The MGA With An Attitude
SHIMMING ADJUSTER MASKS When Shoes Are Too Small - BT-212
Saturday, August 26, 2023:
Going to do more brake work on the car today, determined to reduce the backlash in the brake adjusters. Something I have been resisting doing for at least 10 years, as we were trying to coerce the vendors into supplying correct length brake shoes. Unfortunately it hasn't been working, and likely never will, so now we get to show the world how to fix it. These shims are made from 1/8-inch thick steel plate, cut to 9/16" wide and 1-1/8" long, to be tack welded to the adjuster masks. Each front drum brake adjuster gets one shim, two adjusters per wheel, because there are two slave cylinders up front. Each rear drum brake adjuster gets two shims for 1/4-inch total thickness, one adjuster per wheel, because there is only one slave cylinder in back to move two shoes, and the one double thickness shim is working to space out two brake shoes.
Clamp the shim plate to back of the adjuster mask, mount it in the vice, tack weld one end. Then turn it around to tack weld the other end. Rinse and repeat 6x. Grind the back plates flat, and touch off the ends. File away or grind out any weld that happened to obstruct the inside corners, so the adjuster can seat properly at zero. Finish by adding a second layer shim to two of the masks that will be used for the rear brakes.
Starting at the LF brakes with the newly shimmed adjuster masks. They worked like a charm to bring the shoes up very close to the previously new brake drum. After installing the adjusters and shoes and the drum, each of the adjusters ran up just 2 clicks before the shoes locked the brakes, and back them off one click please. On the right side, remove brake drum to install the new shimmed adjuster masks, get it back together, and run the adjusters up 2 clicks just like the left side. This was looking very good. Front brakes back together, bleed the front lines and get the car back on the ground.
Jack up the rear end to remove wheels and brake drums to swap in the new double shim adjuster masks. While I was doing that, brother was cleaning the new drums with lacquer thinner and let dry, and navigator was spraying them with some heat resistant black paint. That would be a good rime for a late lunch break while paint was drying.
After lunch and paint dry, I did paint the rear hubs to match the new drums. Then with the drums back on, the adjusters ran up 3 or 4 clicks before the brakes locked up, and back them off one click please, very nice. Bleed the rear brakes just to flush fresh fluid through front to back (at least once every two years). Top up the reservoir, check for good brake pedal short travel and firm stop, all good. Wheels back on, car on the ground, clean up and pack away tools.
|