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Discussion Starter #1
Just did a search and found a recent post about rebuilding those nasty upper control arms. After having mine hot tanked, I found fatigue cracks in couple of spring perch holes. I made some "washers" out of 1/16" strap iron and tack welded them to the underside of the spring perch holes on the UCA. This will reinforce the fatigued holes and eliminate further cracking by providing a thicker base for the spring perch bolts.

Question I have is screwing those shaft bushing caps back on. The UCA threads are flattened, and I cross-threaded one of the bushing caps. I'm afraid I will have to "dull the threads" in the UCA again with a rat tail file and retry the procedure.

Is it proper to install them into the threaded shaft this way....so everything is centered? Screw in one bushing cap part way. Place the shaft in the UCA. Start threading the other cap so the shaft is now moving into both bushing caps. Turn the bushing caps in alternating fashion so the shaft screws into the bushing caps equally and remains centered in the UCA???

This is what I'm gathering from input from the other post. Just trying to verify the procedure.

Its easier said than done, but it looks like this thing is going to take several tries per UCA to come out right.
 

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Yup, you got it. It really shouldn't take a couple tries, though. The main thing is that the shaft is centered, and the bushings are tight. Just turn each bushing the same number of turns, holding the shaft centered and you're done.

I have to say, though, that with the fatique cracks, and the cross threading, I think I would have just gone for new arms. I guess it's not cost effective if you've already bought the parts, though. When I rebuilt my UCA's, I said never again. It's not worth the savings over brand new UCA's that are all put together.
 

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Consider this slight modification so you'll probably never have to rebuild again. It's from Mustang Steve's website:

Upper A-Frame Bushing Rebuild
When you remove the 3/4" nuts from inside the engine compartment, retrieve the alignment bushings from each of the 4 bolts (under the fender). Keep track of which ones went where and then put them back in their original locations when you reassemble. Tighten the 3/4" nuts very tight and they won't come loose. The real challenge is getting the new bushings screwed into place with the shaft centered exactly between the bushings and also not putting the bushings in a real tight bind by torqueing the large threaded bushing into the a-frame until it feels tight. The bushings will likely NOT tighten up in the a-frame without bending the sides of the a-frame towards each other. I tighten them until they are all the way in, but not necessarily tight. Then tack-weld every other flat on the hex of the bushing to the a-frame to keep them from backing out. IF YOU DON’T DO THAT, THE BUSHINGS WILL EITHER WEAR VERY RAPIDLY OR THE BUSHINGS WILL UNSCREW FROM THE ARM. (That is not a good thing). Before putting the bushings onto the shaft, take a die grinder with a 1/16" wide cutoff wheel and cut a groove from the end of the shaft, across the threads, cutting slightly deeper than the root diameter of the threads, then into the o-ring sealing area. Do this only on the BOTTOM of the shaft. If you check the physics of it all, that side is never loaded, so it won't cause any additional wear. Deburr the slotted area. That slot achieves two things. 1. It allows the grease to have a path so it can reach EVERY thread on the shaft. Without it, the grease you pump in with your grease gun only gets to the first couple of threads, leaving the rest to give a SQUUEEEEKKK every time you hit the speed bump pulling into the local cruise night. and 2: It gives the grease a pathway to leak (slightly) past the o-ring so it doesn't hydraulically blow out the o-ring when you set the car back on the ground as the threaded bushing turns on the shaft, decreasing the volume of the area where the incompressible grease resides. Nothing worse than watching your brand new o-ring come oozing out from inside the bushing when you lower the car. Before you let the car down, shoot the bushings full of grease, then remove all 4 zerk fittings. Let the car down slooowwwly and then bounce the front end up and down as much as you can. Now, reinstall the zerks and your bushings are properly greased with plenty of, but not too much, grease.
 
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I just love you guys that weld them on... glad I don't do front end work for a living anymore.
 

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My feelings exactly. Replace rather than rebuild UCA's. 50% of the time, the bushings strip in the UCA's before they get tight.
 

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Discussion Starter #7
Thanks guys. Had I known there were cracks in the UCA, I would have replaced them. The way I fixed them will cure the the problem though. Yes, I will have to tack weld bushings too. Thanks for the help. I'll let you know how this turns out.
 
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