GM Bonneville/Eighty Eight/LeSabre 1986-1999

Camshaft/Balance Shaft Bearings

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REMOVAL & INSTALLATION



See Figure 1

Camshaft bearing removal should be done by a qualified machine shop because the tools needed are expensive and would not be economical to purchase for a one time usage. A machine shop can also line-bore the bearings after installation, to avoid premature camshaft and valve train wear.

Care must be exercised during bearing removal and installation, not to damage bearings that are not being replaced.

  1. Remove camshaft as outlined earlier in this section.
  2.  
  3. Assemble the puller screw to required length.
  4.  
  5. Select the proper size expanding collet and back-up nut.
  6.  
  7. Install the expanding collet on the expanding mandrel. Install the back-up nut.
  8.  
  9. Insert this assembly into the camshaft bearing to be removed. Tighten the back-up nut to expand the collet to fit the inside diameter of the bearing.
  10.  
  11. Thread the end of the puller screw assembly into the end of the expanding mandrel and collet assembly.
  12.  
  13. Install the pulling plate, thrust bearing, and pulling nut on the threaded end of the puller screw.
  14.  
  15. The bearing can then be removed by turning the pulling nut.
  16.  

Make certain to grip the5/8in. hex end of the puller screw with a wrench to keep it from rotating when the pulling nut is turned. Failure to do this will result in the locking up of all threads in the pulling assembly and possible over expansion of the collet.

  1. Repeat the above procedure to remove any other bearings, except the front bearing, which may be pulled from the rear of the engine.
  2.  

When removing rear cam bearing, it is necessary to remove the plug at the back of cam bore. However, if only the front bearing is being replaced, it is not necessary to remove the plug. The front bearing can be removed by using a spacer between the pulling plate and the cylinder block.

Click image to see an enlarged view

Fig. Fig. 1: Camshaft bearing replacement requires the use of several expensive tools

To install:
  1. Assemble the puller screw to required length.
  2.  
  3. Select the proper size expanding collet and back-up nut.
  4.  
  5. Install the expanding collet on expanding mandrel.
  6.  
  7. Install the back-up nut.
  8.  
  9. Place a new camshaft bearing on the collet and GENTLY hand tighten back-up nut to expand the collet to fit the bearing. Do not over tighten the back-up nut. A loose sliding fit between collet and bearing surface is adequate. This will provide just enough clearance to allow for the collapse which will occur when the new bearing is pulled into the engine block.
  10.  
  11. Slide mandrel assembly and bearing into bearing bore as far as it will go without force.
  12.  
  13. Thread the end of the puller screw onto the end of the mandrel. Make certain to align the oil holes in the bearing and block properly. One of the collet separation lines may be used as a reference point.
  14.  
  15. Install the pulling plate, thrust bearing and pulling nut on threaded end of puller screw.
  16.  
  17. Install bearing in the same manner as described in Steps 8 and 9 under Bearing Removal.
  18.  

When installing rear cam bearing, install a new plug at back of cam bore. Coat the outside diameter of the plug with non-hardening sealer before installation.

 
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