Document NGENrwBY19zo13O7r3Znq2wZE

R-120 3 & disc brake rotors. Rev dynamometer test procedures vere developed to efficiently perform these tests. The candidate linings were burnished, then applied 100 times at each of a sequence of rotor temperatures. The friction, vear, squeal, roughness and groan properties of the linings were recorded for each test condition and the overall cast iron vear of the rotor vas measured. Rotors vlth two different rubbing surface vail thicknesses and three different fin configurations were tested to determine cooling rate and effect upon lining wear rate for a prescribed stopping sequence. At the request of the Advanced Chassis Department, the friction and vear behavior of a nev prototype disc brake pad formulation (Bendlx D-7131X) has been examined on the FAST machine. The material is essentially an iron vire-graphite composite held together vith about 10 of a resin binder. The material exhibits fairly good friction and wear behavior; bovever, there is a slight increase in the coefficient of friction vith temperature which could result in brake temperature Imbalance. The material showed a tendency toward brake squeal at rotor temperatures above 500*F. The friction level is lav at ambient temperatures with high humidity, so the parking brakes may develop Inadequate holding capability and high pedal efforts on the first fev brake applications may be experienced. B. Disc Brake Roughness Car Engineering requested assistance in solving a disc brake roughness condition exhibited by the Initial production of 1972 Thundethirds. Of the two lining suppliers, Delco 5^90 provided definitely greater roughness although some roughness vas found vith the Bendlx 7133 linings. Rotors and linings from Vlxom tests were evaluated on cur brake dynamometer. Delco linings produced about 6o greater torque fluctuations than Bendlx linings. This roughness became significant above 500*F rotor temperature and vith repeated use produced some rotor coating. COATES V F-jr? T '5 PRODUCED BY FORD IN GQESIiai iI j . . i i i