G 20 Van V6-262 4.3L VIN Z (1993)
Technical Service Bulletin # 931985
Date: 930501
ABS - Brake Bleeding Procedure
Number: 93-198-5
Section: 5
Date: MAY 1993
Corporate Bulletin No.: 365003
ASE No.: A5
Subject:
REVISED 4WAL BRAKE SYSTEM BLEEDING PROCEDURE
Model and Year:
1990-93 M/L, S/T
1992-93 C/K
1993 G MODELS WITH 4WAL
SERVICE UPDATE
Bulletin Description
THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 91-74-5 DATED OCTOBER 1990 TO UPDATE THE
BLEED PROCEDURE AND TO ADD MODELS SINCE EQUIPPED WITH 4WAL BRAKE SYSTEMS. ALL COPIES OF 91-74-5 SHOULD BE
DISCARDED. THIS BULLETIN ALSO UPDATES INFORMATION IN 1993 M/L SERVICE MANUAL, 1993 S/T SERVICE MANUAL, 1993 C/K
SERVICE MANUAL, 1993 G SERVICE MANUAL, AND STG RWAL/4WAL 1988-1991 APPLICATIONS MANUAL 15005.05 (VERSIONS 2 TO
5). PLEASE PLACE A COPY OF THIS BULLETIN IN EACH MANUAL. THIS BULLETIN IS EQUIVALENT TO SERVICE MANUAL UPDATE
BULLETIN 93-12-5, DATED SEPT. 1992.
This 4WAL brake system bleed procedure is the most efficient bleed procedure to date.
The 4WAL Brake Pressure Modulator Valve (BPMV), formerly called Electro Hydraulic Control Unit (EHCU), should be bled after replacement or if
air is suspected to be trapped inside the unit. There are two conventional methods to use when bleeding the 4WAL BPMV: (1.) Pressure Bleeding or (2.)
Manual Bleeding.
IMPORTANT:
There are two internal bleed screws (brass colored), one on each side of the BPMV, that open internal channels. Open the internal bleed screws 1/4
to 1/2 turn before bleeding (figure 2). New 4WAL BPMV's are shipped with the internal bleed screws open, so first close the internal bleed screws
until snug, then open 1/4 to 1/2 turn.
NOTICE:
Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid
from contacting these areas. Clean any fluid that may drip onto wheel cylinders or calipers to prevent corrosion. Always re-seal and wipe off brake
fluid containers to prevent spills.
Tools Required
