TABLE OF CONTENTS Accurate measurement plays an important part in vehicle maintenance and repair. For example, measurements that are routinely taken are:
valve clearances
steering angles and track alignment
exhaust emissions
compression pressures
alternator charging rate
tyre pressures
brake disc run out
brake disc thickness, brake pad thickness
shaft and bearing clearances.
Figure. 13.1 shows a number of examples of the types of measurements and the measuring instruments that are used in motor vehicle maintenance and repair work.
Feeler gauges are used in motor vehicle repair and maintenance for such purposes as checking valve clearances, piston ring gaps and many other clearances. The feeler gauges, shown in Fig. 13.2, are typical of the type that form a part of a technician's tool kit. They are made from high-grade steel that is tempered for hard wear and durability and the size of each blade is etched into the surface.
Figure. 13.1(a) shows a feeler gauge in use, measuring valve clearance. In this example, the feeler gauge is being inserted between the heel of the cam and the cam follower, with the valve in the fully closed position. When ready to proceed with the measurement, the gauges of the required thickness are inserted in the clearance between the heel of the cam and the cam follower and a light-hand force, sufficient to slide the feeler gauge...
