This is my 1st post and I couldn't find this in any other threads. I apologise if this is a duplicated question. I recently remodeled an older (mid 50's) built home bathroom with galvanized pipes. I noticed a large deposit build-up in the hot water line when I replaced the tub faucet/diverter valve. After installation, I cleaned out the sediment that came loose, but now I have a hellacious whistle/squeal when I turn on the shower. The sound does not occur when I turn on the faucet, only once the diverter has put the water to the shower head. Any suggestion for a cure? If it matters, the valve/diverter is a Delta manufactured unit.

I have a jetted tub and the drain plug is jammed shut, so I cannot open the drain. The knob/rod mechanism cannot exert enough force to pop it up, and so I cannot drain the tub. I've taken apart as much of the mechanism as I can but can't get good enough access/leverage to the plug to pop it loose. I've also tried a combination of pressure on the lever (pushing it up from the bottom) and suction on top (pulling it up from above) with no luck. So far the only suction mechanism I've used is a plunger, but I'm thinking about trying something like the suction lifters used to carry sheets of glass. I'm not sure how much force I can exert before I hurt the tub, which is made of plastic. I could also drill a hole in the plug, use a screw or something to pull it up, and replace the plug, but I'm not sure how readily available such a part is. Is there a smart way to fix this without dismantling the tile around the tub?