violent shake in front end when braking

a mechanic can scan for codes as well to see if it is an ABS problem, but your brake light on dash would be on as well.

has new rotors, brakes, a arm assembly, balance, wheel bearings, everything but tie rod ends and they are good. I have spent close to $1,500.00 at three different shops to no avail.

have you checked the tires for a bulge or something like that? Normally they would do it all the time, but if it happens like you say with all the parts you have replaced there is something wrong with the front end or the ABS. A mechanic should be able to get a code for it.

tires are about half worn, but did check and they are good. besides it did it before I got these new.

have the sub-frame mounts checked that is the frame where engine and transmission are mounted to the body. also, check motor and transmission mounts it may be moving when you hit the brakes.

unplugged speed sensor wires on front hubs and shaking stopped so must be in abs somewhere

Yep that's what it sounds like, it could be a WSS problem, I would test them all, here is a guide on how to do that,

https://www.2carpros.com/articles/abs-wheel-speed-sensor-test

Please let us know happens so it will help others.

Best, Ken