Brake Fluid Flush & Bleed

Brake fluid is hygroscopic — it absorbs moisture from the air over time. After two years, the moisture content in DOT 4 fluid is high enough to measurably lower its boiling point and promote internal corrosion in calipers, master cylinders, and brake lines. Old brake fluid also makes for spongy lever feel as dissolved water creates micro-bubbles in the system. A fluid flush every two years is inexpensive insurance for a safety-critical system.

What's Included

• Front master cylinder reservoir cleaned and inspected
• Rear master cylinder reservoir cleaned and inspected
• Fresh DOT 4 fluid introduced
• Both front calipers bled until fresh fluid exits with no bubbles
• Rear caliper bled
• All bleed nipples checked for sealing
• Lever feel test — firm and consistent through full stroke

DOT 3 vs DOT 4 vs DOT 5

Harley-Davidson specifies DOT 4 in almost all models. Never use DOT 5 (silicone-based) in a system designed for DOT 3/4 — they're incompatible and mixing creates a gummy compound that destroys seals. If you're unsure what fluid is in your system, flush the entire system with fresh DOT 4.