If the chemical, the plunger or the hot water treatments do not open the clogged drain, the drum trap cover will have to be removed. The drum trap is usually mounted directly underneath the tub (Fig 7).
Removing the drum trap cover can be extremely difficult. First, apply a good grade of penetrating oil to the drum trap cover, let it sit a while and then attempt to remove the cover with a large wrench. Turn coutner-clockwise to remove the cover.
If you cannot budge it with a wrench, it may be necessary to cut notches (Fig. 8), in the cover edge with a hacksaw. A hammer and punch or cold chisel can then be used to remove the cover.
Once the cover is removed, a drain auger can be used to unclog the stopped pipes.