Knowing the terms helps you ask better questions. You do not need to own every tool, but you should understand what a workshop is measuring and why.
Fastening and torque
A torque wrench measures rotational force. A torque specification is only meaningful with clean threads and the specified lubrication. A torque angle gauge is used for fasteners that are tightened past the elastic range.
A thread pitch gauge identifies the thread; a tap and die clean or cut threads. Cross-threading is a repair, not a technique.
Measurement
Feeler gauges measure gaps, such as valve clearance. Vernier calipers measure outside and inside dimensions. Micrometers measure precisely with a screw. A bore gauge measures cylinder diameter.
Runout describes how far a rotating part deviates from true. Backlash is the play between gear teeth. End float is axial play.
Diagnosis
A compression gauge measures cylinder pressure. A leak-down tester measures where pressure escapes. A multimeter measures voltage, resistance and current. A vacuum gauge shows intake depression.
A scan tool reads fault codes and live data. It is a clue, not a diagnosis.
Chassis
A straight edge, laser or alignment fixture checks alignment. A spring compressor is used for suspension work. A bearing puller removes bearings without damaging the housing.
A tyre balance stand and a bead breaker are tyre tools. A torque wrench is still needed for the axle.
Checklist
- Torque and angle specifications.
- Feeler gauge for valve clearance.
- Calipers and micrometers for wear.
- Compression and leak-down tests.
- Multimeter for electrical faults.
- Runout and backlash measurement.
- Alignment and bearing tools.
Questions
Do I need all these tools?
No. Most owners need a basic set plus a torque wrench, gauge and multimeter. Specialised tools can be hired or left to a workshop.
What is leak-down testing?
It measures where compressed air escapes from a cylinder: rings, valves or head gasket. It is more specific than a compression test.
What is runout?
The deviation of a rotating part from true. A warped brake disc has runout.
