Fibreglass Bathtub Leaks Need Help

[Cookerz]

Hey Guys,
I'm having an some trouble with a fibreglass bathtub,
it has been corked (mastic) many times, but after a few weeks the water starts coming through where the mastic joins the bathtub and wall and leaking downstairs.
The leak mainly starts from where the two walls meet (but around the frame of the bathtub)

Does anyone know of some way of creatively / cost effectively fix the problem?
Any advice would be appreciated.
C

[phishfood]

Is this a fiberglass tub with matching fiberglass walls that sit on top of the rim of the tub? Or are the walls tiled down to the tub? I am not quite sure from your explanation.

[majakdragon]

The problem is that the tub was not set on a mortarbed when installed. This allows the tub to flex when anyone steps into it. What "may" help is to put as much weight into the tub as you can, including water. Recaulk the joint of the tub and wall. Allow the caulk/mastic to dry thoroughly before draining and removing the weight. This allows for "pre-flexing" the tub.