GM Full-Size Trucks 1980-1987 Repair Guide

Driven Disc and Pressure Plate

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REMOVAL & INSTALLATION



See Figure 1


CAUTION
The clutch driven disc contains asbestos, which has been determined to be a cancer causing agent. Never clean clutch surfaces with compressed air! Avoid inhaling any dust from any clutch surface! When cleaning clutch surfaces, use a commercially available brake cleaning fluid.



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Fig. Fig. 1: Lubrication points of the throwout bearing

Diaphragm Clutch

Before removing the bellhousing the engine must be supported. This can be done by placing a hydraulic jack, with a board on top, under the oil pan.

  1. Remove the transmission.
  2.  
  3. Disconnect the clutch fork pushrod and spring. Remove the clutch housing.
  4.  
  5. Remove the clutch fork by pressing it away from the ball mounting with a screwdriver until the fork snaps loose from the ball or remove the ball stud from the clutch housing. Remove the throwout bearing from the clutch fork.
  6.  
  7. Install a pilot tool (an old mainshaft makes a good pilot tool) to hold the clutch while you are removing it.
  8.  

Before removing the clutch from the flywheel, mark the flywheel, clutch cover and one pressure plate lug, so that these parts may be assembled in their same relative positions. They were balanced as an assembly.

  1. Loosen the clutch attaching bolts one turn at a time to prevent distortion of the clutch cover until the tension is released.
  2.  
  3. Remove the clutch pilot tool and the clutch from the vehicle.
  4.  

Check the pressure plate and flywheel for signs of wear, scoring, overheating, etc. If the clutch plate, flywheel, or pressure plate is oil-soaked, inspect the engine rear main seal and the transmission input shaft seal, and correct leakage as required. Replace any damaged parts.

To install:
  1. Install the pressure plate in the cover assembly, aligning the notch in the pressure plate with the notch in the cover flange. Install pressure plate retracting springs, lockwashers and drive strap to pressure plate bolts. Tighten to 11 ft. lbs. The clutch is now ready to be installed.
  2.  
  3. Turn the flywheel until the X mark is at the bottom.
  4.  
  5. Install the clutch disc, pressure plate and cover, using an old mainshaft as an aligning tool.
  6.  
  7. Turn the clutch until the X mark or painted white letter on the clutch cover aligns with the X mark on the flywheel.
  8.  
  9. Install the attaching bolts and tighten them a little at a time in a crossing pattern until the spring pressure is taken up.
  10.  
  11. Remove the aligning tool.
  12.  
  13. Pack the clutch ball fork seat with a small amount of high temperature grease and install a new retainer in the groove of the clutch fork.
  14.  


WARNING
Be careful not to use too much grease. Excessive amounts will get on the clutch fingers and cause clutch slippage.

  1. Install the retainer with the high side up and with the open end on the horizontal.
  2.  
  3. If the clutch fork ball was removed, reinstall it in the clutch housing and snap the clutch fork onto the ball.
  4.  
  5. Lubricate the inside of the throwout bearing collar and the throwout fork groove with a small amount of graphite grease.
  6.  
  7. Install the throwout bearing. Install the clutch housing.
  8.  
  9. Install the transmission.
  10.  
  11. Further installation is the reverse of removal. Adjust the clutch.
  12.  

Coil Spring Clutch

Basically, the same procedures apply to diaphragm clutch removal as to coil spring clutch removal.

  1. Before removing the clutch, punch-mark the flywheel, clutch cover and one pressure plate lug so that the components can be reassembled in their original locations.
  2.  
  3. Loosen the attaching screws one turn at a time to prevent distortion.
  4.  
  5. When the clutch plate is removed, be sure to mark the flywheel side.
  6.  
  7. Place 3 /8 in. wood or metal spacers between the clutch levers and the cover to hold the levers down as the holding screws are removed.
  8.  

 
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