i need to change out my universial joints but i cant figure out what size is the bolt that holds the driveshaft on i have a 2003 f150 xlt off road but ih ave tried a 12mm socket and its to little can anyone help me out

 

Make sure it is a 12 point socket or wrench

 

yes i thought it was going to be a 12mm wrench but it didnt fit so i went up to a 14mm or 15 and it was to big so its in between a 12 and 15 just dont know what it could be?

 

13mm is a popular metric size becuz its just a hair over 1/2". But i've never seen anything but 12mm AND 12 pt as already mentioned. You may have odd ball that some one has swapped bolts for some reason. Also make sure the splines on the bolt head aren't messed up by someone like previous owner. Those bolts can be very hard to break loose if they have never been off, and someone may have beat the crap out trying to get them loose and messed up the head. rossford

 

well my dad bought the truck brand new off the lot some it has had only 1 owner

 

12mm 12 point..