05-11-99 All Revised power brake booster check valve.
This bulletin applies to vehicles equipped with the 5. 9L Cummins diesel engine. A revised power brake booster check valve p/n 05011393AA has been released for service. The new check valve performance has been improved by changing the flapper style check valve to a spring loaded style check valve. The spring loaded style check valve performance is superior, especially in vehicles that utilize mechanical vacuum pumps to provide the vacuum source to operate the power brake booster. Part number 05011393AA should be used any time the power brake booster check valve is serviced on the subject model vehicles