Front End Popping Noise When Braking Options

[Cheatham]

1998 T100 4x4 xcab, 54k miles
I have a front end popping noise that happens when braking firmly (not the steering stops). The Toyota dealership has spent hours in attempt to diagnose but failed. They checked all they could think of including brakes, ball joints, upper/lower control arms, engine mounts, cross members, etc... The pop is audible from inside and outside the cab and seems to be located low in the passenger side front end area. You can hear it pop this shift back/resetting somewhat. The dealer's advised all was safe and to drive it until it became so bad that they could tell what it is. Well, I'm impatient and would like this resolved sooner than later. Has anyone experienced a similar popping noise that can help? Thanks.