Servicing the brake
How is the engine's brake serviced?
A well-maintained braking system should stop the engine and any attached cutting equipment within three seconds whenever you step away from the equipment or release the brake bail. A brake bail is standard equipment on today's mowers, tillers and other walk-behind equipment. The stop switch immediately grounds the ignition, shutting off the engine, while a brake pad or band stops the flywheel from spinning.
If the engine operates for more than three seconds after the bail is released, the stop switch may be faulty. If the blade spins for more than three seconds, the brake pad or band may be worn or in need of adjustment.
Current models use a brake pad that requires no adjustment. Some older models use a brake band, which may require adjustment by an authorized service technician. This section covers the replacement procedures for the brake band and pad styles.
Removing A Brake Pad
- Remove the spark plug lead and secure it away from the spark plug. Then, remove any other components that block access to the brake, such as the finger guard, fuel tank, oil fill tube (image A), blower housing or rewind starter (image B).
- Remove the brake control bracket cover (image C), if equipped. Then, loosen the cable clamp screw and remove the brake cable from the control lever.
- Disconnect the spring from the brake anchor, using needlenose pliers (image D). Then, remove the stop switch wire from the stop switch by gently squeezing the switch and pulling lightly on the wire until it slips free. If the engine is equipped with an electric starter motor, disconnect the pair of wires leading to the starter motor.
- Loosen the brake bracket screws and remove the bracket from the brake assembly.
Inspecting And Testing
- Inspect the brake pad for nicks, cuts, debris, and other damage. Check for wear, by measuring the pad's thickness with a ruler or caliper (image A). NOTE: Measure the pad only,
not the bracket. Replace the brake assembly if the pad's thickness is less than .090".
- Test the stop switch, using a multitester or ohmmeter, to determine whether the ignition circuit is grounded when the stop switch is activated (image B). The stop switch should show continuity (0 ohms) to engine ground when the switch is set to STOP, and no continuity (∞), when the switch is set to RUN. If you identify a problem, check for loose or faulty connections.
Reassembling The Braking System
- Install the brake assembly on the cylinder (image C). Tighten the mounting bolts to 40 inch. lbs., using a
- Install the stop switch wire, bending the end of the wire 90° (image D).
- Install the blower housing and any other engine components removed for brake servicing.
- Check the braking action by pivoting the lever. Make sure the lever moves freely and the pad makes full contact with the flywheel.
- Attach the brake spring, using needlenose pliers, and connect the brake cable that connects to the brake bail on your walk-behind equipment.
- Test the braking system by starting the engine and then releasing the brake bail. The engine and the blade or other equipment should come to a stop within three seconds. If you are uncertain about the effectiveness of your braking system, bring the equipment to your Authorized Dealer for further inspection.
Removing and Inspecting A Band Brake
The brake band contains loops at either end, mounted on a stationary and a movable post. A tang over the movable post prevents the brake band from dislodging during operation.
- Use a tang bending tool to bend the control lever tang outward so it clears the band brake loop (image A).
- Release the brake spring using pliers (image B).
- Lift the band off the stationary and movable posts (image C).
- Inspect the band for damage. Replace it if you find nicks or cuts.
- Check for wear by measuring the pad's thickness with a ruler or caliper (image D). NOTE: Measure the pad only, not the metal band. Replace the brake band if the pad's thickness is less than .030" (image D).
Testing A Band Brake
Test the band brake's stopping power with the spark plug lead secured away from the spark plug. On electric start engines, disconnect and remove the battery.
- With the brake engaged, turn the starter clutch, using a starter clutch adapter and torque wrench (image E). Turning the flywheel clockwise at a steady rate should
require at least 45 inch lbs. or toque. If the torque reading is lower, components may be worn, damaged or in need of adjustment.
- Test the stop switch, using a multitester or ohmmeter, to determine whether the ignition circuit is grounded when the stop switch is activated. The stop switch should show continuity (0 ohms) to engine ground when the switch is set to STOP, and no continuity (∞) when the switch is set to RUN. If you discover a problem, check for loose or faulty connections.
Assembling A Band Brake
- Reinstall the stop switch wire on the control bracket. On older systems, reinstall the stop switch wire on the control bracket stop switch terminal.
- Place the band brake on the stationary post and hook it over the end of the movable post until the band bottoms out. NOTE: The brake material on a steel band must be on the flywheel side after assembly. On older systems, install the band brake on the stationary and movable posts.
- Bend the retainer tang until it is positioned over the band brake loop so that the loop cannot be accidentally dislodged. After assembly, check that the braking material on the metal band faces the flywheel.
NOTE: Please read and abide by any applicable Safety Information (PDF) before performing any engine work. This information is not meant to take the place of work performed by a Briggs & Stratton Authorized Dealer. Terms and Conditions apply to all of our information provided on this website. Always be sure to read and understand your engine Operator's Manual.
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