TM-9-2320-279-20-1

M977 SERIES, 8x8 HEAVY EXPANDED MOBILITY TACTICAL TRUCKS (HEMTT)

TECHNICAL MANUAL; MAINTENANCE INSTRUCTIONS; ORGANIZATIONAL MAINTENANCE, VOLUME 1 OF 3

TM-9-2320-279-20-1 - Page 262 of 985

TM 9-2320-279-20-1

Troubleshooting Malfunctions (Cent)

Table 2-9. Troubleshooting (Cent)

Malfunction

Test or Inspection

Corrective Action

DUAL AIR BRAKE SYSTEM (CONT)

5. PRESSURE DROPS OVER 25 PSI (172<kPa) AT GAGE WHEN BRAKES ARE APPLIED.

R

Step 1.

Check brake treadle valve for leaks.

Replace leaking treadle valve (para 11-10).

Step 2. Check for air leak at brake chambers.

If air is leaking from brake chamber, replace (para 11-8 or 11-9).

Step 3. Check for leaks at relay valve.

If air is leaking from relay valve, replace relay valve (para 11-12).

Step 4.

Check air lines for leaks.

Repair air lines (para 11-35).

5. SPRING BRAKES WILL NOT APPLY.

Step 1. Check brake adjustment.

Adjust brakes (para 11-7).

Step 2. Check for kinked or damaged air lines from parking brake valve in cab to spring brake.

Repair kinked or damaged air lines or connectors (para 11-35).

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