Bryan's awesome sensor change/distributor directions. Pay attention!
The only way to get the sensor out is to disassemble the distributor. Not sure if you have ever removed a distributor, so I will give you the basic steps. The first thing to do is to put the rotor back on and mark the position of the rotor and shaft/plate to the distributor housing. Now make those marks very precise, you will need them to reinstall the distributor in the correct position which is very, very important. If you wanted to do this by the book and set the engine at Top Dead Center, then you need to turn the engine untill the dist rotor lines up with the #1 spark plug terminal on the dist cap. Use the starter to get it close and then turn the engine by hand with a ratchet and a 19mm socket on the front crankshaft bolt untill the timing mark on the crank pulley is lined up with the 0 mark on the scale on the timing chain cover. I think if you make the marks easy to read and realign, this is not needed.
Once you have the marks set, remove the distributor by removing the hold down bolt and bracket. Once the bolt is out, just pull straight up on the distributor, you may need to turn it slightly from side to side to make it come out easily. The center shaft will rotate slightly when removing the dist. Make a mental note of the direction and relative position of the shaft once it is removed as this will help during reinstallation. Also once the dist is removed, do not crank the engine. OK, once the dist is out, you will need to remove the small drive gear. It is also important to mark the gear position on the shaft. It is important to reinstall this gear exactly in the same position as when you removed it. Make a mark so you know which way is up, as well as its orientation, you don't want to install this 180* out of phase on the shaft. The gear is held in place with a roll pin. Use a punch to dive out the pin from the gear and shaft. Once the pin is out, you will need to drive the shaft out the top of the dist. This may prove to be somewhat difficult, you might need a dist gear puller, but I would try holding the dist in a vise, and use a soft face hammer to drive out the shaft. Use a plastic, or rubber dead blow hammer for this, a regular type hammer will damage the shaft and you will be screwed. You may also need a brass punch to drive the shaft all the way through the dist gear. Once the shaft is out, you will need to replace the sensor. The cam sensor is held on with a small bolt, or a snap ring.
To reinstall the dist, just line up the marks you made when you removed it. One tooth off in either direction will cause a no start condition, so be very precise in making and realigning the dist. Also pay attention to the oil pump dive shaft in the block. The end of the dist drives this shaft. If you install the dist in the wrong position the first time you try, which is common, this shaft will move slightly and may prevent the dist from fully dropping down into position once it is aligned properly. If this happens, just use a long, flat blade screwdriver to move the shaft. This process will take a few tries to get everything line up, but patience and accuracy are very important.
