Which material is commonly used for high-temperature seal applications in brakes?

• A. Silicone
• B. Nitrile
• C. Viton
• D. Neoprene

Answer: (B)

High-temperature brake seals need an elastomer that stays flexible under heat and resists brake fluids. Fluorocarbon elastomers, like Viton (FKM), excel in both areas, handling high temperatures (often up to around 200 C in service) and resisting swelling or degradation from glycol-based brake fluids. This combination makes Viton a common, reliable choice for brake seals.

Silicone can handle heat but isn’t as resistant to brake fluids and can creep under load. Nitrile (NBR) resists oils well but has a lower maximum temperature and can swell with glycol-based fluids. Neoprene offers decent chemical resistance and moderate temperature tolerance but generally doesn’t match the high-temperature, brake-fluid performance of fluorocarbons.