C 3500 Truck 2WD V8-454 7.4L (1990)
Vacuum Brake Booster: Customer Interest
Brakes - Hard Pedal Feel
Number: 91-212-5
Section: 5
Date: February 1991
Corporate Bulletin No.: 065026R
Subject:
IMPROVED BRAKE PEDAL FEEL
Model and Year:
199O-91 K1 TRUCKS WITH JB3 BRAKES
Some customers may comment about hard brake pedal feel or reduced assist on some 1990-91 "K1" truck series equipped with JB3 brakes. A new larger
displacement brake vacuum booster will be installed in "K1" series production effective with VIN numbers listed below. The new booster is being
installed to improve power assist during braking and to improve the "feel" of the brakes, especially for customers who operate their vehicle heavily
loaded most of the time.
Customers with vehicles built with the old booster who operate vehicles heavily loaded may prefer the improved brake pedal feel of the new booster. If
so, the new brake booster can be installed on vehicles with this condition. When installing the new booster, follow the procedure in Light Duty C/K
Service Manuals, Section 5A.
VEHICLES INVOLVED
The smaller displacement booster can be identified by the lefters BM printed on a white tag on the booster. The new larger displacement booster has the
lefters HR printed on the tag.
VIN BREAKPOINTS
Fort Wayne
Chevrolet
1GCDK14Z3MZ168422
Oshawa
Not Involved
Pontiac East
Chevrolet
1GCEK14CXME159028
SERVICE PARTS INFORMATION
Part Number
Description
18012114
Brake Booster
Part is currently available from GMSPO.
WARRANTY INFORMATION
For vehicles repaired under warranty use:
Labor Operation:
H1220
Use applicable Labor Time Guide for labor hours.
