GMC 1989 Light Duty Truck, Repair Manual, Page: 100 / 998

1B5-6 SD-709 AIR CONDITIONING COMPRESSOR
3.
Tighten
• Nut the 36 N-m (27 ft. lbs.).
• Check the air gap with a feeler gauge. It should
be 0.49 to 0.79 mm (0.016 to 0.031 inch), if the
gap is not consistent all around, pry up slightly
at points of m inimum variation. Lightly tap down
at points of m axim um variation. The gap is
determ ined by the shims. If necessary, add to or
remove shims from the shim stack.
DISASSEMBLY OF THE
CYLINDER HEAD AND
VALVE PLATE
Remove or Disconnect (Figures 2 and 16)
Six cylinder head cap screws with a 13 mm wrench.
Cylinder head from the valve plate.
• Use a small hammer and the gasket scraper to
tap the outer edge of the head until it is freed
from the plate (figure 16).
• Check the gasket for wear.
Valve plate.
Position the gasket scraper between the outside edge
of the valve plate and the cylinder block and lightly tap
the valve plate loose.
Inspect the reed valves and d isch arg e retainer.
Replace if worn.
Gasket material carefully from the valve plate and
cylinder head with the gasket scraper.
ASSEMBLY OF THE
CYLINDER HEAD AND
VALVE PLATE
Important
Use new gaskets for reassembly.
Install or Connect (Figures 2 and 17)
1. Clean refrigerant oil to the valve plate gasket (17).
2. Gasket to the locating pin holes and oil orifice in the
cylinder block.
3. Valve plate (18).
• Align the valve plate locating pins to the pin
holes in the block.