twisted axle tube today

Looks like I'm welding mine before any track duty.

this is probably a dumb question, but can the tubes be welded up while still on the car? or without dis-assembly of the housing?

Im leaving mine and risking it. If the rear ever comes out ill do it then.


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rojizostang said:

this is probably a dumb question, but can the tubes be welded up while still on the car? or without dis-assembly of the housing?

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Yes. It's not as easy, and maybe not as precise, but there have been some guys who have done it that way with success.

okay, thanks.

Welding is going to do little to add strength. Need to pin it.

Welding will absolutely take care of the problem. The only reason it wouldn't is if the welds were crap.

do the 05-09 GT's have this issue too? just wondering if I should think about welding my axle tubes on my 07 gt

This^

Nice one. Not as rare as you guys seem to think though. Welding up the outer tubes on an 8.8 axle to keep this very thing from happening is a common mod. People been doing this going back to the old Fox bodies. Ford has never welded the outer tubes to the center housing on the factory 8.8's

Just goes to show that it is not a silly mod either. I had them weld mine up when I took it in to have my BMR subframes welded in.

C-clip eliminator mod is also a good one to do, but you really got to be trying hard to break the stock 31 spline S197 rear axle

Tons of people get away without welding these. It's a chance you take that you're one of the unlucky ones if it breaks.

cschoening09 said:

do the 05-09 GT's have this issue too? just wondering if I should think about welding my axle tubes on my 07 gt

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yes its the same rear axel...you put power to the ground you risk twisting

I got mine welded by Dustin (CPRsm).

He did it on the car.

He was priced well, and is an awesome dude, but more importantly he does killer work.

Thekid760 said:

I got mine welded by Dustin (CPRsm).

He did it on the car.

He was priced well, and is an awesome dude, but more importantly he does killer work.

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I've worked with tons of welders... but that is a beautiful weld.

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19COBRA93 said:

Welding will absolutely take care of the problem. The only reason it wouldn't is if the welds were crap.

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Ahhh... here we go again...




here is my .02 and some pics of how it should be done.











The bolts are Grade 8 and they are put in direct shear with the tubes. It takes an enormous amount of pressure to strip these in direct shear.

In contrast you can weld the tubes and put this thing in the jig and i can put less than 30 psi of pressure on it and snap the welds. AND yes it doesnt matter how nicely the weld is done it will snap because the cast is just that weak, and weaker when you melt it and reform it in a weld.

Its hard to tell racers this because you get the " well so and so runs 5s with his welded and he has no problems." Its the factory pins holding the car. The weld holds absolutely nothing. I have seen countless welded tubes in the jig and have yet to get one straight without breaking the welds. Welding presents a few other problems as well, if not completely done right and its difficult, you can melt the seals where the tubes slide in and cause leaking by the tubes(seen it), also it pulls the axle and its no longer straight(seen some examples of this and wonder how the car ever went straight down track). IF we weld the tubes we cant weld them and then straighten, because it will break the cast pumpkin. IT has to be welded in the jig and straighten as you go to get it right, its a very time consuming process and its pointless. If the pined tubes wont work you have a 3 second capable 1/4 mile car that needs a 9 inch housing at that point.

The tubes are "connected" with the pumpkin. Thus it provide a stronger connection as it takes alot of pressure (PSI) to shear the grade 8 bolts off. The pumpkin and axle tubes are drilled and then tapped for the bolt (with sealant) this locks the tube inside of the pump vs on the edges only. There are no nuts on the inside, the bolt is just flush with the ID of the axle tube. Since the connection is more inward toward the "meat" of the pumpkin it is stronger and forces of shear and leverage won't have effect on it, compare to putting a small bead on the outside edge where axle tube and pumpkin meat at.

Interesting. So what is the magic length of bolt that will go through the pumpkin casting and axle tube, but not interfere with the axle itself? I'm guessing it's pretty tight tolerances there.

I'm also guessing the only way to run a tap all the way through is with the axle completely removed. Kinda puts a damper on this being a weekend job.

46Tbird said:

Interesting. So what is the magic length of bolt that will go through the pumpkin casting and axle tube, but not interfere with the axle itself? I'm guessing it's pretty tight tolerances there.

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You drill and tap the axle/pumpkin. Fine thread grade 8 length escapes me at the moment.

Djstorm100 said:

You drill and tap the axle/pumpkin. Fine thread grade 8 length escapes me at the moment.

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You should write up a DIY guide for this mod. I like it better than the welding because it eliminates any chance at heating and warping the axle tube.

And while I agree this method is stronger than any bad weld, a good weld should work since it only serves to bolster the strength of the OEM pin. But a good hot weld is also likely to distort the axle tube.

46Tbird said:

You should write up a DIY guide for this mod. I like it better than the welding because it eliminates any chance at heating and warping the axle tube.

And while I agree this method is stronger than any bad weld, a good weld should work since it only serves to bolster the strength of the OEM pin. But a good hot weld is also likely to distort the axle tube.

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FWIW, I never said the pins/bolts wouldn't work. I simply said a good weld will do the job just fine. I actually like the bolts idea and may do that on mine.

19COBRA93 said:

FWIW, I never said the pins/bolts wouldn't work. I simply said a good weld will do the job just fine. I actually like the bolts idea and may do that on mine.

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I agree. I've welded the tubes on all my cars (a lot) and never had an issue, but I may go the "bolt method" on the next car.

FWIW, I just got off the phone with a customer that had a 2007 GT....with a Centri blower and 4.10 gears....with a super twisted tube. He wasn't so lucky, his damage was pretty bad...