No hot water on second floor

Looking for a little help

I lost hot water on the second floor at both the shower and the sink. Out of no where it was reduced to a trickle, though it seems to have great pressure. I am unable to hold my thumb over the spout to stop the water for more than a few seconds. Have already checked the cartridge in the delta 1500 single handle valve and it still rattles. Guessing it is ok, but when first trying to get the brass bonnet off the valve body, I managed to turn the brass cylinder on the valve body and cold water seems to be restricted now. Let the bonnet soak up a good deal of WD-40 over night and it spun right off. When re-assembling I was able to turn the cylinder on the valve body back clockwise, but cold is still restricted.

Any suggestions on the hot water supply - I am wondering if there might be some old packing jammed in the line to the upstairs.

Also, have I broken the delta shower valve or can it be torqued back clockwise.

Thanks

From what I've read here, you've likely ruined the valve.

Are any of the pipes galvanized in the house? If so, it might be time to repipe.

No galvanized pipe. Pressure just went from great to trickle overnight.