Start by taking out the engine cylinder head cover to reach the valve springs and stem seals once the engine cylinder head is already on the block. The next stage is to take off the cap screws, bridge and pivot assemblies and
Rocker Arms to look at each valve spring. Hold the push rods, bridges, pivots and rocker arms in exactly the positions they were in before, then examine the springs and the retainer to check for any cracks or weaknesses. With the plug straight, quickly remove the adjacent spark plug(s) and put a 14 mm (1/2 inch) air hose adapter into the spark plug hole after that. Attach the hose to the stud and supply at least 621 kPa (90 psi) to the air pressure line to press the valves against their seats. For cars with air conditioning, place a flexible air adapter over the No.1 cylinder for servicing. Gently hit the retainer or tip with a rawhide hammer to make the lock come loose from the retainer and then remove the locks using Valve Spring Compressor Tool MD-998772A. When you have the valve spring and retainer removed, take out the valve stem oil seals, knowing that the ones for each valve are labeled INT and EXH to show if they are intake or exhaust. Check the valve stems, with their grooves in particular and use an Arkansas smooth stone to smoothen out any imperfections. Carefully fit the oil seal, as the sharp parts of the valve spring lock groove could damage it; then lightly push the valve seal over the valve stem and its guide boss, to make certain it is properly set. Place the valve spring and retainer and use the Valve Spring Compressor Tool MD-998772A to tighten the spring. Then, insert your valve locks. Let go of the spring, take out the tool and turn the spring back-and-forth so it seals well on the engine cylinder head. Remove air pressure, take out the air hose, remove the adapter and fit in the spark plug. Repeat all the earlier steps for each additional valve spring you have in stock. Then, add the push rods while centering the bottoms in the hydraulic valve tappet cap, before placing the rocker arms, pivots and bridge in their normal places. Make sure you alternate between tightening bridge cap screws so as not to damage the bridge and tighten them all to 28 Nm (21 ft. lbs.). After that, fix the engine cylinder head cover.