I have a 1991 f250 with Dana 50 ttb and i just replaced my hubs i cant find the spring to go behind the hub cap and new hubs didn't come with any. can anyone tell me were i could buy the springs that engage the 4x4 when you lock the hub

 

I don't know of anywhere to get the spring, besides pulling one from a junkyard. Sorry!

 

Contact the company that makes the hubs.

 

I have enother question the drive shaft keeps pulling out my right hub its dun it 3 times now dont understand why was told possibly shaft is to short .

 

Sounds like a potentially stuck slip joint and missing circlip. There should be a clip on the end of the stub shaft, visible when you remove the lockout cap. It keeps the stub shaft in the lockout.