The cold water flow was weak in a bathroom sink, and the hot water flow was almost non-existent.
Both shutoffs were initially frozen but thankfully loosened up over time with a bit of patience.
I had a gifted 1-hole heavy duty replacement faucet which I intended on installing at first.
The replacement faucet turned out to be too tall and interfered with the cabinet doors above. Bummer.
(Always measure twice. Take parts in with you to match up..blah blah )
It needed a couple of foot long 3/8" 3/8"M/F-type hose extensions to reach the shutoffs. Sometimes they have to be extra long to not kink. Depends on the installation.
(Many are now 1/2" connections so double-check everything before you start driving to the store)
While getting my fat butt off the floor, the countertop shifted and almost fell on top of me. It was not attached to the cabinets. wtf That's also when I discovered the sink drain was never connected after all these years of use. These pieces were just touching but somehow never leaked. wtf again
The pic doesn't show it but there was a noticeable 1/4" gap there. The finished trim surround was nailed/glued to the wall so the countertop was shimmed, then brackets. The countertop was only supported in four spots and needed more anyways.
First things first.
I removed the diffuser/aerator to help water move. Both shutoff valves were back on but now there was zero water flow hot or cold. Huh? Both shutoff valves could not be faulty at the same time. Must be the faucet. I opened the sink handle and hammered lightly all around the base for about five minutes until the faucet puked up a couple of pea-sized chunks of pink calcium rock.
(a few layers of blue tape to avoid scratches) Now there was cold water but what about hot? Turned the valve back to hot and all the water stopped again. Crap. Turned the handle back to cold and banged on it another five minutes until it flowed again.
A nice fat and even ring of cushy plumber's putty around the new drain helped it bed in nice and flush. Scrape off the extra which squishes out. I use silicone grease on the PVC ring seals and rubber. I use tape on the threads (wrap clockwise when you're looking at the open end, not too much, and start at second thread). Work nice and slow. Don't over-tighten when working with rubber or ceramics.
A few fittings needed to be loosened so all the PVC would line up before tightening.
The sink is secure and half-way works for now. The shutoff valves have been exercised turn and seal. Hammering finally got the grit out and full pressure again. Everything cleaned up. The small things in life.