How should the angle between the push rod and adjustor arm be when brakes are released?

When brakes are released, the ideal angle between the push rod and the adjustor arm should be just over 90 degrees. This positioning indicates that the slack adjuster is properly set and that there is adequate space for the brakes to function without being engaged. A push rod and adjustor arm angle of just over 90 degrees suggests that the brake shoes are slightly retracted from the drum, allowing for effective braking performance and ensuring that the brake system does not remain engaged, which could lead to wear or overheating.

An angle of exactly 90 degrees would indicate that the brake shoes may be too close or even engaged with the drum, potentially leading to performance issues. An angle less than 90 degrees would indicate that the push rod may not be adequately providing the necessary leverage on the brakes, which could also affect performance negatively. Similarly, an angle less than 80 degrees would denote an even more diminished capacity of the adjustor arm to operate correctly, suggesting misalignment or improper adjustment of the braking system. Therefore, the just-over-90-degree angle signifies that everything is functioning in an optimal and safe manner.