Brake Release Tool for Husqvarna Chainsaw

A typical mistake by new users is to remove the clutch cover on a chainsaw without first releasing the chain brake. That makes getting the clutch cover back onto the saw impossible until the brake band has been relaxed. Using a castle nut I made a simple tool for relaxing the brake band. There is no welding.

Materials

• A castle nut that requires a 3/4 inch or 19mm wrench

Tools

• Angle head grinder with cutting disc

Look closely at the photo. While the cutting wheel whittles away a raised portion (parapet) near the operator the rest of the cutting wheel is aimed in order to be in the opening on the other side of the nut. Try not to grind any of the parapets on either side of the opening where the cutting wheel is positioned so as not to cut. Remove every other parapet.

When I had finished grinding away three alternating parapets the castle nut would still not fit down over the three-arm brake release wheel. I needed to thin the inside faces of the remaining parapets just a little. See the second photo for how the castle nut should fit over the three-arm release wheel.

Place the modified castle nut into the sparkplug socket on the scrench (SCrewdriver + wRENCH) tool that came with the chainsaw. Place the scrench with modified castle nut onto the three-arm release wheel. Brace the cover plate and rotate the wrench until the three-arm release’s mechanism clicks to indicate the brake band has been relaxed.

Sometimes it is helpful to remove the clutch cover and set the brake band to its contracted position. This is especially useful when cleaning oily sawdust from the inside of the clutch cover. Just a little sawdust behind the brake band keeps it from its fully relaxed position and increases drag on the clutch. Placing the brake band into its “set” position makes cleaning behind the band much easier.

The third photo shows a welded version I made before I thought of using a castle nut I found in a junk box. It might be helpful to you if you have access to a welder and have difficulty finding a suitable castle nut. I placed the nut into a vise so one face was above the jaws the thickness of 1/8 x 1/2 inch steel bar. I rested the steel bar on the top of the vise jaw and welded its end to the nut. Then I cut the bar away to leave about 1/8 inch from what I welded. I repositioned the nut for the next of three faces to receive the welded bar. When I had welded the three needed faces and cut the bar to length I used a file by hand to put a 60 degree point on the welded pieces.