Patent ID: 8342076

Claim:
A pneumatic brake actuator for a vehicle braking system comprising: a flange case; a cover cooperable with said flange case defining a head assembly therebetween, said head assembly forming a lower pneumatic chamber and an upper spring chamber; a power spring disposed inside said upper spring chamber, said power spring including terminal ends disposed radially inwardly from a peripheral edge of said power spring; a piston assembly disposed in said head assembly, said piston assembly moved in a first direction by said power spring and in a second direction when said lower pneumatic chamber is pressurized thereby compressing said power spring; and a spring guide disposed between said cover and said piston assembly disposed in said upper spring chamber, said spring guide being configured to receive said spring and extending radially outwardly toward said peripheral edge of said spring when said spring is in a compressed position thereby preventing said power spring from contacting said cover in either a compressed or decompressed position preventing a galvanic cell from forming between said spring, said head, and said spring guide when said spring is disposed in either a compressed or decompressed condition.