GM 12577692 Rod Assembly, Valve Push

You can Select Your Vehicle to check if 12577692 fits your vehicle.

Eliminating the components should be done by first unclipping the cable from the negative terminal of a battery. Then, take off the valve cover(s) to start doing the change process as shown below; The 3 bolts of the rocker arm mounting will be loosened one by one beginning with the drivebelt end of one cylinder head without removing them all; then the rocker arms, pivot balls, and pedestals must be separated, taking careful to stock all the parts of the rocker arm individually in accurately identified plastic bags for correct refitting. The rocker arms have a pedestal mount which is secured by a metal sleeve; the parts are in more or less integrated in assembly where the bolt can be tapped out. Take out the pushrods and keep them separately using a perforated cardboard box since the intake and the exhaust pushrods may differ in size and in terms of their colour. Check rocker arms for signs of wear, cracks or damage; also check that the rollers slide smoothly, and that the holes in the pushrod ends are open. Inspect push rods for any cracks, etc., and to look for any bending try to roll them over a flat surface. For reassembly apply clean engine oil or moly-base grease to the lower ends of the pushrods and replace them on the engine block where they belong so that they snap firmly in the lifter socket. Suffice it to say that it is customary to apply moly-base grease before the engines are started on each valve stem and upper end of the pushrods, and apply clean engine oil to the pivot balls and bearing surfaces of each rocker arm prior to the oil pressure coming up. Install the rocker arms, the pivot balls; pedestals and bolts fasten them to the standard torque limit before ensuring the pushrods engage and the correct positioning of the projections on the pedestals. Last but not the least; fit back the valve covers, turn on the engine and look for any dripping of oil or any noises coming from under the valve cover.

Disconnect the cable from the negative terminal of the battery. Remove the valve cover(s). Beginning at the drivebelt end of one cylinder head, remove the rocker arm mounting bolts one at a time and detach the rocker arms, pivot balls, and pedestals. Store each set of rocker arm components separately in a marked plastic bag to ensure they're reinstalled in their original locations. The rocker arms have the pedestal mount captured on the rocker arm bolt by a metal sleeve inside, and the components can be separated if necessary by tapping the bolt out of the pedestal, but normally all components for a particular valve will stay as an assembly. Remove the pushrods and store them separately to avoid mixing them up during installation; a perforated cardboard box can be used for storage, noting the label indicating the front end of the engine. Intake and exhaust pushrods are different lengths, with intake pushrods approximately 5-3/4 inches long and exhausts 6.0 inches long, and they may also have color codes for easy identification. Inspect each rocker arm for wear, cracks, and other damage, especially where the pushrods and valve stems make contact, ensuring the rollers operate freely and that the hole at the pushrod end of each rocker arm is open. Inspect the pushrods for cracks and excessive wear at the ends, rolling each pushrod across a piece of plate glass to check for bending. Lubricate the lower end of each pushrod with clean engine oil or moly-base grease and install them in their original locations, ensuring each pushrod seats completely in the litter socket. Apply moly-base grease to the ends of the valve stems and the upper ends of the pushrods, and apply clean engine oil to the pivot balls and bearing surfaces of each rocker arm to prevent damage to the mating surfaces before engine oil pressure builds up. Install the rocker arms, pivot balls, pedestals, and bolts, tightening them to the specified torque while ensuring the pushrods engage properly in the rocker arms and that the projections on the bottom of the pedestals fit into the grooves on the head before tightening the bolts. Finally, install the valve covers, start and run the engine, and check for oil leaks and unusual sounds coming from the valve cover area.

Lubricate the lower end of each pushrod with clean engine oil or assembly lube.

Apply moly-base grease to the valve stems and upper ends of the pushrods, and use clean engine oil on the pivot balls and bearing surfaces of each rocker arm to prevent damage before oil pressure builds.

Loosen the rocker arm pivot bolts one at a time to remove the rocker arms and bolts, followed by the pivot support pedestal.