Mazda Trucks 1972-1986 Repair Guide

Driveshaft and U-Joints

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REMOVAL & INSTALLATION



See Figures 1 through 7

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Fig. Fig. 1: 1972-76 driveshaft components



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Fig. Fig. 2: 1977-83 driveshaft components



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Fig. Fig. 3: 1984 driveshaft components



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Fig. Fig. 4: 1986 short bed driveshaft components



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Fig. Fig. 5: 1986 long bed driveshaft components



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Fig. Fig. 6: Matchmarking the rear flange and yoke



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Fig. Fig. 7: Matchmarking the yoke and shaft

  1. Matchmark the rear U-joint with the rear companion flange. Remove the bolts attaching the driveshaft to the rear companion flange.
  2.  
  3. On 2-piece units, remove the center support bearing bracket from the underbody.
  4.  
  5. Pull the driveshaft rearward and out of the transmission. Plug the rear seal opening.
  6.  
  7. Installation is the reverse of removal. Make sure that you align the matchmarks. Torque the rear companion flange bolts to 39-47 ft. lbs.; the center bearing bracket nuts to 27-38 ft. lbs.
  8.  

U-JOINT REPLACEMENT



See Figure 8

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Fig. Fig. 8: Exploded view of a U-joint

  1. Remove the driveshaft.
  2.  
  3. If the front yoke is to be disassembled, matchmark the driveshaft and sliding splined yoke (transmission yoke) so that driveline balance is preserved upon reassembly. Remove the snaprings which retain the bearing caps.
  4.  
  5. Select two sockets, one small enough to pass through the yoke holes for the bearing caps, the other large enough to receive the bearing cap.
  6.  
  7. Using a vise or a press, position the small and large sockets on either side of the U-joint. Press in on the smaller socket so that it presses the opposite bearing cap out of the yoke and into the larger socket. If the cap does not come all the way out, grasp it with a pair of pliers and work it out.
  8.  
  9. Reverse the position of the sockets so that the smaller socket presses on the cross. Press the other bearing cap out of the yoke.
  10.  
  11. Repeat the procedure on the other bearings.
  12.  
  13. To install, grease the bearing caps and needles thoroughly if they are not pregreased. Start a new bearing cap into one side of the yoke. Position the cross in the yoke.
  14.  
  15. Select two sockets small enough to pass through the yoke holes. Put the sockets against the cross and the cap, and press the bearing cap 1 / 4 in. below the surface of the yoke. If there is a sudden increase in the force needed to press the cap into place, or if the cross starts to bind, the bearings are cocked. They must be removed and restarted in the yoke. Failure to do so will greatly reduce the life of the bearing.
  16.  
  17. Install a new snapring.
  18.  
  19. Start a new bearing into the opposite side. Place a socket on it and press in until the opposite bearing contacts the snapring.
  20.  
  21. Install a new snapring. It may be necessary to grind the facing surface of the snapring slightly to permit easier installation.
  22.  
  23. Install the other bearings in the same manner.
  24.  
  25. Check the joint for free movement. If binding exists, smack the yoke ears with a brass or plastic faced hammer to seat the bearing needles. Do not strike the bearings, and support the shaft firmly. Do not install the driveshaft until free movement exists at all joints.
  26.  
  27. The nut attaching the yoke and bearing to the front coupling is torqued to 115-130 ft. lbs.
  28.  

 
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