Trailing arm re-tap options

[cammacmillan]

Once again proving nothing is straight-forward....

Plan was to clean up the TAs and have a local machine shop tap to 3/8 unc and install a step stud to keep the 5/16 on the hub attachment....BUT

Removing the corroded/stuck studs, seems most were helicoiled at some point in the past (can't be recent given the state of them). Helicoils are maintaining the existing 5/16 unf studs.

What are my options now? Am I right in thinking the hole for the helicoil is already larger than the hole would be to tap to 3/8?

Am I tapping to a 3/8 helicoil? Dilling/tapping to a keensert?

[Atl TR6]

removed three helicoils when installing keenserts in all TA holes.... see picture....two were UNF and one was UNC

In the second picture, the hole at 8 o'clock before keensert was inserted had the UNC helicoil.... nice clean threads waiting for the keensert.

[cammacmillan]

Hi Bruce - looks like a little bit of everything there! Did you just drill out the helicoils?...and did you use the Patton jig? Part of me thinks I should have left it alone but there was no sign they'd been repaired. At this point I think most were helicoiled and I think I'm probably keenserting them now.

[Litespud]

IIRC I replaced the helicoils in my TAs using Keenserts equivalents from McMaster (#92070A250). These were steel locking inserts, 7/16” UNC on the outside (so wide enough to get clean metal for the new tapping), 5/16” UNF on the inside, so using standard studs. Locking so the inserts won’t back out - not cheap (~$2.50 ea) but way better than helicoils IMO

[Atl TR6]

Hi Bruce - looks like a little bit of everything there! Did you just drill out the helicoils?...and did you use the Patton jig? Part of me thinks I should have left it alone but there was no sign they'd been repaired. At this point I think most were helicoiled and I think I'm probably keenserting them now.

used Patton jig. followed his directions to the "T" Ordered his recommended supplies from McMaster.

If you go this route, put all studs back in and make sure jig fits, rotating the jig around to next stud to ensure the three small holes all locate as in picture

To pull a helicoil out, I used a sharp tip to pry it from side of hole so i could grab with a needle nose plier.... than just twist and pull and you will end up with a long stretched helicoil.
Remember you need three studs in place to fit the the jig

[A Brit in Bama]

Couple of years ago, when I installed Good Parts rear hubs, I thought I'd take the opportunity to use Keenserts. I used Rick Patton's jig for the drilling process (which Litespud kindly lent me, as I recall).

When drilling the existing holes, I found that three holes in one TA already had Helicoils in them - I had no idea the were there previously. They just came out with the rest of the swarf when drilling the bigger holes with the X-drill supplied in the Patton kit.

Note I am not recommending this as an approach for removal of the Helicoils - I can't say for certain that you'd get as lucky as I did in getting them out so easily.

[Anthony]

When I bought my Rat-co steering wheel I think I saw that they were developing replacement T/A's. No idea of the cost or availability.

[A Brit in Bama]

When I bought my Rat-co steering wheel I think I saw that they were developing replacement T/A's. No idea of the cost or availability.

Yep...been lusting over a pair for a while... But at $600 per side, I think I can live with the originals...

https://www.rat-co.com/tr-4a-5-250-6...ng-arm-project

[TRick6]

Ratco productions; whats not to love. Any news as to the weight of the new steel vs. the old aluminum trailing arms?

[UberXY]

I’m hoping someday Ratco makes front tubular a arms with rod ends for adjustment.

[BobbyD75TR6]

I’m hoping someday Ratco makes front tubular a arms with rod ends for adjustment.

A few years back he was considering camber adjustable tubular TAs with inboard disk brakes....

[A Brit in Bama]

I’m hoping someday Ratco makes front tubular a arms with rod ends for adjustment.

Bit like these? A forum member (can't remember his handle right now) made these. I thought they were intriguing, so kept a pic. I believe I discussed this concept with a manufacturer (possibly Richard Good) a few years ago, but whoever it was didn't think it would be economical.

(cammacmillan - apologies for the hijacking of your thread!)

[cammacmillan]

A Brit in Bama - hijack away!! I've had my head buried in finishing up the projects for this round and getting the wheels back on. I picked up Rick Patton's jig and felt like an allstar drilling and tapping the TAs - turned out great though...keenserted up and back on the car with some Philtr6 rebuilt hubs now.