Moving to part 2 of our coverage on checking for brake problems. If you missed part 1, you can read it here.
On dual servo brake system like the one shown, grasp the star wheel at the bottom of the shoes and swing the brake shoes right and left. You should be able to move the assembly easily and without any clicking or catching. If it doesn’t move easily after disassembly check the shoe pads on the backing plate for groves or the system for the wrong hardware kit.
Carefully check the top anchor to shoe contact area. The shoes must be fully seated against the anchor pin as shown. Also note if the return springs are installed correctly.
A quick glance at the rearward (secondary) brake show on the RR brake shows it is only making contact with the drum on the outer 10-15% of the shoe. This obviously is a problem but what is causing it?
The RR front (primary) brake shoe has a higher percentage of shoe contact area but still has a problem with improper shoe to drum contact area.
Note: Further examination will determine that the LR wheel lock up problem is not caused by any brake function of the LR but rather by lack of equal braking of the RR wheel. You obviously always need to stop and when all four wheels aren’t doing their share of the braking the wheel opposite the one not doing it’s share may appear to have a pull or lock up problem.
We will have more of the story on checking for brake problems next week for Tech Tricks Tuesday.
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