Test Drives

Road testing a vehicle prior and post to a repair can be just as important as the repair itself. The BRAKE & FRONT END offices are located in a vast office park and I often see the techs from Wilson's Garage test driving through the roads of the office park.
When going for a test drive, a technician should have a clear objective and methodical plan for verifying the problem. It is also a chance to inspect the vehicle for other unperformed repairs.
The main goal of a test drive should be to verify the customer's problem, not a chance to go get coffee. One of the keys to becoming a good test driver is to find a driving "loop" or route that has a variety of road conditions.
Your test loop should consist of sections: a flat and straight section; an area to test braking and acceleration; an area with a dip or bump, and an area that offers both left and right turns.

Flat and Straight
On the flat and straight section of the loop, test directional instability and observe steering wheel position. Check for excessive steering wheel play. The vehicle may drift if the steering system is excessively loose.

Stop and Start
Use a parking lot or rarely used section of road for this section of the test. This test is used to detect brake pulls, torque steer and worn or loose suspension or steering components.
Check for a brake pull when stopping the vehicle. The owner may think this is an alignment-related problem.
Check for excessive nose-diving during braking. This is not normal and may be caused by worn springs or shocks. Worn springs will affect vehicle ride height and may affect overall vehicle handling.

Dips and Bumps
Drive the vehicle over the bump or through the dip and observe the steering wheel position. This is an excellent test to detect weak springs, weak shocks and worn or unlevel steering components.

Left and Right Turns
Check the overall handling response through both left and right turns. Front and rear alignment settings, as well as steering and suspension components, affect cornering capabilities. Check for steering difficulties that may be the result of mechanical binding or interference. Any excessive body sway could indicate worn springs, shocks or stabilizer assemblies. Look for any excessive squealing of tires during turns. This can be caused by incorrect alignment settings or turning angle out of spec.

Developing a methodical and consistent test drive loop and procedure can improve your chances of coming back from a test drive with a better understanding of the problem the owner is experiencing. Having a plan and a loop can eliminate distractions that could lead to an accident.