A brake pedal that sinks too low or travels excessively before applying the brakes often indicates that the gap between brake lining and brake drum is ________.
excessive
In a drum brake there is a designed clearance between the brake lining and the drum, and the pedal must first take up this gap before the shoes press on the drum.
This gap take-up is what the early part of the pedal travel is spent on, before hydraulic force actually applies the braking.
If the gap becomes too large, the pedal has to move a long way to close it, so it sinks low and travels excessively before the brakes bite.
A properly adjusted gap would give a firm, high pedal with normal travel, so that option contradicts the symptom described.
A too small or zero gap would keep the linings almost touching the drum, causing brake drag or a very firm pedal, not excessive travel.
Therefore a low, long-travelling pedal points specifically to an excessive lining-to-drum clearance.
Hence, the answer is excessive.
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