What happens when you do a power brake without the line lock? Will power of the rear wheels overcome the front brakes and the front wheels start to roll?

If it did not hold it before it is not going to with the line lock now.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.