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Discussion Starter #1 (Edited)
Sorry in advance for linking to "non sponsors," although i don't know if that rule is still in place or enforced. Let me know and I will make the appropriate changes to the post. I just wanted to post the info so others can find the parts they need easily if they wish to undertake the project.

I've been messing around with this for a bit, wondering how effective this would be. Konnie the Goat had a thread a while back about using swedge tube and heim joints. However, i did want to to something much like the stock tie-rod end, and with a bushing on the other end.

The Cadillac Catera inner tie rod ends look like they are the closest to the type used in GTO toe link rods. The studs have the same taper and roughly the same diameter as the end on the stock toe links. They have a 3 degree taper, which through my brief search was very hard to find elsewhere. see post #8. OEM is a 7 deg taper stud. Most aftermarket tie rod end stud tapers are 7 or 10 degrees.

Gforce1320 says they use an AFCO tie rod, and from what I could gather the AFCO tie rods in the 5/8 size use a 7 degree taper. So, GForce1320 rod ends ether have a custom taper, or are using a 7 degree tapered stud in a 3 degree hole. Everything I have ever read says not to mismatch tapers like that since the stud could break. I've not heard of anyone ever having an issue with the Gforce1320 rods, though... so who knows. see post #8. OEM is a 7 deg taper stud. The Gforce1320 toe links I have are an early version. The tie rod ends are stamped federal mogul. I haven't removed them for inspection to find out the stud taper or thread size.

Having settled on the Catera ends, the threads are M14 x 1.5. Just about every swedge tube or tube end I could find were SAE thread, or if they were metric, they were not this size. However, I was able to locate steel swedge (swaged?) tube that uses this thread pattern, mostly for VW dune buggy use (reminds me of all the times I did research on CV joints for this car...) However, they don't really sell a length that would work for what I needed. Closest would have been a 10” tube.

Pacific Customs: 14mm x 1.5 VW Threaded Tie Rods and Dune Buggy Parts, Sandrail Parts, VW Parts

A & A Manufacturing out of Michigan does make tube ends with this thread size, that uses a 1” ID and 1.25” OD. It should fits 1.25” OD x .120” wall tubing with just a little clearance. The ends are mild steel, at least from what their site claims.

AA-613-A Threaded Tube End, Fits 1" ID Tubing, M14 X 1.5mm Thread (RH)

AA-613-B Threaded Tube End, Fits 1" ID Tubing, M14 x 1.5MM Thread (LH)

A & A also carries tube ends in other sizes in plain steel, so you can go that route instead of chromoly.

If you want to go with 100% chromoly rod and ends with the M14-1.5 threaded tie rod, you will probably have to drill and tap a chromoly tube end. I was warned against doing this, but decided to try it anyhow. I was able to successfully drill and tap two 4130 1/2-20 tube ends, but the end result was not to my liking and it was a major pain. Not only is it hard to locate taps made of hard enough steel to do the job, it's difficult to do with accuracy. Not easy to cut--even though I tried making my initial holes as centered as possible, the tap had other plans. The threads ended up also fitting a little looser than the A&A M14 x 1.5 tube ends I purchased. IMHO this isn't worth doing for the amateur, though I'm sure a machine shop may oblige for the $$$.

You can mix chromoly and mild steel as well, if you want to try this. It is possible to weld the two together via the correct TIG process, and this is the route I took. I am using the A&A steel metric ends, 1.25” x .120” 4130 CR tubing and 4130 CR 5/8-18 tube ends on the opposite side. The Allstar 5/8-18 left-hand-thread 1.25” x .120 wall tube end has a hex face machined into the body, so this could help with adjustments on the car. I did not know this previous to ordering, otherwise I would have gone with two leftie 5/8 ends and two righty M14 ends. I am satisfied using a rubber strap wrench, though, so there is that.

Now, for the end that replaces the stock bushing. Speedway motors carries four-bar ends that are poly bushed that may work in place of a heim joint. So do a few other places on ebay, if you search, but it is usually a larger size than 5/8ths. I know I had issues with putting in a toe link setup that uses heim joints in a daily that sees winters and a lot of dirt and nasty roads. This could definitely be an alternative, especially if you are using a tie rod on the other end.


I am going with a heim joint, and am using a heim joint boot. One of the main reasons is that i know i can get them in CR and they should be stiffer than a polyurethane 4-bar end, and can articulate. If that doesn't work out well I may swap out for a 4-bar link.

I went with QA1 heim joints, with SEALS-IT boots. They carry a few sizes, I imagine if you get a set of Spohn or Gforce1320 links, you could find the correct size to fit over their boots as well. They are a major pain to slip on, but fit tight and should help keep dirt and moisture away form the joint. We'll see how they turn out.

The inexpensive route would be to go all mild steel. Not as stiff as chromoly, but probably still stiffer than stock, and cheaper than replacing them with new parts. The A & A manufacturing ends are inexpensive, decent 1.25” x .120 wall tubing is also not that expensive. Most of the cost would be in the heim or 4-bar rod ends and tie rod ends. If you welded them yourself, you would end up spending a lot less than for a set of premade ones.
 

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They look nice. I swapped out my G-Force ones for Spohn ones because the Spohn ones have an adjuster in the middle instead of at the ends. When installed, the G-Force ones couldn't be adjusted without taking them loose from the frame or control arm. But others have said they could do G-Force adjustments on the car, but I sure couldn't, I couldn't get a wrench on the lock nuts at one end (the frame end I believe).
 

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Discussion Starter #6 (Edited)
I have a suspicion the online calculator i used for the stud taper is wrong somehow.

I am going to remeasure and calculate it by hand tonight when i get home. I have a suspicion the stock stud taper is actually 7 degrees.

If that's the case, there are a lot of readily available tie rod ends out there that will work with an SAE threaded tube end.

FWIW the calculation should be ((large end dia)-(small end dia))/(length of flute), then take the arctangent of the result. Correct me if this is wrong.

A few calculators are giving me different answers, and i don't remember the measurements i took.
 

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Discussion Starter #7
They look nice. I swapped out my G-Force ones for Spohn ones because the Spohn ones have an adjuster in the middle instead of at the ends. When installed, the G-Force ones couldn't be adjusted without taking them loose from the frame or control arm. But others have said they could do G-Force adjustments on the car, but I sure couldn't, I couldn't get a wrench on the lock nuts at one end (the frame end I believe).
Looks like the spohns are 4130CR tubing as well. The GForce1320 say DOM, which is generally a mild steel alloy, iirc.
 

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Discussion Starter #8 (Edited)
OK this is what i get for not being thorough and trying to take the easy way.

Made a spreadsheet, input my measurements, and it says the taper for the stock toe rod stud and the catera tie rod stud is 7 degrees.

502448


the 5/8-18 AFCO tie rods i was able to find was also listed a 7 degree taper stud, which should work. 30238 and 30239. The large/small taper is listed as .590"/.500" so it could fit quite nicely.

dclaw_fantum also mentioned that his Spohn links use Proforged 104-10162/104-10163 tie rod ends, which cross reference to the inner/outer tie rod ends for a C3 corvette (and some obscure single year model of a chevy van). These also use a 5/8-18 thread, and i would imagine the stud taper to be the same common 7 degree.

This makes so much more sense. 7 and 10 degree tapers seem the most common for automotive tie rod and ball joint studs.

hopefully the DIY'er can use the above large/small dia measurements to source their own tie rod ends. i'll pick up a pair of afco 30238 and 30239's as well as the proforged pair soon to measure.

From what i gather the proforged does use a larger threaded stud, 1/2-20. they obviously still fit the GTO, though.
 
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