GMC 12510801 Arm Kit,Valve Rocker

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Firs remove the rocker arm covers by removing one rocker arm mounting nut at a time and then disconnecting rocker arms, nuts, and pivot balls. Keep each set of rocker arm components in separate plastic bags with labels. In case you just want to take out the pushrods, make sure that you loosen the rocker arm nuts and turn rocker arms for pushrod removal clearance. Pull the pushrods out and store them separately. Check all rocker arms for wearing, cracking or other damage particularly where valve stems come into contact with pushrods. Examine galls in each rocker arm pivot seat and faces of pivot ball for stress cracks or unusual wear patterns. Get rid of old or damaged rocker arms, replacing them with new ones while also fixing new pivot balls. The hole must be open at the end of each rocker arm next to the push rod. Push rods should be examined at their ends for fractures and excessive wear. Bend test each pushrod over glass plate. Apply lubricant to lower ends of all pushrods before reinstalling them at their original locations ensuring they bottom out in lifter socket. Grease the upper ends of valve stems as well as ends of the pushrods on lifter side. Grease also should be applied on ball pivots so as not to damage them before tightening the nuts which hold down the rocker arms, pivot balls and nuts (and ensuring that they engage properly). Finally install the rockers cover.

Remove the rocker arm cover from the cylinder head. From the front of the cylinder head, remove the nuts for the rocker arms. When only the pushrods are being removed, twist them to one side so that they can be lifted out. The nuts, rocker arms and pivot balls should be removed and stored in marked containers because they must be replaced in their original positions. Take out and store separately pushrods so that mix up on installation may not occur. If it is necessary to take out pushrod guides for any reason, ensure they are labeled for proper reinstallation into their initial positions. Examine each rocker arm especially where there has been contact with either a valve stem or a pushrod face; look for wear cracks or other damage. Ensure that this hole is clear on each end of all rocker arms receiving a push rod. Inspect every area where the rocker arm pivots for signs of galling, cracking, or wear. Whenever these rocker arms are worn or damaged you need to replace them with new ones as well as using new pivot balls too. The ends of these pushrods should also be checked for excessive wear or cracks too! You can test if they are bent by rolling them over a piece of glass plate one by one starting from one edge to another always ending at an opposite corner point than where you started off from earlier (try moving it randomly around). Lubricate bottom ends of push rods using clean engine oil/moly based lubricant before reinstalling them back their original positionings, don't leave any dryness Remember to make sure that every lifter socket houses its respective whole length Ideally moly-base grease is applied at both valve stems' ends and uppermost points of related pushrods prior to positioning all those rockers while fitting corresponding nuts after wards Position the arms onto place before putting back pivot balls plus nuts After engine oil pressure has built up apply moly-base grease to the pivot balls so as not to destroy the bearing surfaces and then tighten the nuts.

First, remove the valve cover from the cylinder head to inspect and take out rocker arms and pushrods. It is important to make sure that a specific cylinder is at Top Dead Center (TDC) and that the lifters for this cylinder are on base circle of camshaft when removing them. To show TDC, use a plastic pen through the spark plug hole to raise piston on its highest point by rotating the crankshaft. Loosen rocker arm bolts, take off rocker arm nuts, rocker arms and pivot balls ensuring they are carefully stored in marked containers. Rotate the rocker arms aside for an easy pushrod removal. Also, don't forget about the pushrod guides if necessary remove them marking them for proper reinstallation. Look for wear, cracks, or damage especially where they contact with pushrods and valve stems on rocker arms. Inspect the rocker arm pivot area for wear, cracks or galling and make sure that each rocker arm has an open pushrod-end hole. Replace damaged or worn out rocker arms with new pivot balls as required. Lubricate lower ends of pushrods with engine oil or moly-based grease before installing them into their original locations and checking that they sit properly in lifter socket. Apply moly-based grease on valve stem ends and upper pushrod ends before positioning you're your installing bolts for aileron activator. With care, install pivot balls and bolts then tighten rocker arm nuts while no valve spring load is present on it; replace retainer bolt hand-tight before torquing down to specified amounts using a torque wrench set at 14-15 lb-ft; replace retainer bolt hand-tight before torquing down to specified amounts using a torque wrench set at 14-15 lb-ft. In later models align tab on roller rocket pivot with slot in cylinder head casting protrusion; reinstall valve cover after tightening rocker arms then check for oil leaks or valve train noises after starting the engine.

Start removing the rocker arm stud nuts at the front of one cylinder head.

Check the rocker arm pivot area for wear, cracks, and galling.