How to Tell Which Size Drum Brakes for a '99 Dakota

The 1999 Dodge Dakota comes with either nine-inch rear drums or 10-inch rear drums. There are five different varieties of 1999 Dakotas. Two of them offer four-wheel drive, while the other three feature rear-wheel drive (two-wheel drive). The other major difference between the varieties is the engine size offered. No matter which variety Dakota, they all may feature either the nine-inch or 10-inch drum system. To make it easier, however, no matter which Dakota, they all take the same brake drum part number, albeit nine-inch or 10-inch drum system.

Instructions

1

Park the Dakota on a hard, flat surface and place a wheel wedge block in front of one of the front tire treads.

2

Loosen the lug nuts of one rear tire with the tire iron by turning them counterclockwise one full turn.

3

Hoist the rear of the Dakota upward with the jack placed under the rear differential high enough to place the jack stand under the rear axle. Lower the jack until the axle is resting on the jack stand the the tire is elevated.

4

Remove the lug nuts and tire.

5

Scrub the hub facing of the brake drum with the wire brush, if necessary. Drums are exposed to the elements and environment and can become severely rust covered. On the outer ridge facing of the drum are stamped numbers in millimeters. Focus on the area with the numbers stamped on the ridge of the drum with the brush.

6

Obtain the millimeter size stamped on the side of the drum and enter the number into a calculator. Divide that number by 25.4. There are 25.4 millimeters in an inch, therefore the closer to nine inches would indicate a nine-inch braking system and the same applies for ten-inch systems. Some of the millimeter stamps on brake drums may feature maximum diameter -- also know as discard -- a machine-to size (this depends on the manufactured brand of the drum). Maximum diameter is as far as the drum is allowed to be machined to before it should be discarded (replaced), machine-to size if as far as the drum can be machined to without rendering it beyond the maximum diameter. Therefore, the formula may vary between brake drum manufacturers.