Master Cylinder Diagnosis for GMC Truck GMC P42 Commercial Chassis 1999
These tests will not find all master cylinder malfunctions.
If you cannot find the cause with these tests, refer to Brake System Diagnosis.
Visual Inspection
| • | Check for a cracked casting or brake fluid leaks around the master
cylinder. |
| | A leak will have at least one drop of fluid. A damp condition is normal. |
| • | Check the pedal linkage for binding and for incorrect pushrod
length. |
| | Disassemble the master cylinder if no brake pedal binding or improper
brake pedal travel is found. Refer to
Master Cylinder Overhaul
. |
| • | Check the master cylinder for swollen or elongated primary piston
seals. |
