A SUMMARY OF NORTH AMERICAN UNIFORM VEHICLE

ROADSIDE INSPECTION CRITERIA FOR 1998

Commercial Vehicle Safety Alliance.

A vehicle or combination vehicle is out-of-service if 20% or more of its brakes have one of the following defects:

• With engine off, reservoir at no more than 90 to 100 psi (dump excess pressure) and then brakes fully applied, push rod stroke ¼ in. or more beyond adjustment limit;
• Counting as one defective brake, two brakes having a stroke less than ¼ in. beyond adjustment limit.

Note: A brake at its adjustment limit is not a violation.

• Clamp-type chamber adjustment limit:

Type 6: (4½ in. O.D.) = 1¼ in. stroke.

Type 9: (5¼ in. O.D.) = 1 3/8 in. stroke.

Type 12: (5 11/16 in. O.D.) = 1 3/8

Type 16: (6 3/8 in. O.D.) = 1¾ in. stroke.

Type 20: (6 25/32 in. O.D.) = 1¾ in. stroke.

Type 24: (7 7/32 in. O.D.) = 1¾ in. stroke.

Type 30: (8 3/32 in. O.D.) = 2 in. stroke.

Type 36: (9 in. O.D.) = 2¼ in. stroke.

• Long-stroke chamber adjustment limit:

Type 16: (6 3/8 in. O.D.) = 2 in. stroke.

Type 20: (6 25/32 in. O.D.) = 2 in. stroke.

Type 24: (below 3 in. max stroke) (7 7/32 in. O.D.) = 2 stroke.

Type 24: (3 in. max stroke version) (7 7/32 in. O.D.) = 2 ½ in. stroke.

Type 30: (clamp-type chamber) ) (8 3/32 in. O.D.) = 2 ½ in. stroke.

Source: School Bus Technician, September, 2000