why does my bronco lift up when i brake?

[mauibronco]

hey you guys...another stupid question for all the experts out there...I recently bought a 1970 with a 3 1/2 susp. lift and 2 body lift and lengthened drive shafts,also the cross member was lowered a bit to better the drive line angles... when i am at a stop, let my foot off the brake then depress the brake again, i notice that the entire truck feels like it raises an inch or too. I have a 73 with only 2 1/2 susp. lift and have never had this happen before...I'm wondering if maybe this has to do with the driveshaft, or what is causing this. also, I am wondering if this needs to be fixed/ how to fix it, or if its no big deal?

thanks in advance for all of your help!!!

 

[cvbfireman]

i know what your talking about but i have no clue...

BUT.... If i had to guess i would say when you hit the brakes while moving your axle probably shifts forward a bit causing the front to go down then when your stopped and let off the brakes it probably straightens out and pressing the brakes again doesnt twist the axle because theres nothing moving.... Just a Guess

 

[Broncobowsher]

Interaction between brakes and suspension. You do have functional brakes on both axles, I am sure of that. Any further and it would be a guess.

Next time you get a cheap rental car, get a Versa. Do a panic stop. When you let off the brakes you can feel the rear end drop an inch or two. I have been in a few different vehicles that did stuff like that. Even my motorcycle will hold a preload on the suspension if you come to a complete stop hard with both brakes. release either brake and the suspension will relax and the posture will return to normal. Never worried about it on any of them.