Master Splines on Wormshaft and Coupling

[Cav73]

I am in process of cleaning and reassembling the steering coupler for my Challenger. I have a Steer and Gear power steering gearbox which I just bought a few years ago. It was in the car, and the column/coupler was attached to it, a year or so ago when I pulled out the steering column so I could rebuild my dash. The restoration shop that did the body on my car installed the column and apparently the gearbox/coupler connection was fine.

Background: The car is a 73 but the steering column and coupler came from a 71; however, I never had any trouble connecting the coupler and any gearbox before now (I had the 71 column in a 72 that I converted to power steering - that column went into this car as part of the resto).

Here is my question: I had trouble getting the column back into the car. The steering couple did not want to go on the worm gear shaft. Eventually I was able to coax it on part way, up to the gap for the roll pin. It would not go on further. I decided to pull it back out and clean and inspect the coupler, spring and shoes, which I did. However, I was surprised to see that the coupler does not seem to have an extra wide spline to match one I see on the worm gear shaft. I searched the site but I do not see something specific on this. Is the coupler supposed to have a wide "track" for the wide spline on the worm gear shaft? This coupler was definitely attached to the worm gear shaft for this box previously. I don't see any damage to the splines in the coupler, although the could use some additional cleanup with a bore brush. I did not count the splines in the coupler but I will do that tomorrow. I am wondering if there was some difference between years on these parts. Thanks!

 

[Challenger RTA]

Start with posting a picture of what you have. Splines of cup and shaft. There could be a manufacturing defect. There are some informed members here. Yes there should be a keyed area. When it was installed the first time it might have cut it's own splines.

There are two different couplers. Manual and power steering. Only difference. Over the decades. I do think there are about 6 different couplers mopar used on different models. Others may know better.

 

[Cav73]

Challenger RTA, thanks! I took these photos this morning. As far as I know, this is definitetly a power steering coupler because it came with this power steering column direct from an operational 71 power steering car. The owner and I traded columns; he wanted my manual set up and I wanted his power set up.

I did the best I could trying to get direct shots into the spline area of the coupler, clocking all around a couple of times for best chance at decent lighting.

 

[Cav73]

Worm gear photos

 

[Cav73]

Outside shots of coupler

 

[Cav73]

I tried hand fitting the coupler to the worm shaft to see if I could slide it on at all; it wasn't oiled at all. I couldn't really get it to connect. When the coupler was attached to the column, I was able to slide it as far forward as the roll pin gap. The column was oriented correctly under the dash. At the time, I figured that maybe the spring and shoes were not opening up enough to allow me to go further. I then took the column out rather than force it, and I figured I would properly mark the keyed splines - but can't find one on the coupler.

Thanks for looking.

 

[Cav73]

Also it was very hard to illuminate the splines in the coupler, so let me know if better photos are needed. I may have to figure something out for that. Regardless, at this point I cannot see a wider spline track that goes all the way to the bottom of the splined recess.

 

[Challenger RTA]

From what I recall from seeing the picture of the coupler. The key is where the notch is. It's more so the absence of one spline. Things I was looking for. Twisted splines form not being fully seated then used. To me they look ok. Rough or distorted splines from misaligned install and forced. Here again they look ok. As far as the pictures are good. There appears to be dirt or grime in the splines. I don't think there is, it's just the photo.
From have done this a few times. The spines are a very tight tolerance and fit. They need to be very clean and not use a heavy lube (grease) when installing. Use a light oil like 3-1 or very little anti seize.

I have installed a few. Before I would sand blast or take a pick and scrape the splines on both. Clean, blow out with brake cleaner or other. I have fix threads and splines of sort with a hacksaw blade, pick, nail, what ever works.

To install it should be bumped on with a hammer, not beat on! I'm sure Chrysler had a tool for it.

I want say it's not a press fit just a very tight tolerance. It takes tolerance to get it right.

 

[Cav73]

Cool, thank you. It sounds like I just needed to clean the splines - they were very dirty and covered by thick grease on the coupler and worm gear shaft. I actually thought the worm gear shaft went all the way through to the shoes and spring inside the coupler until I took everything apart. I consulted my 73 chassis manual last night and I see how it goes back together, plus there are great videos on that. But nothing showed the keyed splines very well. I will reassemble and try again as you recommend, aligning the notch on the coupler with the keyed spline on the worm gear. With light grease this time.