Brake Fluid Comparison

Aston Martin's factory brake fluid is Castrol React Performance. It's a good street fluid but might not hold up on the track. Motul DOT 5.1 is comparable to the Castrol but with slightly higher boiling points. You can easily upgrade to Motul RBF600 for better performance. An added bonus is that both of these Motul fluids are actually less expensive than dealership pricing for the OEM Castrol fluid. If you need to go beyond that, Motul RBF660 has a higher dry boiling point. Castrol React SRF Racing is probably the best DOT-approved fluid on the market. But be warned, you'll pay for it - it's 3x the cost of RBF600 and 2x the cost of RBF660!

I sell all of Motul's braking fluids in my online store.

Wet vs Dry Boiling Points

The easiest way to understand boiling points is to think of the dry boiling point as the temperature that brake fluid can handle when it's brand new. The wet boiling point is the temperature it can handle when it's at the end of its life, either due to heavy use or age - both of which are incredibly important when determining the service life of a brake fluid.

Brake Fluid Options

Castrol React Performance (OEM brake fluid)

Viscosity at -40°C 1200 mm2/s
Density at 20°C 1.07 g/ml
Wet boiling point 180°C min
Dry boiling point 260°C min

Motul DOT 5.1 (Comparable to the OEM brake fluid)

Viscosity at -40°C 820 mm2/s
Viscosity at 100°C 2.1 mm2/s
Wet boiling point 185°C min
Dry boiling point 272°C min

Motul RBF600

Viscosity at -40°C 1750 mm2/s
Viscosity at 100°C 2.5 mm2/s
Wet boiling point 205°C
Dry boiling point 312°C

Motul RBF660

Viscosity at -40°C 1698 mm2/s
Viscosity at 100°C 2.59 mm2/s
Wet boiling point 204°C
Dry boiling point 328°C

Castrol React SRF Racing

Viscosity at -40°C 1300 mm2/s
Viscosity at 100°C 3.5 mm2/s
Density at 20°C, relative 1.066 g/ml
Wet boiling point 270°C min
Dry boiling point 320°C min