BRAKE MASTER CYLINDER QUICK TAKE-UP VALVE SQUEAK

VEHICLES AFFECTED: 1982 to 1984 'G' Series With Vacuum Booster 1981 to 1984 'B', 'D', and 'E' Series With Vacuum Boosters 1980 to 1984 'X' Series 1982 to 1984 'A' And 'J' Series

A new master cylinder quick-take-up valve went into production in the above-listed models in December 1983. This new valve eliminates a squeak or whistle-type noise which may occur at the time the brakes are applied. QTU Valve Service Kits which contain a new valve, retaining ring, instruction sheet, and two reservoir grommets, are available from WDDGM for installation as listed below:

Master Cylinder Quick Take-Up Valve Kit Part Number Model Usage --------------- ----------- 18011866 - 1982 to 1984 'G' Series with Vacuum Boosters - 1981 to 1984 'B', 'D', and 'E' Series with Vacuum Boosters

18011899 - 1980 to 1984 'X' Series

- 1982 to 1984 'A' and 'J' Series

This noise can be diagnosed with the use of a stethoscope-type of instrument at the master cylinder body boss which contains the QTU Valve.

Bleeding of the brake system is not required when the proceduce included with the kit is followed (Copy of procedure included with bulletin for your information).

INSTRUCTION SHEET

This procedure is to be used for limited replacement of the Quick-Take-Up valve module in 1980 - early 1984 master cylinders. The service procedures are to be performed with the Mdster cylinder installed on the vehicle.

NOTE:

The following service operations are to be performed with the master cylinder at no less than 15 DEG C (60 DEG F) to avoiddamage to the reservoir at removal.

1. Clean and remove reservoir cover.

2. With a clean syringe (previously used ony with brake fluid) discard all brake fluid in the reservoir.

3. Place shop cloth under master cylinder. Reinstall reservoir cover. Grasp the reservoir at the base and rock the reservoir side to side, while pulling up, to remove reservoir from the master cylinder body. Be careful to catch excess brake fluid to avoid paint damage.

4. Remove and discard reservoir attaching grommets.

5. Carefully depress the Quick-Take-Up valve retaining ring with a small screw driver and pry retaining ring out. Avoid gouging the aluminum master cylinder body or damaging the retaining ring groove. Remove and discard the retaining ring, retaining washer and QTU valve. Inspect and clean the master cylinder body at the QTU port.

6. Lubricate the new QTU valve with clean brake fluid and install per diagram.

7. Install the Tru-Arc retainer ring provided and press down all around to assure positive seating. (Washer must not be used.)

8. Install new reservoir grommets into master cylinder at both locations. Lubricate grommets with clean brake fluid to aid reservoir assembly.

9. Place reservoir in grommets, press down and rock reservoir into position. Remove cover and fill reservoir with approved DOT 3 brake fluid. Replace cover and check brakes for pedal travel and brake warning light.

10. Bleed master cylinder and brakes as required.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.