The number 10.090 cast into the brake drum refers to which specification?

The number 10.090 cast into the brake drum refers to which specification?

• A. Discard/Maximum Diameter
• B. Outer Circumference
• C. Minimum Diameter
• D. Bolt Circle Size

Answer: (A)

The number cast on a brake drum shows the discard, or maximum, diameter. It’s the largest diameter the drum is allowed to have and still be considered usable. If the drum wears down to that size (or is machined to it), it must be replaced because there’s no safe material left to maintain proper clearance and strength. This isn’t an outer circumference or bolt pattern spec, and the minimum diameter is a different limit used to judge wear, not the cast number you’d read on the part.

The number cast on a brake drum shows the discard, or maximum, diameter. It’s the largest diameter the drum is allowed to have and still be considered usable. If the drum wears down to that size (or is machined to it), it must be replaced because there’s no safe material left to maintain proper clearance and strength. This isn’t an outer circumference or bolt pattern spec, and the minimum diameter is a different limit used to judge wear, not the cast number you’d read on the part.