rotors caused death wobble???

So I found out that the front rotors were causing DW on my friends '97 XJ. I'm honestly baffeled as to how brake rotors could cause DW. After we did the rotors she went and test drove it and the DW was gone.

Could anyone dumb it down and explain to me how this could happen?

Just dealt with the same issue on my 96. It had a slight wobble on the highway. Yet if you stepped on the brake and turned while going highway speeds it would cause serious death wobble. I found that the shake was from the rotors but was magnified because of worn lower control arms bushings. Be sure to check the bushings on the lower control arms and the lower ball joints. I bet they are just worn a bit and having the rotor issue was the shimmy issue and having worn bushings and joints magnified a simple problem.

Agree with Jeepm@n, the rotors were likely triggering an already existing problem. Check all the suspension/steering components very carefully.