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How to remove and replace crankshaft hub bolt with hand tools

If you have to remove your crankshaft hub bolt in order to replace your timing belt (if you have Bentley's "two-piece crankshaft hub") then this trick will come in handy for you. I removed my bolt before I realized that I didn't need to, so I had to figure out how to do it, even though my car has the one-piece hub. This will work on my car, but I can't speak for other cars. If two-piece hub cars are a little different, this may not work at all.

The problem is that the crankshaft hub bolt is torqued to a massive 302 ft-lbs of torque. Yikes. If you have fancy pneumatic equipment, you're already set up for this, so read no further, but if you're a plebe like me, and you have to make do with hand tools, you'll want to read this.

First, you'll need to remove the bolt. For this, we can employ the power of the car's starter motor. The torque multiplier gearing of a starter is huge, allowing it to turn over the engine, so it's perfectly capable of loosening this bolt. To do this, get a breaker bar, 1/2 or 3/4 drive, with a 22mm socket. The bar will need to be about 2 feet long. Put the socket on the crankshaft hub bolt, and rest the breaker bar on the driver's side of the engine compartment. I put a block of wood under the breaker bar to keep it from damaging the metal. When the starter turns, it will turn over the engine (including the crankshaft), pushing the breaker bar against the side of the engine until the bolt gives way and loosens. Just get in the car, and turn the key very briefly to the start position. Only a little turn is needed to loosen the bolt.

There are a few things the be careful of. One, you want to have everyone stand back while you do this. I know it works, but it's best to be on the safe side. Two, make sure the breaker bar is resting on the driver's side of the engine compartment. It must be on that side, or when you turn the key the bar will spin all the way around and smash into the driver's side of the engine compartment with a spectacular bang, causing damage to you car. Three, you want to make sure your engine doesn't get any funny ideas and actually start when you do this. I accomplished this by insuring that the spark plug wouldn't fire. Since I had the distributor rotor off anyway, this wasn't an issue, but if you're doing this with the rotor and cap installed, make sure you take them off, or disconnect the plug wires or something.

Once this bolt is off and you've done your business, the time will come the reinstall it. You can't do it the same way you took it off, because the engine only turns one way. To reinstall the bolt, you'll need something to hold the crankshaft steady with while you tighten the bolt. Bentley recommends BMW special tool # 11 2 150. Very helpful. Since no one has this tool or is going to buy it for $70 from the dealer, another method of removing the bolt is necessary. Wrap your old timing belt around the teeth on the vibration damper and clamp it tightly with vise grips. Now rotate the crankshaft clockwise, using the crankshaft hub bolt, until the vise grips are wedge in under the water pump. Use you breaker bar (or a big torque wrench if you want) to tighten the bolt. I was able to put about 125-150 ft-lbs on the bolt before I started to get nervous about the water pump. I spoke with a mechanic at my BMW dealer, and he said that 150 ft-lbs is plenty as long as I put locktite on the threads. So I picked up some blue (medium) locktite at O'Reilley's and satisfied myself with 150 ft-lbs. I haven't had a problem since and don't expect I will.

This method is a little unorthodox, but it works. It is tried and true, as I have personally done it to my car. I can't guarantee it will work for you, but it's a great option it you don't have access to impact wrenches or BMW special tools.