Club Cobra - Adjusting Ford 9" Rear Axle in B & B Cobra

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Adjusting Ford 9" Rear Axle in B & B Cobra

I'm in the finishing stages of the rebuild on my B & B Cobra and have some questions about the rear end alignment. I took the car in to have the front alignment done( just replaced the front end with tubular arms and coil overs) and was told by the alignment guy that the rear end was out of specs. I took the car home did some measurements and found the axle sits 1/2" to the left of center and the front to back measurements has the right side a 1/4" longer then the left. My question is this...should I just run it? Is it "out of specs" to the point I'll notice handling-wise or tire wear-wise? Should I take the time and money to get adjustable upper control arms and try to correct the axle position? I already have adjustable lower arms but I believe they are only good for setting pinion angle? Can the upper arms be adjusted to correct off-center AND front to back measurements independently? Considering the geometry of the 4 link system, it seems to correct for one would effect the other, not necessarily in the direction desired. I don't mind doing the work and the cost is minimal, as long as it's something worth doing and I don't end up chasing my tail. Thanks for throwing in what you got..always appreciate the help.

Kim

Kim, I don't think the adjustable uppers will help a lot in correcting the position if the axle is not centered.

I'd get a new axle housing. There are several companies that offer 9" housings custom-made to your specs. They're not that expensive: 9" Ford Fox Body Mustang Axle Housing 9 inch Rearend | eBay

Simon

you can correct the front to rear 1/4" problem by cutting a 1/4" out of the lower control arm.
to move the rear end 1/2" is harder. Look at the way to upper and lowers are installed. Sometimes washers are used as spacers.
The front to the rear measurement is important but I think the side to side no so for a street car.

Call Barry McGill
sorry I don't have his number but I'm sure someone will have it.

Dwight

The axle housing doesnt appear ro be bent. I have adjustable lower arms but found they only tilt the diff housing...the upper arms keep the diff in a solid position left to right and front to back. No spacers/washers to play with in the uppers to reposition side to side.

Double post. See below.

Kim, I can help you with that. It is totally adjustable if you have heim joints and contingent on the arms being the right length. Which there has been a problem in the past. By coincidence I am readjusting mine right now. The lower arms set the wheel base and squareness with the frame. The upper arms set the pinion angle and center the axle between the wheel wells or frame. I hope your axle is straight. I had to have Currie straighten mine.

It can be an involved process but you can do it. It would take to long to write it here. Send me a PM with your ph number and we can talk on the phone. I am retired and am available most of the time.

Added: Sent you a PM with my number.

Akinbeau:

Left as it is this will affect handling. Enlist the help of someone familiar with chassis design. You must verify the pivot mount dimensions through an "X" measurement from the front lower control arm mounting points, they must be exactly the same. Once this is confirmed you can THEN modify as necessary the locating mounts on the axle housing. The upper and lower rods that control the pinion angle can use threaded ends with rubber bushings (street rod fare) or high quality Rod ends (Hiem Joints). Use a RH & a LH on each rod so the tube can be rotated and effect the overall length of each rod as needed. This IS crucial to the oveall handling of the car. The Panard Bar must allow for dimensional change also.

Here is an example:

http://www.clubcobra.com/photopost/d...re_158__2_.jpg