viton rubber – These specialized types of synthetic rubber have excellent chemical resistance. Brake cleaner use may be acceptable.
- Rubber brake lines – The outer rubber coating of brake hoses can withstand moderate exposure. But avoid soaking the hoses in cleaner.
However, aside from these exceptions, rubber parts should always be protected from brake cleaner. The risks outweigh any benefits.
How to Properly Clean Rubber Parts
Instead of brake cleaner, here are some safe, rubber-friendly ways to clean automotive hoses, seals, bushings, engine mounts, and other components:
1. Rubber Cleaner
Rubber cleaner is specifically designed for use on rubber components. It contains detergents rather than harsh solvents, making it safe for all rubber parts. Rubber cleaner also provides UV protection.
2. Mild Soap and Water
Use a mild hand or dish soap, not a degreaser, when cleaning rubber components. Gently scrub with a soft brush, then rinse thoroughly with clean water. Make sure to dry the parts completely when finished cleaning.
3. Rubbing Alcohol
Rubbing alcohol is much milder than brake cleaner solvents. It evaporates quickly and doesn’t leave any residue behind. For best results, use a 70% isopropyl alcohol solution.
4. Non-Chlorinated Brake Cleaner
You can also find specialty brake cleaners marketed as “safe for rubber” that do not contain chlorinated solvents. Test it on a small area first before use.
When cleaning rubber parts, take your time and clean them gently by hand. Avoid pressure washing or soaking the rubber in strong degreasers and cleaners. The right cleaning methods will remove dirt and grease without compromising the integrity of the components.
Here are answers to some frequently asked questions about using brake cleaner on rubber automotive parts:
Can I use brake cleaner on rubber hoses?
Avoid it. The outer rubber coating on hoses may withstand moderate exposure. But it’s still best to use a rubber-safe cleaner instead of risking damage.
What about brake caliper seals?
Brake caliper seals are particularly vulnerable to brake cleaner damage due to their constant exposure to brake dust and fluids. Use extreme caution and wipe down gently with isopropyl alcohol instead.
Will a little brake cleaner hurt my radiator hoses?
Even a little brake cleaner can start degrading sensitive radiator and heater hoses over time. Don’t risk expensive damage—keep brake cleaner far away from rubber hoses.
Can I clean my serpentine belt with brake cleaner?
No, the rubber compound in serpentine belts will be damaged by brake cleaner. Use a mild soap solution instead.
Is it OK to wipe down my tires with brake cleaner?
Tire rubber is quite resistant to chemicals, so a quick once-over to remove grease should not cause major issues. But still limit exposure as much as possible.
The Bottom Line
While brake cleaner is a shop staple, it should be kept far away from most rubber components due to potential damage. Limit brake cleaner to metal brake parts only. When cleaning rubber components, reach for specialty rubber cleaners, mild soap and water, isopropyl alcohol, or non-chlorinated brake cleaner instead. With some care, you can keep your car’s rubber parts looking and functioning their best.