Hydraulic disc brakes reward you for the maintenance you actually do and punish you for the maintenance you skip — and brake fluid sits at the top of that list. Four-ounce (120ml) bottles of SRAM DOT 5.1 fluid are available in most regions using part number 00.5318.017.000 , and this is the factory fluid to keep on the bench for bleeds and top-offs across the SRAM and Avid hydraulic lineup. If your lever throw has gotten longer, the bite point has gone soft, or you're overdue for a service interval, this is the fluid that goes back into the system.

DOT 5.1 is glycol-based, not silicone, and that chemistry matters. The formula is hygroscopic, meaning it pulls moisture out of the atmosphere over time, which lowers the boiling point and introduces the spongy lever feel that tells you a bleed is overdue. That's the tradeoff for the higher performance ceiling — DOT 5.1 has a higher boiling point than DOT 4, but must be changed more frequently due to faster water absorption . Fresh fluid restores the firm lever and consistent bite point that the system was designed around.

Compatibility is broad within the DOT ecosystem. This fluid is compatible with all SRAM and Avid hydraulic disc brakes , which covers Level, DB, G2, Guide, Code, Maven, and the hydraulic road brake calipers on Red, Force, Rival, and Apex AXS. Do not use it in Shimano, Magura, or any brake system that specifies mineral oil — mixing fluid types will destroy the internal seals and require a full caliper and lever rebuild.... Read More