Rag Joint Pinch Bolts
A common mistake with rag joints (flexible couplings) is to think that loosening its "pinch" bolt is all that's required to remove the rag joint from the steering gearbox. Loosening the bolt is not enough, the bolt must be removed from the rag joint for it to slip off the input shaft. The same goes for installation - insert the bolt after the rag joint is positioned on the shaft.
1977 and up had a bolt head with 6 points, prior to 1977 they were 12 point bolts, so you'll need a 12 point socket for these.