Hydraulic Brake Booster Parts Restriction - keywords alarm chime hydraulic leak low pedal pressure warning

This PI is being superseded to update models. Please discard PIT4173.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Hydraulic Brake Booster Parts Restriction

Since the last restriction we have made some quality improvements and we want to verify the effectiveness of those improvements. Starting on November 6th, 2006 we will be putting the Brake Booster back on restriction for the following models GMT560 C-Series, Conventional Cab, GMC Topkick, Chevrolet Kodiak, GMT560 T/F- Series Tilt Cab, GMC F model, Chevrolet F-model.

We will be restricting both the Booster Brake and Brake Booster assembly. The Part Numbers are: 88935861, 88934860 and 88935862.

Prior to calling PQC or TAC please refer to a new PI #PIT4042 on the Bosch Hydro-Max Brake Booster Diagnostics.

Attached is a questionnaire that engineering needs to have filled out prior to contacting PQC at 1-866-654-7654. If you need Technical Assistance Please contact the Medium Duty Technical Assistance Center at 1-800-633-4863 / Prompt #3 (U.S. dealers only). Canadian dealers should contact the Medium Duty Truck group at Canada TAC, 1-800-263-7740 (English) or 1-800-263-7960 (French).

Your continued cooperation with these types of programs is helping all of us achieve our goal of being the Highest Quality Manufacturer of Motor Vehicles.

GMT 560 Brake Booster questionnaire

__ Number of times in for the same condition

__ Number of days vehicle in dealership for same condition

__ Y / N - Is the vehicle modified/non-production accessories (List below)

Customer Complaint:

___________________________________________________________________________

List DTC: _______________________________________________________________

SI Document ID# Used_____________________________________________________

Document each step of the trouble chart. (Include all DVM readings/comments):

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________________

Did you see the brake booster leaking? ____________

Did you clean the booster with soap and water? _______________________

What is the color of the fluid? ____________________________

Does the fluid dissolve in water? ______________________

If yes it is brake fluid and where is it leaking? ________________________

Is the fluid color red? _____________________________

If yes it is power steering fluid and where is it leaking? ___________________________________

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.