I just replaced my bathroom centerset faucet and all went well... until it came to replacing the pop up stopper apparatus. I could loosen the nut that holds the apparatus securely to the sink, but I can't remove the apparatus entirely.

As you can see from the pictures, the old apparatus is made of metal. The ring on top of the sink does not unscrew as the new plastic versions do. Also where the lift rod connects to the drain I can't unscrew this either. Basically what happens is I can unscrew the nut under the sink, but it stops once it reaches to part of the drain where the lift rod is inserted.

Can anyone help me get rid of this stupid apparatus so I can install the new one? Also, what kind of tool would I need to remove my old p-trap? I'm really struggling here!

See below.

Hmmmmmmmm, I would try a hacksaw and just cut out the metal crap, try to wiggle that end out of the sink, and get a coupler to tie in some new pvc to the drain out of the wall.

Take a large set of pliers and give it another try. The larger pliers you use - the more leverage you will have.
You have the type of drain that requires you to unscrew the pop up assembly nut (located on the side of the drain) from the drain piece itself in order to remove the large nut in downward motion from the drain.
Unscrew the pop up nut and slip the large not out. Drain itself may be tightly in. Tap it gently with a hammer on the bottom of the drain in upward motion. It should let go.
If nothing else works, take a hacksaw and saw the drain off between the nut and bottom of the sink.

Thanks for the prompt responses. I'll try that in the morning.

Also, by looking at the p-trap below... how would I remove this? There are no coupling nuts (I believe that's what they are called). It almost seems like it is glued together. How would I remove and replace this? Thanks a bunch in advance.

That nut under the sink is not going to pass over the outlet for the pop up rod. Therefore the sink flange has to unscrew. Loosen the nut as much a possible, push the drain assembly up. You should then be able to grasp the sink flange with a pair of pliers and unscrew while holding the drain assembly underneath the sink.

Harold,

If that flange unscrews then I'm simply not strong enough to unscrew it! I did exactly what you said and used ALL my might to unscrew the flange. No go... would your recommend using a hacksaw... and what do you suggest for the p-trap?

Thanks!

Regarding P-trap removal:

Cut the PVC pipe on the horizontal section with hacksaw. Cut it in the middle. Unscrew the nut on the vertical piece. (usually hand tied). Then you will be able to remove P-trap in downward motion. To reinstall: Buy a new 1 1/2" coupling and small can of PVC glue. Glue the coupling on the horizontal pipe, then, glue the P-trap section onto the coupling. You are done.

Or, you may use Flex-Seal coupling or No-Hub coupling to join these two pipes together. Here, you don't have to use glue. The coupling slips over each end of the pipe. It has two s.s. band that you tighten with 9/16" wrench or screwdriver. This may be the cleaner way of reinstalling your old P-trap.

Don't mess with flange. That flange is an extension of the drain piece. It cannot be removed. It is one piece of continuous pipe. It is clearly visible in posted photo.

Yes, you can cut it. Be kind of slow with a hacksaw. Do you have a saws all? Could cut it with a saber (jig) saw and a metal cutting blade if you can get the saw up to it. To remove the drain tail pipe loosens the nut at the top of the picture after removing the drain assembly. The tail pipe will unscrew from the pop up assembly. The trap is a glued up trap and can only be removed by cutting out. Cut just behind the ell with just about any kind of saw. Remove the trap. Purchase a escutcheon for 1 1/2" PVC, slip on pipe to cover the hole in the wall. It may not fit tight against the wall because of the fitting in the wall but it will help appearances some. Recut pipe at least 1 or 1/12" from wall making a nice square cut. Purchase a trap adapter fitting. These look like a male threaded pipe adapter but are slightly larger on the inside to accept the arm of a trap. The trap adapter and the male threaded fitting are very similar and its hard to tell the difference. The trap adapter will come nylon seal and a compression nut. When purchasing slip a trap arm in the fitting to make sure you have the correct one. Glue the adapter on the stub out coming out of the wall. Personally I prefer this type of trap set up because you can slid the trap arm in and out of the pipe and swing the trap left and right to align it with the drain perfectly

Do I need a second trap adapter to connect my new sink drain assembly or will it just hook right into a new p-trap?

No,
Trap will come with compression fitting to accept tail pipe from sink pop up assembly.