BOLT TYPE BRAKE CHAMBER DATA
Type | Effective area (sq. in.) | Outside dia. (in.) | Maximum stroke at which brakes should be readjusted |
A | 12 | 615/16 | 13/8 |
B | 24 | 93/16 | 13/4 |
C | 16 | 81/16 | 13/4 |
D | 6 | 51/4 | 11/4 |
E | 9 | 63/16 | 1d |
F | 36 | 11 | 21/4 |
G | 30 | 97/8 | 2 |
ROTOCHAMBER DATA
Type | Effective area (sq. in.) | Outside dia. (in.) | Maximum stroke at which brakes should be readjusted |
9 | 9 | 49/32 | 11/2 |
12 | 12 | 413/16 | 11/2 |
16 | 16 | 513/32 | 2 |
20 | 20 | 513/16 | 2 |
24 | 24 | 613/32 | 2 |
30 | 30 | 71/16 | 21/4 |
36 | 36 | 75/8 | 23/4 |
50 | 50 | 87/8 | 3 |
CLAMP TYPE BRAKE CHAMBER DATA
Type | Effective area (sq. in.) | Outside dia. (in.) | Maximum stroke at which brakes should be re-adjusted |
6 | 6 | 41/2 | 11/4 |
9 | 9 | 51/4 | 13/8 |
12 | 12 | 511/16 | 13/8 |
16 | 16 | 63/8 | 13/4 |
20 | 20 | 624/32 | 13/4 |
24 | 24 | 77/32 | 13/4 1 |
30 | 30 | 83/32 | 2 |
36 | 36 | 9 | 21/4 |
1 Note (2 inches for long stroke design)
Wedge Brake Data. Movement of the scribe mark on the lining shall not exceed 1/16 inch.
Service (foot) Brake | Pleasure Vehicles | 30 feet |
Trucks and Buses | 40 feet | |
Parking (hand) Brake | All Vehicles | 80 feet |
(Thermoplastic nylon may have braid reinforcement or color difference between cover and inner tube. Exposure of second color is cause for rejection.)
Steering Wheel Diameter | Manual Steering System | Power Steering System |
16 inches | 2 inches | 41/2 inches |
18 inches | 21/4 inches | 43/4 inches |
20 inches | 21/2 inches | 51/4 inches |
22 inches | 23/4 inches | 53/4 inches |
Wheel Size: | 16 inches or less ............ | 1/4 inch (6.5mm) |
17 to 18 inches .............. | 3/8 inch (9.5mm) | |
Over 18 inches ............... | 1/2 inch (13mm) |
KINGPIN PLAY PROCEDURE: Relative to vehicles equipped with Kingpins. MVMA recommended procedures as noted in 540 CMR 4.05(13)(h)11. Be sure wheel bearing movement is eliminated by applying service brake during checking procedure.
Procedure: First eliminate all wheel bearing movement by applying service brake. With front end lifted, as illustrated for inspecting wheel bearings, grasp the tire at the top and bottom and attempt to move in and out to detect looseness. A pry bar may be necessary on heavy wheels.
Measure the movement at the top or bottom of the tire at the outer circumference.
Reject vehicle if measured movement at top or bottom of tire is greater than the distances described below:
Wheel size: | 16 inches or less ............ | 1/4 inch (6.5mm) |
17 to 18 inches .............. | 3/8 inch (9.5mm) | |
Over 18 inches .............. | 1/2 inch (13mm) |
540 CMR, § 4.05