Rag joint - aren't there supposed to be splines all the way around?

[73MustangCoupe]

I am cleaning up my steering column in preparation for reassembly.  The rag joint was pretty dirty, no surprise there, but when cleaning it up, I found that only about 1/3 of the circumference of the portion that attaches to the steering box had any splines on it.  The rest, it appears is stripped?  I am thinking it should have splines all the way around the inside.  I think you can see in the picture that it looks like only 1/3 has splines and the rest appears shaved or something.  I've got a ton of money in this build and it won't break the bank, but I was hoping this was one part I could reuse.  I'd sure appreciate your thoughts on it.

 

[Carolina_Mountain_Mustangs]

Yes I think all the way around. Will look tomorrow. BTW you can get new rag joint rubber at the help rack at most parts stores. I got the bolt kit at NAPA.

 

[OMS]

That is normal they do not have full splines

 

[Stanglover]

This is the shaft on a Saginaw 800 PS box typical on Mustangs with power steering. The flat matches with the coupler.  I'm not sure about a manual box shaft without digging my old one out of the old parts box. 

If you want to buy a complete coupler, you'll need the Lares 201 for a non tilt column. Buy from RockAuto.com, way cheaper.

 

[73MustangCoupe]

Thanks!  That is what I needed to know. 

 

[73MustangCoupe]

Well, I got a bright idea, so while waiting for body filler to set up on the Rickster, I grabbed the old coupler and tried to fit it to the rebuilt steering box.  Wouldn't fit.  I checked with Red Head Steering Gears, and the confirmed that the steering box is a 13/16 shaft with 36 splines.  So I will have to replace the lower half of that coupler with one that fits.  Shouldn't be hard to find, but one more hoop to jump through.  

 

[Bentworker]

That makes no sense that your old coupler didn’t fit your new box.  Was the coupler too big?

 

[Stanglover]

As mentioned, the Lares 201 is the correct coupler size and spline wise. the only difference is that the two "safety" posts are the same diameter, but are the correct length. The Scott Drake POS has the post with the original diameters, BUT are far too short to engage in the slots on a NON TILT column. The post are there for safety should the rubber fail, not for steering as some think. 

I think that 36 splines would be correct if there was not the flat. Looking at my pic, the 5 (extra) splines would be about the same width as the flat. Lares 201 is listed as 13/16" 31 spline. This what I have and use on my car.

EDIT: I just counted the splines on a spare shaft and it is 31 splines excluding the flat, so if no flat, it would be 36. Hope that makes sense.

 

[Carolina_Mountain_Mustangs]

If that is the box you bought from me that did not have tilt I do not think. I have the coupler will check tomorrow I think it was just fixed column.

 

[73MustangCoupe]

David, the steering box was rebuilt at Red Head Steering Gear, and they confirmed the input shaft is 13/16" in diameter and had 36 splines.  I don't know what was original, but the rag joint on the steering column doesn't fit the 13/16" input shaft.  

Stanglover, thanks for taking the time to double check the steering gear.  It appears that there is confusion in how splines are counted.  From what I have found, if there is a flat milled into the shaft, then half the splines are counted and then doubled to get the number of splines for the unmilled shaft.  It makes sense that the flat milled into the shaft would eliminate about 5 splines, so I believe that the Lares 201 is probably the correct rag joint.  Thanks, Stanglover.  

 

[Stanglover]

David, the steering box was rebuilt at Red Head Steering Gear, and they confirmed the input shaft is 13/16" in diameter and had 36 splines.  I don't know what was original, but the rag joint on the steering column doesn't fit the 13/16" input shaft.  

Stanglover, thanks for taking the time to double check the steering gear.  It appears that there is confusion in how splines are counted.  From what I have found, if there is a flat milled into the shaft, then half the splines are counted and then doubled to get the number of splines for the unmilled shaft.  It makes sense that the flat milled into the shaft would eliminate about 5 splines, so I believe that the Lares 201 is probably the correct rag joint.  Thanks, Stanglover.  

Ron, I glad you were able to clear that up in your mind. Things like that sure gets us confused.................. and that isn't hard these days! I also verified that the manual non power steering box input shaft is 3/4", full round, but as the old rag joint is still well and truly attached, I was not able to count the splines, but it is listed on R/A as 3/4" 36 spline.

All the best with it moving forward.