K 1500 Suburban 4WD V8-393 6.5L DSL Turbo VIN S (1996)
Brake Bleeding: Service and Repair
Hydraulic System Bleeding
Manual Bleeding
Gravity and vacuum bleeding procedures are not recommended for use with the anti-lock brake system. The two person (manual) bleed
procedure is the preferred method, although pressure bleeding is also possible. Do not pump the brake pedal during the bleeding process, as
fluid aeration may occur.
1. Raise and support vehicle, then connect a clear plastic tube to brake bleed screw at righthand rear wheel.
2. Place free end of tube in a glass jar partially filled with clean brake fluid.
Ensure end of tube remains submerged in fluid and master cylinder reservoir is kept full.
3. Open bleed screw 1/2-1 full turn, then slowly depress brake pedal until it reaches bottom of travel.
4. With pedal held down, tighten bleed screw, then release brake pedal and wait 10-15 seconds.
5. Continue bleeding wheel hydraulic circuit until approximately one pint of fluid has been bled through, or until air bubbles no longer flow out
through plastic tube.
6. Inspect master cylinder reservoir brake fluid level after every four to six brake pedal strokes.
7. Repeat preceding bleed steps for remaining wheel hydraulic circuits in the following order: first lefthand rear, then righthand front and, finally,
lefthand front wheel.
8. If any component is replaced which may have allowed air to enter Brake Pressure Modulator Valve (BPMV), proceed as follows:
a. Set parking brake, then connect scan tool to diagnostic connector.
b. With brake pedal firmly applied, run scan tool "Function Test."
c. Re-bleed all four wheel hydraulic circuits using bleed procedure in preceding steps.
9. Ensure brake pedal feels firm and all bleed screws are tightened securely prior to test driving vehicle. Re-bleed system as many times as necessary
to achieve proper operation.
Pressure Bleeding
Gravity and vacuum bleeding procedures are not recommended for use with the anti-lock brake system. The two person (manual) bleed
procedure is the preferred method, although pressure bleeding is also possible. Do not pump the brake pedal during the bleeding process, as
fluid aeration may occur.
1. Install pressure bleeder using equipment manufacturer's instructions.
2. On models equipped with metering portion of combination valve, remove combination valve dust caps and install valve depressing tool No.
J-39177, or equivalent, on valve end.
3. Bleed all four wheel hydraulic circuits. Bleed righthand rear wheel first, followed by lefthand rear, righthand front and, finally, lefthand front.
Leave bleed screws open until one pint of fluid has been bled out of each wheel.
4. After all wheel hydraulic circuits have been bled, remove combination valve clip, then connect scan tool to diagnostic connector.
5. With brake pedal firmly applied, run four scan tool "Functional Tests," then repeat preceding steps.
6. Ensure brake pedal feels firm; re-bleed wheels as many times as necessary to achieve proper pedal feel. It is likely that two to three quarts of brake
fluid will be necessary to complete a thorough bleed procedure.
General Information
The braking system can be bled manually or with pressure bleeding equipment. If bleeding manually, check fluid level frequently.
Brake fluid should never be reused. Before driving the vehicle, check brake operation to ensure a firm pedal has been obtained.
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. Always seal and wipe off brake fluid containers to prevent spills.
Manual
