i am going to replace the rag joint with a u-joint. i searched on here but couldn't find my answer. i don't have the truck here right now but as soon as i get it i want to remove the rag joint and weld in a u-joint assembly in it's place. my two questions are what size shaft is the steering shaft? and how many splines is the end that hooks to the steering gear? i am looking at something like this in of corse the proper size. Steering Shaft U-Joint Coupler 3/4" x 3/4"-30 Spline | eBay my truck is a 78 f-150 4x4.

 

According to the Borgeson catalog, it's 3/4" x 36 splines.

 

thanks for the quick response. so this is what i am looking at what i need then. Steering Universal U-Joint Coupler 3/4-36 Spline IMCA | eBay i have a buddy at work that has a turning lathe that said if i get him the shaft and the u-joint he will weld it inside the turning lathe to make sure it is straight.

 

When you cut shaft to length set steering column slotted hole base bolts to bottomed out so when you need to service something you loosen the base bolts and pull it up so u joint comes off splines on steering box

 

With the cab movement on the frame you might want a slip joint of some kind on the shaft, all vehicles with a body on a frame are built with a sliding collum of some sort (or rag joint).
The upper collum bearing might have trouble by being loaded with up and down movement.
just my 2 cents.

 

thanks for the info guys. i was thinking i was going to pull the rag joint off then i was going to slide the u-joint in place and then mark the shaft and cut it so it has the same travel as it did with the rag joint. i know what you guys are talking about with having to have some movement in there but i had to hit mine with penetrating lube and use a pry bar before to get it to slide off the steering gear. i will have my truck back on wednesday so i will look at it more closely before ordering the u-joint.

 

Not really, but you bring up a good point. A collapsable lower shaft would be the "ideal" thing to do, and safer. Rag joint was really put in for vibration and did allow for a little flex, also allowing a good point to disconnect for repairs. I've never had a rag joint just "slip off". I did install a u-joint on my 66 conversion to PS, and chose not to weld in place, just drilled hole all the way thru and used bolts. Just a few more things to kick around in your head.

 

There's absoltely no reason to replace the rag joint with a universal. The rag joint will absorb vibration and will accomodate changes in distance between the steering collumn and steering box which happen with bumps and flex as the frame and cab are seperated by rubber body mount bushings. The rag joint does all this while costing absolute ZERO in lost steering motion .... and it's easy to service and they last so long.

You put a universal down there too on that 78 and you are going to beat the bearings in the steering collumn and feel all sorts of vibration and small hemmering in the steering wheel ... and it would not surprise me if one or both universals also failed earlier and they are NOT as easy to find replacements for .... nor as cheap.

 

If/when I start on my '77 I plan to swap over to ujoints. I honestly wouldnt use an aftermarket set up unless the joints could be bought at a parts house. I plan to use joints from semi trucks. Put a slip yoke in it to play it safe for the movement of the cab & call it good.

I even have a yoke/ujoint set up from some farm equipment I snagged years ago but want to go with something a little bigger.

I some what agree with tbear about replacing a rag joint but if its completely shot or your completely rebuilding the truck, why not?

 

I see no need to change to a U joint either, it cost me $7.00 to replace the rubber coupling on my truck. Found a generic Ford disc for it in the Help section of O'Reillys.

 

Did you confirm that the U Joint was in fact a 3/4"-36 spline?

 

There has been some discussion on this last few months

For example

https://www.ford-trucks.com/forums/1...l#post16677243

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