chap97 pps Automotive technology at University of Cambridge

start Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 97, the reader should be able to: • • • • Prepare for ASE Suspension and Steering (A4) certification test content area “C” (Related Suspension and Steering Service) Explain how to perform a U-joint inspection List the steps necessary to replace a U-joint Explain how to perform a measurement of the working angles of a U-joint Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 97, the reader should be able to: • • Describe the service procedures for replacing CV joints and boots Describe the routine maintenance service procedures required for drive axle shafts and universal CV joints Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 KEY TERMS: Inclinometer pin bushings • pinch bolt spline bind • synthetic retainers torque prevailing nut U-joints Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The driveshaft of a typical rear-wheel-drive (RWD) vehicle rotates about three times faster than the wheels This is due to the gear reduction that occurs in the differential The driveshaft rotates at the same speed as the engine if the transmission ratio is to (1:1) The engine speed, in revolutions per minute (RPM), is transmitted through the transmission at the same speed Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The Squeaking Pickup Truck - Part The owner of a pickup truck complained that a squeaking noise occurred while driving in reverse The “eeeee-eeeee-eeee” sound increased in frequency as the truck increased in speed, yet the noise did not occur when driving forward Because there was no apparent looseness in the U-joints, the service technician at first thought that the problem was inside either the transmission or the rear end When the driveshaft was removed to further investigate the problem, it became obvious where the noise was coming from The U-joint needle bearing had worn the cross-shaft bearing surface of the U-joint The noise occurred only in reverse because the wear had occurred in the forward direction, and therefore only when the torque was applied in the opposite direction did the needle bearing become bound up and start to make noise A replacement U-joint solved the squeaking noise in reverse Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The Squeaking Pickup Truck - Part Figure 97–1 Notice how the needle bearings have worn grooves into the bearing surface of the U-joint Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 DRIVESHAFT AND U-JOINT INSPECTION The driveshaft should be inspected for the following: Any dents or creases caused by incorrect hoisting of the vehicle or by road debris Undercoating, grease, or dirt buildup on the driveshaft can cause a vibration Undercoating should be removed using a suitable solvent and a rag Always dispose of used rags properly CAUTION: A dented or creased driveshaft can collapse, especially when the vehicle is under load This collapse of the driveshaft can cause severe damage to the vehicle and may cause an accident Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The U-joints should be inspected every time the vehicle chassis is lubricated, or four times a year Original equipment (OE) U-joints are permanently lubricated and have no provision for greasing If there is a grease fitting, the U-joint should be lubricated by applying grease with a grease gun See Figure 97–3 Figure 97–2 All U-joints and spline collars equipped with a grease fitting should be greased four times a year as part of a regular lubrication service Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–3 Many U-joints require a special grease gun tool to reach the grease fittings Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman Continued ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Step #4 Use a prybar or special tool with a slide hammer, as shown below, and remove the inner joint from the transaxle Step #5 Disassemble, clean, and inspect all components See Figures 97–24 through 97–30 Figure 97–23 Most inner CV joints can be separated from the transaxle with a prybar Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman Continued ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–24 When removing a drive axle shaft assembly, use care to avoid pulling the plunge joint apart Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–25 If other service work requires that just one end of the drive axle shaft be disconnected from the vehicle, be sure that the free end is supported to prevent damage to the protective boots or allowing the joint to separate The method shown using a shop cloth to tie up one end may not be very pretty, but at least the technician took precautions to support the end of the shaft while removing the transaxle to replace a clutch Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–26 With a scribe, mark the location of the boots before removal The replacement boots must be in the same location Figure 97–27 Most CV joints use a snap ring to retain the joint on the drive axle shaft Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–28 After releasing the snap ring, most CV joints can be tapped off the shaft using a brass or shot-filled plastic (deadblow) hammer Figure 97–29 Typical outer CV joint after removing the boot and the joint from the drive axle shaft This joint was removed from the vehicle because a torn boot was found After disassembly and cleaning, this joint was found to be OK and was put back into service Even though the grease looks terrible, there was enough grease in the joint to provide enough lubrication to prevent any wear from occurring Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 97–30 The cage of this Rzeppa-type CV joint is rotated so that one ball at a time can be removed Some joints require that the tech use a brass punch and a hammer to move the cage Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Step #6 Replace the entire joint if there are any worn parts Pack all the grease that is supplied into the assembly or joint Assemble the joint and position the boot in the same location as marked Before clamping the last seal on the boot, be sure to release trapped air to prevent the boot from expanding when heated and collapsing when cold Figure 97–31 Be sure to use all of the grease supplied with the replacement joint or boot kit Use only the grease supplied and not use substitute grease This is sometimes called burping the boot Clamp the boot to manufacturer’s specs Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman Continued ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Step #7 Reinstall the drive axle shaft in the reverse order of removal, and torque the drive axle nut to factory specs Figure 97–32 A screwdriver is shown, but a punch would be better, to keep the rotor from rotating while removing or installing the drive axle shaft spindle nut Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The Vibrating Buick The owner of a front-wheel-drive Buick complained that it vibrated during acceleration only The vehicle would also pull toward one side during acceleration An inspection discovered a worn (cracked) engine mount After replacing the mount, the CV joint angles were restored and both the vibration and the pulling to one side during acceleration were solved Figure 97–33 The engine had to be raised higher to get the new (noncollapsed) engine mount installed Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Spline Bind Cure - Part Driveline “clunk” often occurs in rear-wheel-drive vehicles when shifting -between drive and reverse or when accelerating from a stop Often the cause of this noise is excessive clearance between the teeth of the ring and pinion in the differential Another cause is called spline bind, where the changing rear pinion angle creates a binding in the spline when the rear springs change in height When a pickup truck stops, the weight transfers toward the front and unloads the rear springs The front of the differential noses downward and forward as the rear springs unload When the driver accelerates forward, the rear of the truck squats downward, causing the drive shaft to be pulled rearward when the front of the differential rotates upward This upward movement on the spline often causes the spline to bind and make a loud clunk when the bind is finally released Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Spline Bind Cure - Part The method recommended by vehicle manufacturers to eliminate this noise is to follow these steps: Remove the driveshaft Clean the splines on both the driveshaft yoke and the transmission output shaft Remove any burrs on the splines with a small metal file (remove all filings) Apply a high-temperature grease to the spline teeth of the yoke Apply grease to each spline, but not fill the splines Synthetic chassis grease is preferred because of its high temperature resistance Reinstall the driveshaft Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 PHOTO SEQUENCE Drive Axle Shaft Replacement Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 PHOTO SEQUENCE Drive Axle Shaft Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman (cont.) ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY A defective U-joint often makes a clicking sound when the vehicle is driven in reverse Severely defective U-joints can cause driveline vibrations or a clunk sound when the transmission is shifted from Reverse to Drive or from Drive to Reverse Incorrect driveshaft working angles can result from collapsed engine or transmission mounts Driveline clunk noise can often be corrected by applying high temperature chassis grease to the splines of the front yoke on the driveshaft CV joints require careful cleaning, inspection, and lubrication with specific CV joint grease Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 end Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 ... falling off Figure 97–10 Taping the U-joint to prevent thefall caps comingalloff If the caps off from the U-joint, of the needle bearings will fall out and scatter over the floor Automotive Technology: ... cage of this Rzeppa-type CV joint is rotated so that one ball at a time can be removed Some joints require that the tech use a brass punch and a hammer to move the cage Continued Automotive Technology: ... original location of Ujoints before disassembly Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc