So i beat the game and during the ending sequence it says the followers got pushed out of the old fort and according to the vault wiki theres a ending that they dont. What do i have to do to get that ending, there no dialog or anything with the Followers leader about helping the ncr or anything.

Just a guess but I would think you would have to side with Mr House/Yes Man to get there good ending. I doubt the Legion would leave them be and I know NCR doesn't.

Legion ending pushes them out, NCR pushes them out, mr house ending didnt.
I dont understand why the NCR kicked them out though...

well accoring to the vault wiki theres a ending where the followers helped the ncr by giving them medical aid and in turn the ncr allowed them to stay yet there was no dialog to ask them to help also its said this ending is obtained by joining them which i did but it gave me the ending for not joining them. i find it kinda funny that if this is a glitch the followers correct ending have been glitched for both fallout 1 and New vegas.