S10/T10 Blazer 2WD V6-262 4.3L VIN Z (1994)
Brake Bleeding: Service and Repair
General Information
BLEEDING BRAKE HYDRAULIC SYSTEM
Bleeding is necessary if air has entered the hydraulic brake system.
It may be necessary to bleed the system at all four wheels if a low fluid level allowed air to enter the system, or the brake pipes have been
disconnected at the master cylinder or combination valve. If a pipe is disconnected at one wheel, then only bleed that wheel.
The time required to bleed the hydraulic system when the master cylinder is removed can be reduced by bleeding the master cylinder before installing
it on the vehicle.
With Four Wheel Antilock Brake System
FOUR WHEEL ANTILOCK BRAKE BLEEDING
The 4WAL brake pressure modulator valve (BPMV) should be bled after replacement or if air is trapped in it. Bleeding should not be necessary if the
fluid is not contaminated or no air is in the BPMV. There are internal bleed valves on each side of the BPMV that open internal channels. Open the
internal bleed valves 1/4 to 1/2 turn before bleeding. Should the module need bleeding, it must be bled after the master cylinder and before the wheel
cylinders and calipers.
NOTICE: The ignition switch must be in the "OFF" position or false trouble codes could be set to memory.
Tools Required:
- J 39177 Combination Valve Pressure Bleeding Tool
- TK 00000 Tech-1 Scan Tool
- TK 02650 RWAL/4WAL Cartridge Kit or 3000003 Mass Storage Cartridge
- A modified J 35856 Combination Valve Pressure Bleeding Tool can be used in place of J 39177 provided that the dimple is removed from it first.
Important: Expect to use two quarts of brake fluid to thoroughly bleed the system.
Fig. 59 EHCU/BPMV Module Bleeding
1. Open the internal bleed valves on the sides of the BPMV 1/4 to 1/2 turn each (A).
2. Install J 39177 on the left high pressure accumulator bleed stem (C) of the BPMV.
3. Install J 39177 on the right high pressure accumulator bleed stem (C) of the BPMV.
