Making a hybrid steering U-joint (Miata/Mopar content)

I'm working on the steering system for my Midlana build. The car uses a Miata steering rack, and therefore a Miata lower U-joint. I'm hoping to use the intermediate shaft that I have laying around from my engine donor, a Dodge SRT-4...it just happens to be about the right size and is collapsible and telescoping. Unfortunately the Dodge u-joint splines don't fit the Miata rack and the u-joint is one piece with the shaft. Luckily both the Miata and Dodge u-joints seem to use the same size center section. Both joints are also held together in the same way: 4 stamped in indents. I'm wondering if anyone knows how I could go about taking this type of u-joint so I can combine them into a hybrid piece that will fit my project.

The black joint is from the Miata, bare metal is the Dodge intermediate shaft. You can see the indents on the Dodge piece. I tried grinding down the indents on the Dodge joint with a dremel and beating on it with a hammer, but it didn't budge.

Thanks!

Salvaging the u-joint is going to be tough. What about getting a third joint and surgically cutting the joint out so you have a pristine u-joint. Set the clean u-joint aside.

You can then hack the u-joints out of the Miata and the Dodge yokes, clean up the yokes and install the clean U-joint for a perfect hybrid.

Cut the yoke at the red line so the u-joint is not damaged.

Got a shop press? 20 tons should overcome those punch marks no problem.

How different are they in dimension? They make conversion U joints for drivelines, I am sure they make them for steering. Have you checked?

I was able to rebuild the u-joints in my mini without a hydraulic press. They used circlips to hold everything together and not punch marks. Never tried to take apart one that wasn't meant to be taken apart.

John twist does u-joints with a vice and a hammer.

(fun, but mostly unrelated video: https://www.youtube.com/watch?v=gDX17xf9grA)

Thanks for the suggestions. The main issue is that they aren't meant to be taken apart. The u-joints are very close in size j within a few thousandths. I need to get them apart without damaging the lower Miata yoke or the upper dodge yoke and one of the u joints. I'll try the press tonight, and resort to fujioko's destructive method if that doesn't work. Worst case I can make my own intermediate shaft.

You're saying that you can't get the joint out of either piece? Sorry, then I surely misunderstood.

With GMs driveline U joints for a while, there was a plastic thing which prevented the joint from separating until you melted out. Are you sure there is nothing like that going on?

In reply to tuna55:

That's step one, getting them apart. They aren't intended to be disassembled, and use 4 dimples in each side of the yoke to hold the joint in place. I have ground these down, but it still won't come apart with the gentle persuasion of a hammer. I'll try more force and report back.

Another idea.

Assuming the mopar shaft is hollow, it looks like you could cut the yoke off the mopar shaft, cut the miata u joint at the clamp, slide it in the mopar tube and weld it up.

Maybe...I'm not sure if the miata yoke material is weldable, and the dodge shaft seems to have some sort of rubber coating where it's lower u joint is attached.

Those joints are not meant to come apart. If you get the stake features removed, you will probably have to pry the caps out- there may be a step in the bore of the yoke that prevents the cap from going through the yoke. If you get them apart, they most likely won't be able to be mated together- the lower yoke from the Miata to the upper yoke from the Dodge.

I assume you will need two universals in your steering shaft so why not use the Miata joint at the rack and the Dodge farther up the steering shaft. Cut the shaft above the lower universal and mate the upper part of the Dodge shaft there. Those yokes appear to be steel- maybe forged or cast steel but you should be able to weld to them.

Well pressing the u joint out damaged the joint but left the yoke intact. I think I might be able to make it work with the destructive disassemble method, but don't want to be out a $30 (eBay) Miata u joint if it doesn't work.

I will probably end up making my own intermediate shaft. I need to hit the junkyard to find a shaft with splines that fit the Miata joint. If I can find another cheap Miata lower joint in the yard I may still give it a try.

Is the Mopar intermediate shaft hollow?

If it is, maybe just the bottom yoke off of it, drill holes in the stub that's left, slide in a short length of the correct OD pipe or better yet a short length of splined shaft from a Miata, plug weld that pipe in place through the holes that were drilled in the intermediate shaft stub and slide on the short Miata piece as usual.

Onto the splines and tighten with the attached clamp/bolt.

Maybe?

As you found out you're going to sacrifice one of the ujoints. I did something similar in my van to make my stock column work with the older manual rack I was using.

I hit the junkyard and got a shaft with some splines that fit the Miata u-joint from an 87 Mazda 323 wagon. I need my steering wheel to get here so that I can set its position, and the position of the upper shaft, then I will splice the 323 and neon shafts together.

Whoa. DON'T USE EXCESSIVE FORCE PRESSING THEM OUT YOU WILL BEND THE YOKE AND THEN THEY WILL BE OUT OF ALIGNMENT. These do come apart they are meant to be rebuilt you just have to know what you are doing.

I have a side business rebuilding intermediate shafts for 944s. It is easy process if you know what you are doing. BUT IT CAN BE VERY DANGEROUS if you get it wrong. This is after all what allows you to steer the car. Drop me an email or a pm and I will send you my cell # and I can walk you through it.

This is me. My site for rebuilding the shafts for 944s.

http://www.emotorsports.org/prod02.htm

I outline the rebuilding process on the page but obviously I don't give away the farm either. I will gladly help. Hell if you sent them to me I can do it as long as the u joints I have in stock fit. You can not re use the old u joints. They are destroyed in the removal process.

in short we should talk.

The stock car places have alsorts of messed up joints available. This guy had some strange ones i need for chevy / mopar swap but that was 20+ years ago...... Krazy Korlacki Speed Equip 462 Winthrop St, Rehoboth, MA 02769 (508) 252-6830

"Krazy Korlacki Speed Equip 462 Winthrop St, Rehoboth, MA 02769 (508) 252-6830"

Remember him ? ! ? ! ? ! ?

He had a little of everything back then and could get you more of it if you wanted. My buddy Todd used to get me out of the house every once and again and we'd hit there on occasion then on to the magazine stand in the mini-mall opposite the Triumph Motorcycle dealer. Great selection of British car magazines.