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Bending 3rd member for camber

Old 09-23-11, 01:26 PM
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Bending 3rd member for camber

Hi guys,

I've heard of people bending the rear axle housing in order to create negative camber. I've heard a few wisps of detail on how it is done, but not nearly enough information to complete the job.

Anybody have any details on this? Done it yourself? Any help would be greatly appreciated.



.
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Old 09-23-11, 01:37 PM
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I've heard it done before on other cars, but I always thought you wouldn't gain enough to be worth the effort and other problems you will gain. The extra stress on the bearings would burn them up faster and you will weaken the housing, whether you use heat to bend it or a ram like a frame shop uses for bent frames. I would be interested, though, if there are enough success stories out there. Our silly solid axle rear ends can use all the camber we can get.
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Old 09-23-11, 01:55 PM
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From what I have heard/read over the years, there is a certain target that can be reached without causing significant added stress to the bearings. I believe this number was something like 1.5 - 2 degrees of camber.

Most of the top performing (National Class) autocrossers seem to have had this done. I read it in a lot of adds, etc. where they list their mods.

I'm just toying with the idea of installing my Trilink/Panhard setup over the winter, and if I do that, I might as well take the extra step and bend the member too.

Thanks for the input. Hopefully we can draw out some solid info on this topic.
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Old 09-23-11, 02:44 PM
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back in the pro7 days, my friend would chain the diff to an I beam (like the kind you build office buildings out of) and then jack up each end.

i think you're shooting of more like -1. much more than that and you'll be wearing stuff out
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Old 09-23-11, 03:03 PM
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*****Note- I have not personally done this, but have talked to someone that has*****

Support the axle on the outside. Cut a slice/notch in the top of the axle tube near the diff. Heat the tube with an Oxy/Acetylene torch. When the desired camber angle is achieved, cool the housing and weld. Repeat on the other side. This will put some initial bind in the axle splines. Supposedly they will "break in". The advantage is it does not stress the bearings.
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Old 09-23-11, 03:05 PM
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Originally Posted by j9fd3s View Post
back in the pro7 days, my friend would chain the diff to an I beam (like the kind you build office buildings out of) and then jack up each end.

i think you're shooting of more like -1. much more than that and you'll be wearing stuff out
-1 sounds about right for target camber. Also that was the max camber allowed on a Pro7 car
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Old 09-23-11, 03:35 PM
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Yeah, it could be 1 to 1.5 that I've seen/read about.

I discussed this with Billy a couple of years back, but just real quick as part of another conversation. If I understood him correctly, he said that you run a bead along the top of the housing, then as it cools it contracts and produces the bend.

Does that sound right to anyone?
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Old 09-23-11, 04:43 PM
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Don't forget you run the risk of effecting toe.
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Old 09-23-11, 10:49 PM
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.9 degree is the number we came up with that didn't kill everything that rotated. Just heated up the top of the axle tube closer to the pig and quenched it to shrink the metal a little. Check your housing before you start, it may already have some camber and it won't be equal.
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Old 09-26-11, 07:30 AM
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Yeah, and I still need to make sure that the housing I plan to install hasn't already been modified. Just laying the groundwork for a possible trilink install this winter.
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Old 09-26-11, 09:33 AM
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The axles splines can be crowned for additional camber so that you don't eat up axles, carriers, and bearings. Starts to depend on how much money you want to throw at it.

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Old 09-27-11, 01:20 PM
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Hmm, that looks yummy! Probably a bit further than I am willing to go at this time though.
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Old 09-27-11, 05:53 PM
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Originally Posted by Kentetsu
Yeah, it could be 1 to 1.5 that I've seen/read about.

I discussed this with Billy a couple of years back, but just real quick as part of another conversation. If I understood him correctly, he said that you run a bead along the top of the housing, then as it cools it contracts and produces the bend.

Does that sound right to anyone?
Didn't do it that way, in the past just partially sliced the axle tube with a grinder - axles out! - each side equally. Then welded up the cut, which was enough to draw it into position.

The barrel splines on the axle above ^^^ look like they're out of a full floater...proper and best way to go.
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Old 10-21-11, 05:39 PM
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Most road race and circle track guys use the torch. You heat the side you want the axle tube to go. If you want to get negative camber, heat the top. It shrinks when cooling. Do not ever cut the tube.

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Old 10-22-11, 10:53 AM
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Every 1st-gen I've had on the alignment rack had a half-degree of negative camber already. The axle housings are flimsy and after may thousands of street miles, they take a set.

It's amazing how much "give" axles have. The amount of toe-in my rearend has is visible and shocking. (And completely unintentional)
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