The chain brake on a Husqvarna chain saw wraps around the clutch assembly and stops the clutch from spinning when it is engaged. To engage or disengage the chain brake, the front handle must be connected to the lever and spring of the brake assembly. The brake must be reset properly before you can reassemble the handle. The chain brake is a vital safety feature designed to save lives -- do not operate the chain saw without the chain brake properly installed.
Things You'll Need
Push the front hand guard on top of the saw forward to engage the chain brake. Unscrew both the bolts holding the front hand guard in place to the engine. Unscrew the chain guide plate, next to the clutch assembly, and lift it away.
Disassemble the chain brake's cover plate by unscrewing the four retaining screws. Lift the cover away using the tip of the screwdriver; underneath you will see a lever arm and a bushing connected to the lever. Push the bushing down and remove the lever arm from its seat.
Disconnect the pressure spring from its rear seat. Slide the tip of the screwdriver underneath the spring's hook and wiggle it free while holding your hand in place over the spring. Slide the tip of the screwdriver underneath the toggle joint to which the spring is connected at the front. Pull the out toggle joint with the brake strap connected. Check the brake strap to make sure it's at least .8 mm thick.
Reposition the head of the toggle joint into the seat just behind the clutch assembly. Position the brake strap along the outer edge of the clutch and press it down into the recess. Lubricate the toggle joint with the engine grease and press it down into its seat next to the spring.
Grease and push the lever arm and bushing back into place. Hook the front end of the spring to the toggle joint. Hook the rear end of the spring to the hook on the engine. Place the chain brake cover back on top and tighten the four retaining screws.
Put the chain guide plate back in place and tighten its screws. Connect the front hand guard to its seat along the top and starter side of the engine. Tighten the two bolts with the screwdriver. Pull the front handle backward to deactivate the chain brake. Inspect the brake strap to make sure it stayed in position along the clutch assembly.