We’re all guilty of it, right? You start spraying brake cleaner on… well, the brakes, because that’s what it’s for. But then you notice how well it seems to make grease and grime disappear from virtually every surface it touches. You can’t help yourself, so you keep going. A shot on the engine block to clean up that leaking valve cover gasket. A blast on the suspension parts to erase all the greasy residue that somehow coats every surface. Before you know it, you’ve drained an $8 can of cleaner and you’re tearing apart the garage for another one. Price be damned, this stuff works on everything!
Traditional brake cleaner does indeed seem like a magical elixir, but its shouldn’t be used for every filthy part on your project. Typically a blend of perchloroethylene, methylene chloride, and naphtha petroleum, it’s highly effective at dissolving oils, it flashes off quickly, and it’s non-flammable. It’s the first component – perchloroethylene, often referred to as PERC or PCE – that does the heavy lifting though. Its ability to disperse grease and oil is legendary, which is why it’s popular with dry cleaners as well.
Effective but risky
But for all its advantages, PERC is also a highly toxic chemical to work with. In December 2022, the US EPA found it presents an unreasonable risk to health under its conditions of use. Exposure to eyes, skin, and the respiratory system can lead to cancer. Perhaps that’s why California and New Jersey have already banned its use. And while it’s not uncommon to see a technician wearing gloves while working, rarely do you see one wearing breathing protection or goggles when spraying brake cleaner.
Beyond the standard health risks, chlorinated brake cleaner poses a unique hazard to those who weld. When heated to temperatures required for welding, a chemical reaction occurs that breaks down PERC into hydrogen chloride and phosgene. These two extremely poisonous gases can knock a person down instantly and result in permanent respiratory damage. An article on thefabricator.com chronicles the hazards of prepping metal for welding using brake cleaner. It’s not to be ignored.
Alternatives
In response to the inherent risks associated with chlorinated brake cleaner, safer alternatives were eventually developed. These non-chlorinated formulas, often identified as ‘low-VOC’ (for “low volatile organic compounds”), are typically composed of acetone and heptane. Though neither as aggressive as PERC nor inflammable, they’re nevertheless quite effective as brake cleaning solvents. They’re also less hazardous without the presence of chlorine, making them suitable for welding preparation.
However, even non-chlorinated brake cleaner isn’t the end-all, be-all for every cleaning job. A variation on this solvent-based formulation with more universal applications is chassis cleaner, such as Eastwood’s Chassis Kleen. This is safe on all chassis components such as suspension, drivetrain, and brakes.
Another option for these systems would be a detergent-based degreaser like Eastwood’s Concours Orange Surge. These work like laundry soap, breaking down grease more gently, particularly on some painted surfaces or around sensitive electrical parts. A milder detergent cleaner intended primarily for surface preparation rather than heavy cleaning is Eastwood’s Pre Green pre-painting prep. This is a non-toxic, not flammable treatment that requires no rinsing, making it suitable for plastics as well as bare metal. It also comes in handy ready-to-use wipes.
For most other light surface degreasing, our standby is always Eastwood’s Pre painting prep in either original or low-VOC formula. Either can be sprayed or wiped onto work before painting. We prefer the low-VOC formula for welding prep as it flashes off faster, allowing you to work almost immediately.
So keep on using your trusty brake cleaner to clean those brake components. But maybe give a second thought before you spray it on everything else. And certainly don’t use the old-school chlorinated stuff on your welding project, especially if you want to finish it.
Who knew, good to know, thank you will do.