The crankshaft pulley has the very important job of driving the serpentine belt -- or the standard accessory belts -- for the engine components. Some crankshafts perform double duty by serving as a harmonic balancer, which means they absorb and control the vibration or resonance of the engine rotation. The bolt holding the crankshaft pulley can be one of the most difficult bolts to remove, because the pulley must be immobilized somehow. The industrious auto repair person can use several different techniques and tricks to get this troublesome bolt loose.
Place the vehicle in park, or if the vehicle has a standard transmission, place it in first gear. Set the emergency brake. Use the floor jack to raise the vehicle high enough to place two jack stands under the front part of the frame near the front wheels.
Slide under the vehicle, and spray the crankshaft pulley bolt with penetrating oil. Let soak for several minutes. Use the largest socket and wrench (drive size) you have, and place the socket over the pulley bolt. Position the wrench handle so it will turn in a counterclockwise direction. Consult an owner's manual for the correct loosening direction of your pulley if in doubt about its loosening rotation. First try to loosen by hand, pulling hard on the wrench handle. If the engine actually turns over, which it sometimes will, wrap a rag tightly around the wrench handle and strike it with a short-handle sledge hammer. The hammer shock should break the bolt loose.
Slide under the vehicle with a large electric impact gun. Use a pneumatic impact gun if you have access to one. Remove any radiator cowl or shroud that might be in the way, by using the appropriate small sockets and wrench. Place the impact gun directly in line with the bolt and set it for counterclockwise removal. Pull the trigger and maintain a steady pressure on the gun. Keep the gun from vibrating loose or slipping off the bolt. The impact gun should work to remove the most stubborn bolt.
Remove the small inspection plate at the bottom of the transmission bell housing, if so equipped. You will see the teeth of the flywheel here. Have an assistant wedge a large screwdriver between the flywheel teeth and the bell housing edge. Attach a socket and wrench to the crankshaft pulley bolt. Face the handle of the wrench upwards, in such a way that you will have room to turn it counterclockwise. Slip a long section of hollow pipe over the wrench end. Turn it counterclockwise while your assistant holds the flywheel in place. Shove hard to loosen the bolt. Be extremely careful with this procedure, since damage to the flywheel teeth can result.
Determine if a pulley holder kit can be applied to your specific vehicle. If so, you can use one to immobilize the crankshaft pulley so you can remove the bolt. Install the holder device on your pulley according to directions. Some will have thin bars that go through pulley holes that will wedge against block, for example. Use the appropriate socket and wrench or impact gun to loosen the bolt.
Determine the rotation of your engine by temporarily turning the ignition key to the "start" position and then to the "off" position, very quickly. Position the socket and wrench onto the pulley and adjust the direction -- forward and reverse button -- of the wrench so that when the engine turns, it will use its own rotational power to break the bolt loose. You'll need to slip a section of pipe or a long breaker onto the socket and let it touch the floor or ground. Have your assistant flip the key to the start position (only momentarily). Since the pipe or bar has been immobilized, the engine torque should loosen the bolt. Do not continually crank the engine over. Just "bump" it quickly. This should loosen the most stubborn crankshaft pulley bolts.
