digitalman2112
07-01-2012, 07:02 AM
I'm in the process of ordering the front suspension and front / rear brakes for my '68 Firebird (see signature for more info on the car). A few years ago the car went to Frank @ Prodigy, who told me I had an odd rear axle setup, and he wasn't sure what kit would work with it. I don't know that he spent time doing the detective work (I wasn't ready to order the brakes)...but it has bugged me and it is time to figure it out (or have the rear end modified if needed).
Here is what I know - not all of this may be relevant, but including just in case:
The previous owner's documentation lists:
"12 Bolt rear end with 308 gears"
"Powertrax limited slip rear end"
"Impala shortened rear axle"
"Large Impala rear drum brakes"
Yesterday, I pulled off a rear drum (11" drums), and started measuring. I used the Wilwood axle flange page (http://www.wilwood.com/BrakeKits/BrakeKitApp.aspx) as a guide.
My flange is the square design shown below (from the Wilwood diagram), I verified the bolt spacing measurements match that diagram - the bolt spacings are the 3.396 x 2.656.
61427
The left two of those axle flanges show an axle tube OD of 3.420, which I clearly do not have - I measured my axle tubes at 3", they could be the 2.940 mentioned (I wasn't measuring with .06 accuracy...) which leaves the Chevy C10 on the right. I can see the the axle tubes were cut and rewelded, so it is very possible I have mix & match parts from different cars / years.
I'll need to pull off the drum brakes to measure the axle offset, but I'm guessing it is approx 3" - I didn't have time to tear into a brake setup yesterday, but will do it soon so that I can get a good pic of everything.
I only spotted one code on the differential - J276 (if I read it correctly) - Which means the center was cast on October 27th of 1968 (if I understand how those codes work...)
61429
I need to look for stamped numbers on the housing and axle tubes - they were not visible yesterday, some cleaning may be required.
I'm hoping someone that knows more than I do can help me identify what I have, or can point me in the right direction. In the end, I just want to get rear brakes, and my brand / style selection may be limited by the rear axle configuration, so I'm trying to get it figured out... please feel free to suggest other things I can look for / measure / identify that get me there...thanks!
Here is what I know - not all of this may be relevant, but including just in case:
The previous owner's documentation lists:
"12 Bolt rear end with 308 gears"
"Powertrax limited slip rear end"
"Impala shortened rear axle"
"Large Impala rear drum brakes"
Yesterday, I pulled off a rear drum (11" drums), and started measuring. I used the Wilwood axle flange page (http://www.wilwood.com/BrakeKits/BrakeKitApp.aspx) as a guide.
My flange is the square design shown below (from the Wilwood diagram), I verified the bolt spacing measurements match that diagram - the bolt spacings are the 3.396 x 2.656.
61427
The left two of those axle flanges show an axle tube OD of 3.420, which I clearly do not have - I measured my axle tubes at 3", they could be the 2.940 mentioned (I wasn't measuring with .06 accuracy...) which leaves the Chevy C10 on the right. I can see the the axle tubes were cut and rewelded, so it is very possible I have mix & match parts from different cars / years.
I'll need to pull off the drum brakes to measure the axle offset, but I'm guessing it is approx 3" - I didn't have time to tear into a brake setup yesterday, but will do it soon so that I can get a good pic of everything.
I only spotted one code on the differential - J276 (if I read it correctly) - Which means the center was cast on October 27th of 1968 (if I understand how those codes work...)
61429
I need to look for stamped numbers on the housing and axle tubes - they were not visible yesterday, some cleaning may be required.
I'm hoping someone that knows more than I do can help me identify what I have, or can point me in the right direction. In the end, I just want to get rear brakes, and my brand / style selection may be limited by the rear axle configuration, so I'm trying to get it figured out... please feel free to suggest other things I can look for / measure / identify that get me there...thanks!