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Greetings all! They say that “Necessity is the mother of invention”. I have a Reatta that I recently picked up and the control arm rod was rusted off at the frame. I read every posting I could find on how to repair it and did a lot of research on my own. The solution I came up with is pictured below. Now I know that some of you are going to scream “Nooooooo!” but I did what I thought I had to do. I took careful measurements and cut the rod so that my completed work would be 10 5/8” from the control arm. I then cut about ¾” m20 2.5 threads on the rod (I used m20 because it was the closest to the diameter of the rod and cutting those threads was a “bear”). Then I screwed on a m20 hex coupler to which I screwed in a m20 to m12 adapter on the frame side. From there I was able to use a m12 threaded rod to complete the installation. I know that it is not original but I was looking for a reasonable cost solution. It seems to work fine, I will have to wait a while to see how it does on the long haul. There you have it, take it for what’s its worth.

2seater and Ronnie, thank you so much for your thoughts! I considered just welding a pipe or sleeve to the end but was unsure about the strength of just welds given the movement of the arm. I think both of you are right in putting some tack welds on it just to help relieve some of the pressure on the threads. I did weld the threaded adapter on the other end in place. Ronnie, no offense taken. With this being a critical support structure, it needs to be sound! As for the bend, it is an optical illusion because it is straight.

I think it has merit for sure. Was going to try something similar. I have a question about having threads on the top and bottom. Is that necessary? Maybe I am unfamiliar with the design, but was under the impression it just needed a gland nut at the top? Is that just for putting a bottom on the tube? If so, maybe welding a cap on the bottom might be less expensive than cutting threads?

I see a lot of potential. But for it to make sense I think it would need to be produced in quantity on a Mazak CNC or something similar. If you were going to do that you would want to buy all the parts needed and sell it as a strut ready to install. I think with the time involved to set up the part in your drawing in a lathe, turn it down to size and cut the threads is going to be really expensive to just make a couple of them at a time if you get a local machine shop to make them. It wouldn't hurt to ask since you know some machine shops you have worked with before.

Is it just the angle the photo was taken or is the coupler threaded on the rod a little crooked? If it is crooked I don't think it's likely to hurt anything, but it could put a lot of side load on the threads if you had to slam on the brakes in a panic stop. Just to be on the safe side I think I would tack weld it onto the rod if it's crooked, even if you have to take it to someone to do it.

Always…

I have a pair of lower arms, one with a broken end, and I was thinking of a welded repair. Somewhat similar to the threaded one shown, but just a plain welded sleeve with a threaded rod on the extension, probably stainless steel material. The only suggestion I can offer is either a jam nut on the coupler or perhaps a tack weld to prevent an possibility of rotation or push/pull on the new threads. Overall, I like the idea

I posted earlier hoping the Koni Cut-A-Strut inserts would be available, but no response from Koni and I am not seeing them anywhere. Shifted focus and going down the path of the Adjustable inserts from Koni. Using 6061-T6 tube, an insert carrier can be made such as below. The turned down OD will fit into the knuckle. The threads on each end will accept an M48 Koni Gland Nut. The design needs to be finalized based on the insert cartridge used plus I need to add the stabilizer bar attachment. Using a 2.25 OD x 1.75 ID (44.45 ID) gets us close to a 43.5mm OD of several inserts. A few questions. Does this have merit? Is there enough interest? If so, I can have these quoted up by a few machine shops that I use for work.

Update on the control system problem which pretty much confirms my previous post about the chip being bad or unable to communicate. Acting on Ryan's suggestion after receiving some new chips, I loaded the problem child S/C 1.4 tune on a new chip. After installing, the car started and ran perfectly. Going through diagnostics while the engine warmed up, everything looked normal. When it reached closed loop, there was a change in the sound of the engine, but it all went smoothly. I then shut down and installed the suspected problem chip and even though it started immediately, I could tell something was "off". Going to diagnostics showed "no ECM data" again, so I suspect it is running in a limp mode. According to Ryan, this means the ECM cannot communicate with the chip. All this chasing the tail of the real problem, looking in the wrong place and blaming the Memcal or the Moates adapter, was at least instructional although time consuming. Maybe I can iron out some of the small details before it is time for it to sleep for the winter.👍

Yeah, I zoomed in on the photo before I posted. That is the reason I said, "If you use some imagination you might think the rear tire is about to lift ". I just like to post photos of my car. 🙂