96 Buick PA Trying to replace the crank position sensor got the belt off the pulleys...problem is im stuck on the vibration damper bolt. Can't seem to budge it with a breaker 3 or 4 ext or a 230b air impact wrench. What is my next step?? Can I remove this crank sensor somehow without taking the damper pulley off??

Which one ? your vehicle has two !
Crankshaft Position (CKP) Sensor (7X)
Lower rear of the engine block, below the exhaust manifold
Crankshaft Position (CKP) Sensor (24X)
Right side of engine, at the end of the crankshaft, behind the harmonic balancer
24x replacement .
Turn OFF the ignition. Remove the serpentine drive belt from crankshaft pulley. Refer to Drive Belt Replacement in Engine Mechanical. Raise the vehicle on hoist. Refer to Lifting and Jacking the Vehicle in general information. Remove the crankshaft harmonic balancer. Refer to Crankshaft Balancer Replacement in Engine Mechanical. Note the routing of sensor harness before removal. Remove the harness retaining clip with bolt (1). Disconnect the sensor electrical connector. Remove the sensor bolts (2). Remove the sensor.
After replacement of this one you have to do relearn
24x 24

Most crankshaft sensors are located on the right side of the crank pulley or Vibration Damper as most call it. It is mounted on the front of the engine next to the pulley so as to sense pulses from the pully. If it is not there, look toward the back of the engine where the distributor used to be on older models. It will have a black cover with various color wires coming out of it.
I hope this is of some help.

Crank position sensor. Sounds exactly like thats what your problem is. If your not mechanically inclined then it is not a job you want to attempt. If you are then it will be a cheap repair in terms of $ value anyway. The sensor is bolted centimeters from the crank pulley behind your timing belt not the harmonic balancer but the pulley behind that. Hope this helps you out. good luck.

They are sometimes installed with threadlock compound which makes it very difficult. How big and powerful was the impact wrench? Is there scope yet to hire a really huge one?

The bump method is a last resort because it puts the flywheel ring gear teeth at some risk. Break one of those and you are up for expense.
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The crank pulley

The bottom pulley on any engine is attached directly to the torsional vibration damper which is attached to the crankshaft. That pulley drives the serpentine belt and has no bearings. First thing you need to do is find out if the pulley bolts have become loose or if the damper on the crank is loose.
If you find the pulley loose, if the bolt holes are not elongated, just tighten it back up. If the damper is loose, remove it from the engine (puller usually necessary) and inspect the crank snout and the alignment key for wear. Any damage to the damper requires that it be replaced. If the crank snout is severely damaged, that requires that the crank itself be replaced (very expensive).

The crank shaft flywheel is on the other end

You have to replace a worn crank damper pulley

The crankshaft position sensor should be located behind the vibration damper/harmonic balancer and it will have to be removed before the crankshaft position sensor can be replaced. (Let me know if you require assistance with the proceedure)

Also, it usually requires a special tool to align that sensor (available from most auto part stores) and if the sensor is not properly aligned then damage to the sensor or the tone ring can occur.

Here is an image of the crankshaft position sensor with the vibration damper/harmonic balancer removed.

Crank sensor is not in the crank case itself... it is behind the Flywheel pully...the one that turns all the belts!! Impact the bolt out and you will need a puller to remove the pulley... the sensor is behind the pulley and held on with 2 bolts.

Hi I'm litoshop the bottom pulley is the damper that damper could be broken if you tighten the crankshaft bolt and the pulley is not aligned then you may need to replace the damper and when you replace the damper before you put the bolt on use a little lock tite it's a liquid us mechanics use when we don't want a bolt to loosen so easy. if this information has been helpful please let us know thank you and good luck