Today's cars, SUVs and pickups are powerful; as a consequence, they are assembled with better and more robust brake systems. Several factors can increase the operating temperature of the brake system: braking hard or repeatedly, carrying a heavy load, mountain driving, driving in stop-and-go traffic, towing a trailer, etc. Under those extreme conditions, lubricants have to withstand the heat without melting or burning off. Also, in normal duty conditions, the grease has to not harm the rubber seals or plastic bushings. For this reason, petroleum-based lubricants should never be used for brake assemblies because this kind of lubricant can degrade the system seals and cause a brake failure. Another reason to not use this type of grease is that if melted, the runoff can contaminate the friction material, which could also cause a brake failure.