A common practice is to remove the inspection plate on the bottom front of the transmission to expose the flexplate/flywheel, and use a heavy screwdriver or prybar in the teeth and against the block to stop the crank from moving.

Bolt, Harmonic Balancer Bolt, Chevrolet: 262-400, 7/16 x 20 thread, 13/16 in.

Yes, that bolt is normal thread, counterclockwise loosens it. The engine turns the opposite direction as the bolt removal direction to gaurantee that it won’t back out.

Yes, that bolt is normal thread, counterclockwise loosens it. The engine turns the opposite direction as the bolt removal direction to gaurantee that it won’t back out. Consequently, it’s ridiculously tight.

There is a way to do it. You put a wrench on the pulley bolt and block the other end against the floor or the frame. Then you use the starter motor to turn the engine (DO NOT START IT, JUST TURN IT) for at most one or two revolutions of the crank. Just enough to break the bolt loose.

You can also pry the threads out or remove them by slowly threading the bolt, depending on the crank arm type of your bicycle. Use a bolt or a spanner tool to remove and loosen the washers.

So, how long can you drive with a bad idler pulley? The safety recommendation is not to drive the car at all and take it to a mechanic immediately. You should be concerned if the vehicle makes squeaking or rattling noises.

It’s not okay to drive with a bad harmonic balancer. The bouncing crankshaft will wear on the main bearings. It can also tear up drive belts and possibly come apart posing a danger to people and property.

On certain engines, sometimes these last forever, last the life of the engine. And certain engines they might only last 50,000 miles or less than 10 years. This is a good example – because it’s got such a massive piece of rubber – you can see the rubber literally tears apart into two sections.

If the harmonic balancer gets too old or fails and can no longer properly absorb the harmonic vibrations, the engine will shake excessively. The shaking will become even more pronounced, and therefore dangerous to the engine at high speeds.

Cost of Harmonic Balancer Replacement On average for most vehicles, it can cost about $200 to replace a harmonic balancer. The cost of replacing the harmonic balancer varies mainly due to the type and model of the vehicle and the type and brand of parts used.