Did I bend my banana bracket?

[skidd]

I finally found the cause of a strange vibration that started after doing a break-stand and then a mediocre launch (@TMartinLVNV was there, wasn't anything spectcular). And these 315 Nitto G2s I don't think even have fantastic grip.
Anyway.. somehow my axle had pivoted up quite a bit. Causing the ujoint phase to go way wacky. Hence.. the vibration.
I had found that I had a whimpy 5/16" bolt holding the lower banana bracket to the pumkin. I remember how that I didn't have the 1/2" I needed, so I thew in what I had, and forgot to replace it. oops. It was a bit bent now.
I just figured it bent the bolt, and slipped on the tube.
But.. the more I fussed with it, the more I found I couldn't get it back lined up. Nor, could I adjust the swedge tube enough to bring the axle down far enough.
So.. did I bend my lower bracket? I think I might have. I can't remember exactly how this looked originally.. but.. this looks a little suspicious to me.
My neighbor has a pretty nice welding setup and says he can put a few welds on there easily. So, I'm guessing I'm just going to cut off the lower bracket and weld the banana bracket to the axle.

https://www.ludicrous-speed.com/zp/zp-core/i.php?a=Shanes%20Cobra/misc&i=PXL_20210124_174853553.jpg&s=595&cw=0&ch=0&q=85&wmk=%21&check=3731ef36be9c91a4a013f0c739d2225b9d991b32

https://www.ludicrous-speed.com/zp/zp-core/i.php?a=Shanes%20Cobra/misc&i=PXL_20210124_174909489.jpg&s=595&cw=0&ch=0&q=85&wmk=%21&check=3731ef36be9c91a4a013f0c739d2225b9d991b32

https://www.ludicrous-speed.com/zp/zp-core/i.php?a=Shanes%20Cobra/misc&i=PXL_20210124_174932510.jpg&s=595&cw=0&ch=0&q=85&wmk=%21&check=3731ef36be9c91a4a013f0c739d2225b9d991b32

This crack in the powder coat is pretty telling.
https://www.ludicrous-speed.com/zp/zp-core/i.php?a=Shanes%20Cobra/misc&i=PXL_20210124_180751985.jpg&s=595&cw=0&ch=0&q=85&wmk=%21&check=3731ef36be9c91a4a013f0c739d2225b9d991b32

[D Stand]

Looks bent to me. Was the 5/16 bolt still in tack when taking it apart? If yes, then it did it’s job and the bracket itself is the weak link. I think this is why guys will install as directed but then weld it as well to the axle tube. I would straighten it and have your neighbor weld in some gussets to make the bracket stronger. Where the bolts that clamp the bracket to the axle tube tight when you took it apart?

[skidd]

Yeah.. the more I find pics of the banana bracket online, the more I'm sure it is indeed bent.
The main bolts were tight. Though.. I gotta say.. perhaps not tight enough. They broke loose without needing an extension on the ratchet handle. I wonder if the smoothness of the powder coating didn't help much to keep a good grip on the axle tube?
The 5/16 was still intact. Just a bit bent. OHyeah.. but the washer was squashed and half pulled into the hole big-time!

[NAZ]

That'll buff-out.

Seriously, welding the UCA axle bracket is much better than clamping one on the axle tube but a couple of tips: take all the weight off the axle before you start welding and if you will be welding to the cast steel center section, find a pro with experience. The best practice for welding cast requires a cumbersome process short welds, stress relieving between, temp control, and uses TIG with Ni-rod filler. Expensive and time consuming but gives the best result. I use a jig to do this so I don't end up with a warped axle. And you'll need proper lateral bracing to prevent it from bending. I'd also advise you to fab a new bracket and toss that one in the scrap steel pile.

[Big Blocker]

definitely bent . . . FWIW, there are NO "twisted" parts in the rear suspension from the factory.

Doc

[RoadRacer]

Curious, did you have a vintage performance "banana bracket brace kit" installed?

Here's mine:141346

[skidd]

The new factory five banana bracket comes with a arm that stretches from the bottom to the pumpkin. Hard to explain. Supposed to do the same job as at VP bracket. I'm leaning a bit now towards makeshifting my own VP style arm.

[RoadRacer]

The new factory five banana bracket comes with a arm that stretches from the bottom to the pumpkin. Hard to explain. Supposed to do the same job as at VP bracket. I'm leaning a bit now towards makeshifting my own VP style arm.

Mine from 2017 had that too, unless it really is a new design. But that doesn't support/strengthen the top of the brace. I wish I'd got mine welded one too - the more strength on this thing the better :D

141350

[NAZ]

Fabricate your own and add extra adjustment holes, at least one above and one below the original at 1" centers. Then you can adjust your anti-squat and help hook the tires. If you look at some of the race part suppliers you can purchase these type brackets ready to weld onto your axle. Rollin' your own allows adding adjustability to your suspension that FFR didn't design in. What you got with your kit didn't work -- now go make it better. That's the basic premise of hot rodding, make it better, faster, stronger, cooler.

[CraigS]

Ages ago my friend cracked his banana at an autocross. So I decided mine needed strengthening. First I added boxing on the front and rear parts and around the bottom where yours is twisted. Then I added a tubular brace. I liked the VPM brace but using all the nice rod ends made it expensive. So I made mine in place so there would be no need to make it adjustable.
https://live.staticflickr.com/65535/48119719273_523045968b_z.jpg (https://flic.kr/p/2gjb95i)IMG_20150902_141638084 (https://flic.kr/p/2gjb95i) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr

[GoDadGo]

Steve's Stupid Question:

Is it just the bolt-on Banana Brackets that tend to fail?

[skidd]

Thanks for that Craig... I'm looking at doing something similar to yours. I'm being a super-cheap-skate around using VP heim joints too. Plus.. I love building stuff!!!
I still have the upper control arm ears on my pumpkin.
My current plan is to weld a small heavy-gauge steel bracket to the control arm ear. And then run a piece of angle steel from it to the side of the banana bracket. Held with a couple of good quality 1/2" bolts.
That way.. at least if in the future I find that I need to replace this bracket. Or.. as NAS suggested.. fab my own. It won't be welded to the tube, so easy removal. And the only welding will be on those useless ears.
To be honest. I'm a little surprised at where my bracket failed. That square tube was still perfectly straight. Just the bottom wings bent under the stress. Too late now obviously, but fully boxing in the bottom might have prevented this.
Oh.. yeah.. and I thinking getting some better quality bracket bolts (like Crag has), and torquing the snot out of them should help too. I ground out the powder coating from the inside of the bracket, and ground off any paint from the axle tube. Hoping for better grip.

@GoDadGo. .. I think it only happens to the Ford powered roadsters.. too much torque. ;)
.. sorry.. couldn't resist..
My guess is that my failure was imply that the bracket was not torqued on quite enough. Putting too much stress on that bottom arm by itself.

[TMartinLVNV]

I think that it was because you did a burnout with my fat *** in the passenger seat :rolleyes: Your car was not used to overcoming the extra mass I added.

[NAZ]

If your T-5 has a 3.35:1 1st gear and your final drive is 3.55:1 and you have a modest 400 lb ft of torque; that UCA bracket is subjected to 4,757 lb ft of torque. Rev the snot out of it and drop the clutch, you get a big shock load so brace it like you mean it if you want it to last. Then go drive it like you stole it:)

[skidd]

Guess it's a good thing I have the 2.95 1st gear T5z. :)

[RoadRacer]

@GoDadGo. .. I think it only happens to the Ford powered roadsters.. too much torque. ;)
.. sorry.. couldn't resist..

LOL. Don't poke the bear!

[Avalanche325]

I have a banana bracket in my garage. Let me know if you need it.....shipping cost only.

[frankb]

Skidd:

Back when I started 8317, I was skeptical of the bolt-on banana bracket, both in terms of strength and attachment. So, I boxed mine both front and back sides, had the axle tubes welded to the center section (it is cast STEEL), and welded the bracket to the axle tube. No more worries! Since I had it out of the car for a rebuild, I had the whole thing black powder coated just for looks!141430141431

[GoDadGo]

I think the bolt-on banana bracket is problematic.
Welding it to the axle will likely solve the problem.
After following this thread, I'm glad Moser welds them.

[j.miller]

I bent my "Banana Bracket" on prom night 1977......I got better. WHAT ! Jus sayin....da Bat

[CraigS]

I thought about welding mine to the axle but decided against it. Not real sure what to use to weld it to the casting, fearful of bending the tube welding it there. So decided to make braces where all the welding is on removeable parts. I fitted the pieces together on the axle and tack welded them. Removed the brace and finished the welds. BTW, I had forgotten that there is a brace running over the the ear for the right 4 link bracket. That ear had to be partially removed to run the tube brace. When I got the tube brace on, I was concerned that the angle it runs at in top view could try to push the top of the banana sideways. The brace to the 4 link ear solved that. If you zoom in on the pic you can barely see it. It is made from 1 inch square tubing.

[GoDadGo]

I bent my "Banana Bracket" on prom night 1977......I got better. WHAT ! Jus sayin....da Bat

I wasn't as lucky for my prom, which was in 1981, but that's okay.

[skidd]

@Avalanche325. Thanks for the offer.. I'll let ya know. I'm going to brace this one first, and see how it goes. If it fails, I'll hit ya up on that offer for sure.
@Craig Ah. yep. I see it back there now. That's closer to how I was planning to setup my brace. A bit more aligned with the bracket, and a bit more straight. Like you, I'm a little cautious about welding to the tube. I might just run a small 1" bead on one side though. Easy to cut off if I really need to.
@Miller.. as soon as I saw you had replied.. and I re-read the thread title.. I knew I had lobbed that soft-ball for an easy wack of da Bat ;)

[FFinisher]

Yea you bent it.


There are thousands out there that are bolted on. One failure does not mean this is a bad set up. They work.

Think maybe a bolt bigger than 5/16 might be in order . This was probably the root cause.... but that’s just a guess.

Pretty sure airplane wings would fall off if they were held on with a 5/16 bolt.

[skidd]

I think this'll hold. A piece of 3"x2"x3/16" Angle Iron welded to the top control arm ear. With a piece welded to the top and a 1/2" hole drilled.
Then, a a piece of 1.5"x3/16" angle iron from the bracket to the side of the banana bracket. Both bolted with a nice 1/2" Grade8 bolt.
Axle tube cleaned up a bit and roughed up to try and get a better bite with the banana bracket.
And voila!! Everything lines back up again.


https://www.ludicrous-speed.com/zp/cache/Shanes%20Cobra/misc/PXL_20210131_154441505_595.jpg?cached=1612111163

https://www.ludicrous-speed.com/zp/cache/Shanes%20Cobra/misc/PXL_20210131_154621666_595.jpg?cached=1612111392

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https://www.ludicrous-speed.com/zp/cache/Shanes%20Cobra/misc/PXL_20210130_194106819_595.jpg?cached=1612111467

[CraigS]

I think so too. What did you use to weld the bracket to the diff casting?

[skidd]

Used my 220v Miller Stick Welder, and a few 3/32 6011 rods. Did a nice enough job, for my mediocre welding skills, and the contortionist I had to channel to get my head and arms into a position to weld. I didn't fully drop the axle to weld it in, just lowered it enough to crawl in. In hind sight, dropping might have been worth the extra effort, but .. oh well.

[Norm B]

A high nickel welding rod would have made your life easier welding on the cast steel differential. As a farm kid, I have welded pump housings, exhaust manifolds and even an engine block with Nirod. Makes a strong machinable weld.

Norm