GM Service Manual Online
For 1990-2009 cars only

Series

System

Rear Brakes

Brake Assist

1500 (6100/7100 GVW) 2500 (7300 GVW)

JB6

11.15 x 2.75

Vacuum

2500 (8600 GVW)

JD7

Gas 13.00 x 2.50

Diesel 13.00 x 3.50

Hydraulic

3500 Single Wheel

JB8

13.00 x 3.50

Hydraulic

3500 Dual Wheel

JB8

13.00 x 3.50

Hydraulic