Update
 

No success to date in removing the Speed Sensor. I have spent many hours on this problem; by comparison, it took less than 5 minutes to remove the Reference Sensor from the same bracket. After using nearly a full can of PB Blaster over a period of three weeks, I finally got the Speed Sensor to move freely in circular motion, and about 1/2 inch out of the bracket. But, after much additional effort, it appears unlikely that it will come out any farther. Either debris from the flywheel damaged the metal casing or I have a serious corrosion problem; I suspect the former. Opinions welcome. If I intentionally break the bracket can I install a replacement bracket over the roller pin located at the pivot bolt, with no sensor installed? To wit, does the design (so-called) of the bracket-roller pin combination allow the bracket to be removed/installed after both sensors are removed? It isn’t clear to me from previous posts on this subject. Specifically, bazar01 above says he had to shave down the roller pin (sleeve) to install his bracket; but he doesn’t say whether the sensors were installed when he attempted to reinstall the bracket. Obviously, it doesn’t make a lot of sense to intentionally break the bracket, if I cannot install a replacement without removing the bell housing. One last comment, on my 944, it appears that the roller pin isn’t even a solid piece of metal; I can only get a partial view of the pin with a mirror, but it appears to be a piece of small gauge metal that has been formed into a circle, with the two mating surfaces butted together. Of course, I have no idea how far it extends into its mounting surface. Probably not more than a few “feet” but who knows with this design (so-called).

I had my bellhousing off at the time, so I cannot say for sure, but from what I read on the subject, I assume it would go back on without the sensor installed. But since bazar01 had trouble and installing it with the sensor in place is so counter-intuitive, maybe there are difficulties I don't understand.

One thing I found while clearancing the sensor with the bellhousing off with a feeler gauge. There are 2 bolts that secure the bracket. One that goes inside the pin, and one that goes through a slot that allows the bracket to be adjusted. The slotted hole seemed to be through a tapered plane. Meaning that as I tightened that blot past snug, it would alter my clearance. I decided that the bolt through the slot determined the clearance, and the bolt through the pin locked the bracket in place. If that is obvious in other sources (Haynes, or Clark's Garage) sorry for being redundant, but my experience said to me not to tighten the bolt through the slot after clearancing the sensor.

Sorry for not making myself clear. I just finished my torque tube and clutch rebuild this past weekend. I thought that the bracket without the single sensor (speed and ref in one) would go in with no problem. I was wrong.

When I put the bracket back, without sensor, it won't go in because the hollow tubular dowel pin on the pivot bolt was interfering. I did not want to go back to square one so I tried to grind down the dowel to almost half to get the bracket in place. Then when it went in, what a relief, I installed the sensor with the 0.8mm washer glued to the tip then secured it with the top bolt. Tightened the adjustment bolt then the pinned bolt last. Now my car is back on the road.

Your sensor must have been mushroomed by debris in the flywheel or probably hit the flywheel when initially set for clearance.
The only way would be to destroy the sensor maybe by drilling it in the middle. But be careful not to destroy the sensor sleeve if you want to save the bracket
Good luck

Success
 

Success! This is an edited version of an earlier post. I finally got the speed sensor out in one piece; the physical appearance was generally good. No damage by debris (as I had speculated), but some corrosion. The sensor was being held firmly by the o-ring and corrosion. Many thanks to all on the site who assisted me in this task. Great site. For the potential benefit of others, the primary tools I used were (1) extreme patience, (2) 11-inch needle nose pliers, (3) 12-inch channel lock pliers, and (4) PB Blaster. For improved access, I removed the pipe brackets and heater valve above the sensor. Initially, I was unable to move the sensor at all. I applied PB Blaster and allowed it to sit overnight (a procedure I was to repeat a number of times), and eventually I was able to move the sensor a small amount laterally, but not vertically. I wanted to avoid moving the sensor mounting bracket to obviate the need to clearance the new sensor when installed. But my patience waned, and based on some bad information, I decided to remove the bracket (“just remove the two bolts and the bracket will lift right out”). Wrong! The sensor mounting bracket cannot be removed with the speed sensor installed, because there is insufficent space to move the bracket forward to clear the roller pin (sleeve) at the locking bolt! I did confirm, however, that once the speed sensor is removed the bracket will clear the roller pin and can be removed. Early on, I considered breaking the bracket (a used replacement was available for only $30), but I wasn’t sure at that time I could install the replacement bracket without filing down the roller pin. I can now state that if the speed sensor will not come out, breaking the bracket is an alternative – I would think preferable to pulling the bellhousing. Thus, I continued to twist and turn the speed sensor, working a few hours every day or so. After a period of about three weeks, the sensor moved freely laterally, and I managed to pull the sensor out of the bracket about ½ inch. Finally, using a rubber mallet, 12-inch punch, and 11-inch needle nose pliers, I alternately knocked the sensor back into the bracket and pulled it out, and after several cycles – success – the sensor came out. After this ordeal, installing the sensors and setting the clearance should be a piece of cake. Getting the hex bolts back into the mounting bracket will require some additional patience.

congrats !

(I wudda given up long ago)

good infomation too