Finally got a real A-Body!

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the_fatman

the_fatman

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Been on for a while admiring all the actual classics pretending my pt cruiser could be accepted..... now I am officially an A-body owner. I traded the pt for a 75 duster /6 with amazing clean body panels and v8 904 trans. I have a 340ci out of a demon that's bored .030 over. Not sure what else was done my dad passed away b4 I took a huge interest in it. But I am finishing what he started when I was a kid. I can't upload pics from my phone but I am going to try to get on a computer to get em up,

Now I got the bug to get the thing dropped in. I would like to change the front drums to disc. Am I lookin at a major parts swap? Can I reuse the spindle in the car now or do I need a disc brake spindle.
 
Yes you need to change the spindles. Do you have big bolt pattern now? If so even better.
 
moparker said:
Yes you need to change the spindles. Do you have big bolt pattern now? If so even better.
Click to expand...

I have the small bolt pattern so can I use the hub out of my current spindles in the disc spindles? also are all 8 3/4 rears big bolt pattern? If so I will just leave the big pattern in the discs.....
 
Congrats on picking up your A-body! Post all of your questions here. Lots of great people will get you the straight info.
 
I believe some /6 cars after 72 still got SBP, with drums. If the car was ordered with discs, then it came BBP since they were no longer using 4 piston callipers, but single.
As for 8 3/4 rears, it's big bolt if its from a B/C/E body, but if its from an A body, it will be small bolt.
 
oh ok all of the cars I got always had disc so they were big bolt


70DartMike said:
I believe some /6 cars after 72 still got SBP, with drums. If the car was ordered with discs, then it came BBP since they were no longer using 4 piston callipers, but single.
As for 8 3/4 rears, it's big bolt if its from a B/C/E body, but if its from an A body, it will be small bolt.
Click to expand...
 
Nobody really answered your disk & hub question. Most people use the later (73+) front disks. In those, the hub is integral with the rotor. It is big-bolt pattern, which is a 4.5" circle, but measures ~4" across 2 opposite bolts center-center.

Re whether the disk and drum spindles differ - I thought all cars had front disk brakes after 1972 as a federal mandate. Is your 1975 a U.S. car? If not, you need info from the country it was made (Brazil, Aus).

For 1972 (?) and earlier, front disk brakes were a Kelsey-Hayes 4-piston caliper with a 2-part rotor and hub. It is SBP (4"D bolt circle). The hub, spindle, and lower ball joint differ between disk and drum cars. The parts are rare and expensive today. Mustangs used almost the same caliper.

Another consideration is the upper ball joint and control arm, which changed in 1973.

Finally, look at after-market designs. Scarebird's is affordable and uses the existing drum hub and spindle, but not for all models. You can find him on ebay and he posts on FABO. Stainless-Steel Brakes and Wilwood have conversion kits, but ~$700, so you have to really want disks.

Also, if your front was SBP, the rear would originally be SPB. Mopar could never have sold a car that needed two spare tires.
 
IIRC, A=body 8.75's were small pattern up to 72. then went to big pattern.
 
Every /6 drum brake car I have ever seen had the small bolt pattern and the disc brake cars had big bolt pattern from '73 on. My '73 Sport was a /6 with drums and sbp
 
all A-body 8 3/4" rears were small bolt pattern from the factory
all A-body 8 1/4" rears were big bolt
the 7 1/4" rear came in both small and big bolt

all drum brake A-bodies were small bolt no matter the year
(disk brakes were not mandatory until 76 I think)

the early 4 piston kelsey hayes disk brakes were all small bolt 5X4"
the later single piston disk brakes were all big bolt 5X4 1/2"

a link to scarebird and SSBC

http://www.scarebird.com/index.php

http://www.ssbrakes.com/
 
Thanks for all the warm welcomes.... I am from nw ohio about 30-45 mins from the ohio indiana border. Thanks for all the brake and rear end help. If anyone is interested I have a virgin cut down(really short) ford nine inch I would be willing to trade for a 8.75 just pm me its at my uncles back home but if anyone is really interested I can take a trip on my day off to measure how short it is.
 
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