Brake Booster - Low or No Power Assist

90amcjeep02

Models

1989 B2 Body


Subject

Power Brake Pedal Feel


Index

BRAKES


Date

February 12, 1990


No.

05-51-90

P-350
(C05-08-9)
BODY CODE LEGEND

B2 - SUMMIT


SYMPTOM/CONDITION

To improve brake pedal feel, a brake booster and check valve have been released, which reduces pedal effort. This reduced pedal effort does NOT affect brake performance.

The check valve is no longer serviced with the booster assembly. It will now be serviced with the vacuum hose as an assembly.

This booster and check valve/vacuum hose assembly is NOT interchangeable with earlier systems unless they are replaced together as an assembly. For the B2 (Summit) the introduction date for the reduced pedal effort booster system was October, 1988.

PARTS REQUIRED
1.5L 1.6L
1 Brake Booster Assembly PN MB668505 PN MB668995
1 Check Valve/Vacuum Hose Assy. PN MB668220 PN MB668221


REPAIR PROCEDURE:

1. To test for proper operation of the check valve, disconnect vacuum hose from booster. Connect a hand vacuum pump to the hose and operate until gauge on pump reads 12" hg, observe gauge, if vacuum drops more than 1" hg in one minute, check valve is defective and check valve/vacuum hose assembly must be replaced.
2. If vacuum check valve functions properly in step 1, reconnect hose to booster.

NOTE: CARE SHOULD BE EXERCISED WHEN REINSTALLING THE VACUUM HOSE TO THE BOOSTER THAT THE CHECK VALVE DOES NOT INTERFERE WITH THE BOOSTER LINE.

3. Disconnect vacuum hose from intake manifold or surge tank. Connect a hand vacuum pump to the hose and attempt to apply a vacuum to the hose. No vacuum should be able to be retained. Reconnect vacuum hose to intake manifold or surge tank.

4. Verify proper system operation.


POLICY: Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No. 05-60-01-90 . . . . . . . . . . . . . .1.2 Hrs.
(Power Brake Pedal Feel)

05-60-01-60 . . . . . . . . . . . . . .0.7 Hrs.
(Air Conditioning Equipped)


FAILURE CODE: 63 - Low or No Assist