Chapter 3 Brake Tools, Shop Equipment, and Service Information 33 Copyright by Goodheart-Willcox Co., Inc. Shoe and Drum Gauges Th e shoe and drum gauge, Figure 3-13, is used to adjust the shoes before the drum is reinstalled. Th is reduces the need to adjust the shoes aft er the drum is installed. To use the gauge, set the outer adjuster pointers to the maximum diameter of the drum. Th en use the inner pointers to adjust the shoes. Dial Indicators Dial indicators are useful for checking for loose parts, and for out-of-round rotors. A dial indicator is shown in Figure 3-14. To check a rotor, mount the dial indicator on the rotor surface and set it to zero. Th en slowly turn the rotor. Th e indicator pointer will move as the rotor turns. If the pointer moves excessively, the rotor is warped. Pedal Effort Gauges Th e pedal eff ort gauge, Figure 3-15, is used to measure the amount of foot pressure needed to apply the brakes. Th e gauge is attached to the pedal, and the pedal is then pressed. Pedal pressure can be read directly on the gauge. Hydraulic Pressure Gauges Hydraulic pressure gauges are oft en needed to measure the pressure produced by the master cylinder, and to check for internal system restrictions and leaks. Pressure gauges are also needed when working on anti-lock brake systems. Since brake system pressures can exceed 2500 psi (17,258 kPa), brake pressure gauges must be capable of reading a mini- mum of 4000 psi (27,580 kPa). Figure 3-16 shows one type of hydraulic pressure gauge. Shoe and drum gauge Set to drum diameter here Find correct brake shoe diameter here Lock knob Ford Figure 3-13. One type of a brake drum and shoe gauge. Goodheart-Willcox Publisher Figure 3-14. A dial indicator being used to check for brake rotor warpage. Goodheart-Willcox Publisher Figure 3-15. An electronic pedal effort gauge accurately measures pressure needed to apply the brakes. Pressure gauge Flex hose Adapter Chrysler Figure 3-16. Hydraulic brake pressure gauge and adapter. Because of high pressures involved, safety glasses must be worn when this gauge is used.