Terrible Shake when Brake is applied

I have a 2002 Toyota 4 Runner, that shakes terribly when I apply the brake to slow down. My repair guy said the brakes are fine and often he cannot get the truck to shake when he drives it, he said the alignment could be part of the problem, but even when aligned properly the wheel shakes. Any suggestions on what the heck is causing this?

Probably warped rotors.

my repair guy is pretty concervative, and says my brakes are at 60%. I will let him know to check them out.
Thanks for your reply.

The brake wear has no indication on whether or not your rotors are warped. You need to have them check the rotors for warping with a dial indicator, or an experienced foot on the brake. My money is on your rotors. It could be loose/worn bearings, suspension or steering parts, but I’m still betting your rotors are warped since it only takes one instance of overheating the rotors for them to get warped, especially if they were turned once already.

SUPER appreciate your feedback. I have an appointment on Monday to have my guy check it out.
Thanks again!

Or maybe a sensitive ABS.