Road Test

- Occasional brake squeal can be caused by environmental conditions such as cold ambient temperatures, heat, rain, snow, salt, mud, hot ambient temperatures, or high humidity. This occasional squeal is not a functional problem and does not indicate any loss in brake effectiveness.

- Visually examine the front and rear tires and wheel assemblies for damage such as uneven wear, tread washouts, or sidewall damage. Make sure the tires are of the same size, type and, where possible, same manufacturer.

- If tires exhibit uneven wear or feathering, the cause must be corrected. Check the steering and suspension components for damage/wear and, if necessary, check and adjust the steering alignment.

- Wheels and tires must be cleared of any foreign matter, and tire pressures must be adjusted to the correct specification.

- Use an established route for all brake diagnosis road tests. The route should be reasonably smooth and level. Gravel or bumpy roads are not suitable because the surface does not allow the tires to grip the road equally. Crowned roads should be avoided because of the large amount of weight shifted to the low set of wheels on this type of road.

- A key factor in evaluating brake concerns is the deceleration rate. This varies from vehicle to vehicle and with changes in operating conditions. It is evident how well the brakes on a particular vehicle are working after just a few applications.

- For this test, you need to mark out or find a driving lane that is 3.7m (12 ft) wide. You also need to place two markers along this lane, 7.5m (25 ft) apart. At a speed of 32 km/in (20 mph), drive down the center of the lane and apply the brakes at the first marker. Observe whether the vehicle comes to a smooth stop before the second marker. Also, note whether it pulled to the right or left and whether it went beyond the 3.7m (12 ft) width.