When the rag joint (or steering coupler) wears out the steering becomes loose. You can either order a rebuilt one from a specialist vendor for +/- $90 or a DIY kit for +/- $20. With that price difference you should DIY. Here's my beginners guide.
The brake power booster & master cylinder were already disassembled from my car because of an engine rebuild. This makes unbolting the rag joint very easy (please do a search for how to remove the rag joint in another fashion). Just undo the two screws at either end, remove the three bolts that attach the steering box to the frame rails and pull it back an inch or two. The rag joint now slides out.
Above are the parts the rebuild kit consist of. In order to fit the new parts the old rivets have to be drilled out first (using an 8 millimetre drill as a maximum). As I understand it #2 #3 or #4 are to be used in position E. The idea is that if the new 'donut' ever gives way the tabs will minimize steering wheel play because they will get caught by the big metal piece of the bottom halve of the rag joint assembly that connects to the steering box (the one with the splines). I do not know what #1 should be used for. As a precaution I'm going to replace the standard nuts for nyloc nut.
Please note that the nut and bolt at position E aren't original.
Don't forget the little ground wire (or end up with electrical problems with your horn)!
The rebuilt rag joint is back in its place. The first photo shows a wrong rebuilt/installation, the second photo a right rebuilt/installation. Here you see one stud pointing towards the firewall. If there's play in the shift tube (because of a worn or even missing lower shift tube bushing) the shift tube could come into contact with the stud & possibly making the car shift gears. Imagine getting out of your car. You always brush past or touch the steering wheel.
In this photo only the stud remains that points downward to the steering box. The idea is that if the new 'donut' ever gives way this stud will minimize steering wheel play because it will get caught by the big metal piece of the bottom halve of the rag joint assembly that connects to the steering box (the one with splines).
There's a nice surprise behind the splash shield in the left front wheel well. This little opening should make working on the rag joint much easier. My friend Peter thinks this is where the speed control fits for cars fitted with one.
Note the old piece of rubber fuel line. I bet you did not know that it is even there. Replace it because after 50 years it´s a fire hazard.