V r BRAKES TP243 4 589 19741978 BRAKE CHARTS The fo owing charts list the 19744978 Light Duty Truck Brake Systems Thess charts rnust be used to determine the exact brake system on a particular vehicle To determine the correct brake system the following information must be known f Gross Vehicle Weight iGVW This is given on the identiEcation tag located on the driver side door pillar or on Step Vans attached to the inside face of the dash and toe panel 2 Model number 3 Wheelbase 4 H D Power Brakes HP0 J55 This is an option available on most vehicles When trucks are equipped with this option the brake system may be upgraded to the next higher rating Example from JB3 to JB5 Trucks equipped with this option can be identified by checking the Service Parts identification Sticker EXAMPLE V lf rhe truck had a C 10903 with 131 5 WR and 5400 GVVIC it would be equipped with JB3 brake system lf the truck was equipped with J55 H D Brakes it would have the JB5 brake system 1974 PICKUP BRAKE SYSTEM USAGE VEHICLE SPECIFICATIONS TYPE OF BRAKE SYSTEM OPTIDNALLY AVAILABLE MODEL REAR RPO J55 H D N0 W B GVWR WHEELS BASE POWER BRAKES 110903 13 L5 4900 Single JBI I3I 5 5300 Single JB3 JB5 I3I 5 5400 Single JB3 JB5 I3 L5 5000 Single JB5 Truok has H D brakes as std equipment No higher brake system available I Kr THE SPECIFICATIONS OF EACH BRAKE SYSTEM ARE LISTED BELOW I WAREHOUSIIIG AND DISTRIBUTION DIVISION OF GENERAL MOTORS CORPORATION LT TRUCK 5I REV 2 83 M c 4 000 GROUP