I remember when I wanted to change the dust covers on my axle, what a pain it was to break free the axle nut with my breaker bar. I have only standard hand tools.

I can only imagine that loosening the crankshaft pully bolt will be just as hard, but the question is how do I keep the engine from turning while I'm doing this?

I've heard a few suggestions, like blipping the starter after disabling the fuel pump, or stuffing rope down one of the cylinders. I would also think you could just place a bar through the camshaft sprockets, or just put the car in gear with at least one wheel still on the ground?

Could someone detail the different methods, how to set them up, and any risks involved in each one? On the 98 Mazda 626 the Haynes manual says normal crank rotation is clockwise.

POSTSCRIPT Nov. 10th 2016

So I used the started to break the crank pulley bolt free, and I took @Paulster2's suggestion for tightening it back up when putting everything back together:

enter image description here

You need a decent quality vise grip. At first it was slipping, so I used an allen wrench to tighten it down till it held. I'm obviously going to have to replace this belt at some point soon. I did something similar to tighten down my water pump pulley bolts.

  • Manuel or automatic?
    – dlu
    Commented Oct 9, 2016 at 4:53
  • @dlu it's an automatic and I just realized it won't work because the torque converter doesn't give you a direct connection to the wheels. Commented Oct 9, 2016 at 7:05

3 Answers 3


I'd written the same answer for another post, but it had to do with taking the fan loose from the water pump where there is a single large nut on the fan connecting it. The same graphic will work here, but I'll describe what's going on to help you get control of the crank shaft bolt.

enter image description here

Obviously, the diagram is not your engine (or at least I assume it's not :o). The diagram depicts using an old serpentine belt and two pairs of Vise-Grips. Wrap the serpentine belt around the crankshaft pulley (harmonic balancer) and clamp it with the first set of Vise-Grips online with the second pulley you're going to use. Then wrap the belt around the second pulley (in this case the A/C pulley), clamping the second set of Vise-Grips opposite the crank pulley. You'll find by doing this, the belt will have more than enough traction (as long as it's not completely worn out) to hold the crank in place while you either break the crank pulley bolt free or even torque it back into place. This method is far safer than using the starter to break it free and also allows you to do the procedure in reverse.

NOTE: Don't use a good belt to do this or a belt you plan on reusing. It will degrade the integrity of the belt.

As an anecdote about the how well a serpentine belt will hold, I had an 91 Suburban with 350-V8 in it. These are fairly strong running engine with plenty of torque. I was travelling about 35 mph when the alternator froze up. Through the serpentine belt, there was enough grip through the pulleys to stop the engine. This caused no damage to the engine and once I replaced the alternator, everything was fine. Just stating if the belt has enough grip through the alternator pulley to do this, it will have more than enough gripping power as I've described to hold the crank still while you break lose the hub bolt.

  • That looks complicated. Commented Oct 9, 2016 at 17:54
  • @RobertS.Barnes - It's actually VERY simple. Commented Oct 9, 2016 at 18:35
  • Then I must be very tired... I'll think about it again tomorrow. Thanks. Commented Oct 9, 2016 at 19:14
  • So could I just loosen the alternator tensioner enough to let me clamp the belt next to it and next to the crank pully and that would be sufficient to tighten / loosen the crank bolt? Commented Oct 9, 2016 at 20:06
  • 1
    Thanks, the trick worked and I added a picture of how I did it to the post. Commented Nov 10, 2016 at 19:13

It depends on the design of the particular crankshaft pulley on your vehicle. Some of them have bolt holes specifically for this purpose; if that description matches yours, then what some people do is drill 3 holes in a long 2x4 piece of lumber (1 for access to the large bolt you wish to loosen, and 2 smaller ones to coincide with the holes on the pulley.) You then use either the frame of the vehicle or the floor as a point of leverage for the far end of the board, while you heave on your breaker bar (when loosening) or torque wrench (when installing) through your larger hole in the board.

Other vehicles (such as a Honda Odyssey) have a recessed area that a special tool fits into. On such a design, your only viable choices are to acquire that tool, or blip the starter.

Also, many big-name auto parts stores have tool loaner programs, which often include several styles of pulley-pullers. Often the loaner just requires a deposit which is 100% refunded on return of the tool.

Please note that the blip-the-starter method is only safe to do if your crankshaft turns clockwise, and your pulley bolt has right-handed threads.

  • You mean righty tighty lefty Loosey isn't Universal? Commented Oct 9, 2016 at 7:06
  • Correct, not universal. Especially on parts that spin. edit I guess my final warning about blipping the starter might only apply when there is a mismatch between crank direction and bolt handedness. Commented Oct 9, 2016 at 7:11

This is the contrarian answer. There are impact tools, usually 1/2" drive, which have a cam in them. When you hit them with a hammer, they will apply impact to a socket. Even though I have several, and some large impact tools, I will sometimes use one of these hand tools to break free a fastener. The prices vary but $20 seemed pretty typical for a heavier unit a few years ago.

Once you use one of these, you can get pretty handy with them. For example, playing with tightening tire lugs, can with your calibrated hammer and calibrated hand, help you ball park the torque when reassembling. Not to aerospace specifications, but possibly good enough for your application.

The benefit of using impact is that you don't have to hold the shaft, which as you know is quite difficult with an automatic transmission.

  • You mean like the Lisle 30200 Impact? Nice idea, might have to try it next time I do timing on an automatic. amazon.com/Lisle-30200-Hand-Impact-Tool/dp/B000P0TZ9W Commented Feb 19, 2019 at 12:14
  • Exactly. Something similar was $20 or less at Sears, back when Sears had tools, or even existed. If one plays with their hammer, you can get a predesired torque within about 20 to 30%. I would not bet a 747 full of passengers on it, but for junk yard mechanics, it might work OK. Has for me. Practice the day of the tightening helps, for tightening. Determination the day of loosening helps.
    – mongo
    Commented Feb 19, 2019 at 13:43

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