The driver must be well aware of the operation of the braking system and the accepted general recommendations for operation. This will allow for a quality comparison and determination of the causes of the problem.
An experienced mechanic will always have a route that he will use for all road tests when diagnosing brake problems. The road chosen should be reasonably level and level. Gravel or bumpy roads are not suitable because the surface does not allow the tires to grip the road evenly. Convex roads are also not suitable because most of the weight is carried by the lower wheels. Once a route has been developed and consistently used, the road surface component can be isolated from the test results.
Before the road test, obtain a full description of the customer's problem or suspect conditions. Using this description, an experienced mechanic will be able to match possible causes to the symptoms of failure. Certain items can be considered sources of the problem, while others can be ruled out. More importantly, the customer's description will help identify dangerous conditions that should be checked or corrected before the road test. The description will also help the mechanic formulate a basic approach to the road test, i.e., narrowing the problem down to specific items, a certain vehicle speed, or a certain condition.
Begin your road test with a general brake test. Based on your problem description, test the brakes at various vehicle speeds, using both light and heavy pressure on the brake pedal.
If the problem becomes clear during this check, verify that it matches the description given by the customer prior to the road test. If the problem is not clear, attempt to reproduce the problem condition using the information provided in the description.
If the problem persists, refer to the Symptom Chart.
| Sign of malfunction | Possible reason | Action |
| Noise in the brakes | Go to PINPOINT TEST A | |
| Vibration when applying brakes | Go to PINPOINT TEST B | |
| Pulling under braking | Go to PINPOINT TEST C | |
| Feeling of "softness" of the pedal | Go to PINPOINT TEST D | |
| The pedal drops too quickly | Go to PINPOINT TEST E | |
| The pedal moves down too slowly | Go to PINPOINT TEST F | |
| Excessive force when pressing the brake pedal | Go to PINPOINT TEST G | |
| The brakes lock when the brake pedal is pressed lightly. | Go to PINPOINT TEST H | |
| Brake drag | Go to PINPOINT TEST I | |
| Increased/erratic brake pedal travel | Go to PINPOINT TEST J | |
| The red indicator light is always on | ||
| Slow or incomplete brake pedal return. | Go to PINPOINT TEST K |
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