Hillbilly plumbing

All DWV here IS sch 40. That said the P-trap is not! First step, as said above, dig the hair out! Mmm, Beautiful, luxurious Hair! Lol, IF that doesn't work You CAN give 'er a few, little, gentle "bumps"with, what should not be, No More than 35-40 psi, from a compressor. The overflow on the high side of the tub above the drain, if you can remove that and stick a wet rag in it, will help, by blocking bypass air. That can help clear the P trap Some homes actually have an access to the P-trap on the back side of the wet wall of the shower (meaning the wall THE plumbing is in) You can pick up a tub drain removal tool for a few bucks at Home Depot/ Lowes( or for a few bucks less at Harbor Freight) even though I hate buying their Chicom crap, it's all from China anyhow..thing you need to do is find out where you think the clog is. Start from the high side push it down to the street! I agree with some of the posts above. Hair/ soap, is the Usual Suspect in a Shower/ Tub. Also, many clogs have been PUSHED downhill, using the wet rag method and a garden hose through the roof vent on that battery. Using a Snake on something like that, is generally overkill, and kind of a waste of time, unless You HAVE A waste blockage.. I've been really beat the hell up and after 6 weeks of CV induced bronchitis...so I ain't getting into a "pissin" Contest... the whole point is it's almost like working on one of these old cars start at the root of it, ( hope Ya ain't got ROOTS in the Main Waste line!) And slowly work to it from the top side down ! Peace Y'ALL, and God Bless