K 3500 Truck 4WD V8-379 6.2L DSL (1985)
Technical Service Bulletin # 883985
Date: 890301
Brakes - Front Calipers
Number:
88-398-5
Section:
5
Date:
MARCH, 1989
Subject:
FRONT BRAKE CALIPERS
Model and Year:
1984-86 C1, 2, 3 1986-87 R1, 2, 3 1984-88 G1, 2, 3
TO:
ALL CHEVROLET DEALERS
This bulletin cancels and supersedes Dealer Service Bulletin 88-391-5 and provides correct part numbers for the new brake calipers. All copies of
88-391-5 should be discarded.
New front brake calipers for the models listed above are now available from GMSPO. These new calipers have smoother bore finishes. If caliper
replacement is being considered to correct a braking induced directional lead (either right or left) the following inspections and procedures should be
performed.
Evaluation of a vehicle's brake performance is not intended to be made with the vehicle operator's hands removed from the steering wheel. Vehicles that
exhibit directional bias under these conditions are not considered to exhibit brake lead.
Before road testing the vehicle, perform the following services:
Preliminary Inspection
^
Inspect tires for excessive, uneven wear - replace if necessary.
^
Equalize tire pressures.
^
Equalize parking brake adjustment.
^
Adjust rear service brakes to .030" running clearance.
^
Check and if necessary, adjust the front end alignment, including toe.
^
Inspect caliper brake line bolt (# 34, page 5A8, Figure 4, 1988 Service Manual) for proper location of orifice. The orifice should be located in the
unthreaded part of the bolt. If the orifice is located in the threaded portion of the bolt then the the bolt must be replaced.
IMPORTANT:
After the preceding inspections and/or adjustments have been made, the vehicle should be road tested to verify if a lead still exists.
Vehicles that lead may lead either right or left when the brakes are applied.
Make all stops on a dry, level (no crown), clean roadway.
IMPORTANT:
Each applicable step must be thoroughly completed to effect a lasting repair. Failure to complete the procedure exactly as written
may result in an unsatisfactory repair.
Safely conduct a series of 5 stops from 55 mph bringing vehicle to a stop in 5 seconds (16 FPS Sq.). Record amount and direction of lead. Do not slide
or lock wheels.
*
FPS Sq. or Ft/Sec2 is the measurement used for calculating the deceleration rate with a decelerometer. Use of decelerometer, when available, is
the preferred method.
Procedure A
