I 1981 BRAKE SYSTEM USAGE CHART I I 1981 C TRUCK DIESEL ENGINE I VEHICLE SPECIFICATIONS BRAKE SYSTEM SPECIFICATIONS OPT HVY I BASE BRAKES DUTY BRAKES MODEL WHEEL REAR BRAKE MERCHAND BRAKE MERCHAND V NO BASE RPO RPO RPO RPO RPO I C10703 117 5 5200 SINGLE JD3 J50 JD5 J55 C10703 117 5 5600 SINGLE JD3 J50 JD5 J55 I C l070G 117 5 6000 SINGLE JD5 J55 I I C10903 131 5 5200 SINGLE JD3 J50 JD5 J55 C10903 131 5 5600 SINGLE JD3 J50 JD5 J55 C10903 131 5 6000 SINGLE JD5 J55 I I I GENERAL MOTORS SERVICE PARTS 0PERATION5 LT TRUCK 62A REV 2 87 BRAKE SYSTEM 13 4 000 GROUP