Condition # 3

Powermaster III unit has possible internal leakage as diagnosed by ABS warning light with codes 32, 56 or 35 being stored in controller (these codes result from pump cycling between brake applies or pump running continuously). The diagnostics below are meant to supplement vehicle Service Manual information.

CORRECTIVE ACTION STEPS:
Step # 1 - Confirm if internal leakage is present

A. Use J37118 gauge to monitor accumulator pressure if gauge is available.

B. Turn ignition on and allow pump to charge accumulator.

C. If pump does not shut off within 40 seconds, leave ignition on and go to Step # 2 below to determine source of leak. Leave ignition on if proceeding to Step D below.

NOTE:
If diagnosing without J37118 gauge, do not perform Step D, go to Step E below.

D. With ignition on, observe pressure reading after pump shuts off. The pressure should stabilize within 200 psi of the pressure at time of pump shut off. If pressure does not stabilize within 200 psi, leave ignition on and go to Step # 2 below.

E. If leakage is occurring, the pump will self cycle within 10 minutes of pump shutoff (with or without J37118 gauge).

Step # 2 - Determine source of leak

NOTE:
For Steps A through C below, leave ignition on and DO NOT APPLY BRAKES.





A. Remove reservoir cover and place a clear tube over booster return port 54 (Figure 2). If fluid rises in tube, there is leakage in the power piston assembly. Repair Powermaster III units with Power Piston Kit P/N 18017615 and Powermaster Repair Kit P/N 18017614.

B. Place a clear tube over pump inlet port 55 (Figure 2). If fluid rises in tube, the check valve (Figure 3) is leaking. Repair with Check Valve Assembly Kit P/N 18019383.

C. Place a clear tube over relief valve 9 (Figure 2). If fluid rises in tube, the relief valve is leaking. Repair with Relief Valve Assembly Kit P/N 18015129.

NOTE:
Service Manual instructions for Pump Run Time Too Long are complete except that it is now possible to repair booster return port 54 (Figure 2) leaks with Power Piston Assembly Kit P/N 18017615.

NOTE:
The instructions for Pump Off Time Too Short are correct but do not allow for leak checks without applying brakes and do not instruct to check leakage through the reservoir ports. It also does not specify the kits which are now available to service the unit.