HardDrive Chrome Rear Master Cylinder Kelsey Hayes 3/4 Bore for 1979-1984 Harley-Davidson FL FX XL
When the rear brake feel goes vague or the master cylinder shows its age, every stop becomes a question mark. This Kelsey Hayes reproduction restores the confident, progressive rear braking response these Shovelhead-era Harley-Davidsons were built with, giving riders the peace of mind that comes from factory-correct stopping power and a restoration-worthy presence under the frame.
Key Features
- Faithful reproduction of the original Kelsey Hayes master cylinder design for OEM-correct appearance and hydraulic feel
- Direct replacement for OEM part numbers 42453-80A and 42454-80A
- Arrives fully assembled and ready to install — no rebuild required
- Compatible with standard 1/8-27 NPT brake line fittings
- Correct 5/16″ mounting holes on 2.25″ centers match original factory mounting points
Technical Specifications
- Bore Size: 3/4″
- Inlet Size: 1/8-27 NPT
- Mounting Hole Diameter: 5/16″
- Mounting Hole Spacing: 2.25″ on center
- Length: 4″
- Width: 1.5″
- Height: 3.125″
- Construction: Chrome-plated cast aluminum
- OEM Cross-Reference: 42453-80A, 42454-80A
Fitment Notes
- All 1979 fitments apply to late production only; early 1979 models are not compatible
- 3/4″ bore is correct for stock single-piston calipers; use a 5/8″ bore unit with multi-piston aftermarket calipers
- Review the Fitment tab for the complete year and model breakdown
Paul H. –
Nice product