GMC T Series 1994 Repair Manual page 482

3. Coat lower end (press-fit area) of stud with hypoid
axle lubricant. Drive the stud into place with a ham­
mer and J 6880. Stud is installed to proper depth
when the tool bottoms on the cylinder head (figure
58).
ASSEMBLY (5.0L AND 5.7L ENGINES)
Assemble (Figures 53 and 59)
*
Tools Required:
J 8062 Valve Spring Compressor
J 23738-A Valve Seal Leak Detector
1. Valves (258 and 259).
• Lubricate the valve stems with engine oil.
• Insert the valves into the proper guides.
2. Seals (257). Install the seals over the valve stems
and seat them against the head.
3. Springs with dampers (256).
4. Shields (255).
5. Caps (253) (intake valves only).
6
. Rotators (254) (intake and exhaust valves on 5.7L
H.D.and exhaust valve only on 5.0L and 5.7L
engines).
• Compress the valve spring, using J 8062 (figure
55). Compress the spring enough so the lower
valve stem groove can be clearly seen.
7. O-ring seals (252) and valve keepers (251).
A. Push a new O-ring seal onto the valve stem.
The seal must be installed on the stem's lower
groove. Make sure the seal is flat and not twist­
ed.
B. Apply a small amount of grease to the area of
the upper valve stem groove. Assemble the two
valve keepers using the grease to hold the keys
in place. Make sure the keepers seat properly
in the groove.
C. Release the compressor tool. Make sure the
valve keepers stay in place.
D. Repeat the preceding steps on the remaining
valves.
Figure 58— Installing the Rocker Arm Stud (5.0L
and 5.7L Engines)
Engines)
E. Check each seal, using J 23738-A (figure 59).
Place the adapter cup over the shield. Operate
the vacuum pump. Observe the vacuum pump
gage. No air should be able to leak past the
seal. If the seal will not hold a vacuum, it may
have been damaged or improperly installed.