Condition # 4

External leakage or loss of fluid in reservoir reported.

CAUSE:





Leakage underneath and to the rear of the Powermaster III unit is likely to be caused by a leaking check valve (Figure 3) or pump end cover (Figure 3). An additional source of leaks is the seal at the rear of the master cylinder, causing leakage between the rear of the master cylinder body and the mounting bracket (Figure 3).

CORRECTIVE ACTION STEPS

NOTE:
Refer to Service Manual for Depressurization, checking fluid level and checking location of leaks. Once source of leakage is located, it is now possible to fix most leaks with kits.

Step # 1 - Determine source of leak

A. If leak is around head of check valve (Figure 3), replace check valve assembly with a new check valve assembly (P/N 18019383).

B. If pump end cover (Figure 3) is cracked or leaking, repair with End Cover Assembly Kit 18019965 (includes new check valve).

C. If leakage occurs at the back of Powermaster III unit at mounting bracket (Figure 3), repair with Powermaster Repair Kit P/N 18017614. (See pedal return corrective action elsewhere in this bulletin for proper application of this kit).





D. The kits are also available to repair external leaks: (see illustration)

REFERENCE





Parts A complete listing of all components available to repair Powermaster III units.

PART AVAILABILITY:
Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation: H2518-Use Applicable Labor Time

Add: 1.0 Hr. To Rebuild Unit