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Super Coupe Club of America > SC Literature > How to replace your crank bolt and harmonic balancer

by Wayne Ing

  1. Remove the upper radiator hose.

  2. Remove the radiator fan.

  3. Remove the crankshaft pulley. There are (4) 13mm bolts holding it to the balancer. Do not remove the belts yet since they will help stop the motor from turning.

  4. Remove the balancer upper and lower dust shield. There is one nut and the top, and one at the bottom (reached from underneath the car). The upper and lower shields just snap together. You may have to remove the water pump pulley to reach the upper nut. Use a screwdriver to jam the water pump bolts to the water pump center shaft to stop it from turning.

  5. Remove all (3) serpentine belts using a 18mm socket on the tensioner pulleys.

  6. Remove the crankshaft bolt (if applicable) using a 7/8" socket and extension.

  7. Remove the harmonic balancer using a harmonic balancer puller available at any auto parts store ($20). Use two of the crank pulley bolts with the puller. If the balancer is broken, you may have to drill into the remaining portion of the balancer and insert self tapping screws for the puller to grab it. The balancer is easy to drill since it's aluminum. Be sure not to damage the crankshaft threads when drilling or using the puller. You may also use wire wrapped around the back of the balancer to pull it. Be careful as this may damage the balancer.

  8. Remove the broken portion of the crank bolt remaining in the crankshaft nose. It won't be in there very tight, but you need to get a firm grip on it. This can be done in several ways. The most common is to drill a pilot hole into the centre of the remaining bolt and use and EZout screw extractor. It's a reverse tap which will grab the bolt while spinning it out backwards. The next option is to use a dremel tool and cut a slot into the remaining bolt and use a flathead screwdriver to spin it out. You can also use JB Weld and bond a nut to the broken portion of the bolt. Be sure not to get any weld on the crankshaft itself. After letting it dry for 16 hours, you can spin it out with a socket. You can also have a nut welded to the broken bolt, just tacking it on the inside of the nut to the bolt. Be sure not to damage the crankshaft threads in any way.

  9. Inspect the old harmonic balancer for wear. Be sure there are no cracks in the housing. Inspect the rubber isolator for wear. If any defects are found, replace it.

  10. Reinstall the crank pulley onto the harmonic balancer. The pulley only fits on one way since the holes are offset. Torque the 4 bolts to 25 lb/ft using a torque wrench. You can use Loctite on the threads if you wish. Be sure the pulley sits on the balancer hub properly, DO NOT force it and DO NOT use the bolts to draw it in. It if does not sit square with the balancer it will damage the aluminum hub and be off balance.

  11. Apply a small amount of RTV to the crankshaft keyway and neck. This will stop oil seepage. Reinstall the balancer onto the crankshaft being sure to line up the keyway. Use a piece of wood on the crank pulley to gently tap it onto the crankshaft nose.

  12. Reinstall a NEW crankshaft bolt with washer, and apply a small amount of Loctite to the threads. DO NOT reuse the old crank bolt as they are prone to breakage. Torque the crankshaft bolt to 100 ft/lb. You can stop the motor from spinning in 5 speed cars by placing the transmission in gear and having someone step on the brakes. For automatic cars, you must jam the flexplate. Use the socket to jam one of the torque convertor bolts against the transmission housing or just get someone to hold it with a screwdriver.

  13. Reinstall the dust cover, water pump pulley, accessory belts, radiator fan, and upper radiator hose. Be sure to top up the coolant.

  14. Stand clear when starting the motor. Check that the crank pulley does not have any excessive vibrations. Check for oil and coolant leaks.

    Shown below is a picture of the harmonic balancer puller about to remove it from the crankshaft.

    Click on image to see larger version.

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Document Last Modified: 07/29/04 03:33 AM
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