Replace Brake Light Switch Harley Ironhead Sportster
(Front and Rear)
On 1973-up Sportsters, the front brake switch is mechanical and located inside the right handlebar control. The rear brake switch can be either mechanical (mounted on brake rod) or hydraulic (threads into brake tee). No special tools are required to replace them.
Front Drum Models
Sportsters did not have a front stop light switch until mid-1969. Before that, the brake light was activated solely by the rear switch.
From mid-1969 up through 1972 XL (and 1971/1972 Super Glides), there was a provision for a switch (HD 71900-70) in the brake lever.
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Front Brake Switch Replacement
To get started, lay a towel over the gauges or have a tall chair next to the handlebars. This will give you a place to work while taking out the old switch.
On early bikes, unscrew the old switch from the lever. On 1973-up bikes, remove the two screws holding the right-hand handlebar control housing together.
Pulling off the two spade terminals reveals the old switch.
Remove From Housing
The switch is plastic and threaded into the housing with 1/4-32 threads.
It's a tight fit to unscrew it. A pair of needle-nose pliers work well.
Replacement Switch
Milwaukee Twins front stoplight switch fits 1973-1979 XLCH, 1974-1981 XLH, 1977-1978 XLCR Cafe Racer, and 1977-1978 XLT.
This switch is a direct replacement for obsolete H-D #'s 72001-69A and 72001-69B.
Also fits 1971-1981 Harley FX/FXE, 1980, 1981 Sturgis and Wide Glide, and other Big-Twins.
Installing the new switch is reverse of removal. Attaching the two wires and installing the rubber cover can be difficult.
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Brake Switch Replacement Rear (Mechanical)
Harley XL models up to 1976 have a rear brake rod. The rear stoplight switch is mechanical (momentary on-off push-button).
Pictured: 1974 XLH Sportster with switch mounted on the brake pedal rod.
Rear Brake Switch Diagram 1959-1978 Sportster
Fig 30: Rear Brake Switch For Sportster 1959-1966 (replaces OEM 72004-52)
Fig 31: Rear Brake Switch For Sportster 1967-1974 (replaces OEM 72003-34)
Fig 32: SRear Brake Switch For Sportster 1975-1976 (replaces OEM 72004-75)
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When Ironhead engine cases were redesigned for 1977, a cable replaced the metal brake rod, and stayed in use until rear discs became standard in 1979. The rear switch was now 72001-69B (same as the front switch).
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Rear Switch (Hydraulic)
On 1979 and later Sportsters (and early FX models), the rear brake switch is hydraulic, and threads into a brake tee.
Standard Motor Products Brake Switch fits 1979-1985 Sportsters and several 1971-up Big-Twin models.
TIP: Before removing the old switch, hold the rear brake pedal down slightly with a bungee cord. This will create a light sealing tension and will minimize fluid loss/air entry when replacing switch.
Pull off the two wire terminals and unscrew old switch with a wrench. Have a rag handy for brake fluid drips.
Thread in new switch by hand, then tighten with wrench.
TIP: Before installing new switch, apply thread sealant to the threads.
Attach wires back to terminals (polarity does not matter). Release the bungee cord, pump the pedal and check for leaks. Turn the key to test the lights.
Note: If the pedal feels spongy afterward, you may need to bleed the rear brake line.
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Custom Brake Light Switch
Here's a custom brake switch fabricated for a hardtail Ironhead with rear disc.
A brass tee was mounted underneath the frame behind the motor.
Related Article: Hardtail Sportster Build
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Related Articles:
Rebuild Harley Master Cylinder
Harley Caliper Overhaul 1973-1977
Rebuild Harley Dual Disc Calipers (1977-1983)
Remove Stuck Brake Piston
Sportster History
