yes, you need rear brake extensions. Here you can see the red rear Extensions and the slack required on my 3.5" Clayton lift. If you zoom in, you can see that the Abs sensors have also been zip tied to the red brake extensions. For me there was plenty of slack to do that after I released some ABS zip ties. Make sure you bleed the brakes afterwards.Have a Teraflex 4.5” lift I’m getting ready to install. It occurred to me that I probably need brake line extensions. Is that correct?