Auto Service Professional

JUN 2018

Magazine for the auto service professional

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Page 45 of 69

44 A S P J u n e 2 018 C h a s s i s S e r v i c e wrenches during wheel installations, and al- ways tighten to factory specifications, following the correct tightening sequence. Check brake rotors for lateral runout. Lateral runout causes the rotor to "wobble" as it rotates, kicking the brake pads in and out during brak- ing, resulting in pedal bounce. When checking lateral runout, the rotor must be secured to the hub with all wheel fasteners (not only two or three wheel nuts or bolts), with fasteners torqued to specification. Mount a dial indicator base to a solid and non-moving surface and lace the indicator plunger perpendicular to the rotor disc sur- face. Preload the plunger by about 0.050 inch and then zero the indicator gauge. Slowly ro- tate the rotor a full 360 degrees and observe the movement of the gauge needle. Compare your reading to factory specifications. Gener- ally speaking, lateral runout exceeding 0.0025 inch is too much and may require rotor replace- ment. However, before replacing an otherwise acceptable rotor, mark the orientation of the rotor to the hub (matchmark one wheel stud and its adjacent location relative to the rotor). Remove the rotor and re-position it to the hub in the next clock position and re-check for run- out. You may have a stack-up of runout toler- ance between the rotor and the hub. If you start to see an improvement, re-position the rotor Each transmitter accepts a plug-in clamp. The clamp is placed onto a surface at/ near the component being monitored. Transmitters feature a pair of internal magnets that aid in mounting to the vehicle. This wireless set of chassis ears includes the controller/receiver, four individual-channel sensor/ transmitters, clamps, Velcro straps, earphones and an initial supply of AA and AAA batteries.

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