On older vehicles with V8 engines and crank pulleys with harmonic balancers it was a pretty easy job getting your pulley off to get access to your timing chain or for whatever other reason you needed.
These pulleys were held on by 3 to 4 bolts that were tightened under 70 foot pounds of pressure. Even dealing with troublesome bolts would mean adding a pipe to your ratchet and giving it a mild yank.
Today’s engines specifically smaller 4 cylinder and many 6 cylinder engines use a single bolt to hold the crank pulley on.
They also Key the pulley to crank so it will not spin but because of the single bolt design many of these bolts are fastened at 140 pounds of Torque which makes them pretty much impossible to remove with hand tools.
There are a couple tricks that you can make use of to make the job a little easier.
First before you go removing everything else that is in the way of your timing belt cover work on the crank bolt.
Keep your accessory belts tight and they will help secure the crank while you use an air wrench to get the bolt out.
You will need a large air compressor 5HP with a large tank and heavy duty impact hammer. As big as you can get is best.
Sockets should be short length impact with thick walls. Do not use a deep socket or any extensions as they will work against you losing you torque as you try to get the bolt off.
If the bolt does not want to come out after a few minutes of cranking on it at full blast then you have a few options.
Try Tightening it
First try tightening the nut to see if you can break the mechanical weld that has formed in the threads. Yes this sounds a little crazy but all you want to do is move the bolt a few thousandths of an inch to get it free. Now try loosening it again.
That trick works well on rusted bolts that may or may not be under high torque and also on fasteners like your axle nuts that pick up a lot of heat from your breaks.
If that does not work you can try applying Heat to the bolt to hopefully change the position of the threads. In honesty though when you are heating a fastener to get it off the heated item should be the outside. Because you are heating the bolt head you are really just taking the same chance you took when you tried to tighten the bolt … trying to make it move very slightly to break the mechanical weld.
If all else fails you have 2 other options.
There are a number of different special tools that can be used to help get these bolts off.
The way they work is by inserting or fastening them to the crank pulley to allow them to keep the crank in position while you turn the bolt with a large breaker bar.
They do seem to work in many instances but they are expensive and they are a single use item. For this reason you may want to see if your local shop will rent you one for the day.
Your final way off
Since you haven’t taken your car apart up to now all you need to do is drive it down to your local shop and ask them to break the nut free for you and then put it back on tight enough to get home but not so tight you can’t get it back off.
If you do this make sure they put a little anti-seize on the threads that way you know it will come off when you get it home.
Every manufacturer and even each engine is a little different. It is important to ask a few people how your model is best delt with.
Honda crank pulley bolts are well known for being extremely difficult to remove and other then an Axle nut they are probably the worst job of dealing with a Honda.
Remember don’t take your accessory belts off until you have the crank bolt lose. You do not need to remove the crank pulley once the bolt is loose just leave the bolt in place until you have removed everything else.
When in doubt don’t freak out every mechanic will tell you they have had the same problem. Fortunately they probably also had someone next to them to clue them in and lend them a bigger impact wrench.
The YouRepair Store sells a full line of Mechanics Tools including special tools used for removing crank pulley bolts and other tough items.
For special tools search – crank pulley tool “and car make”