UPPER CONTROL ARM EXCHANGE QUESTION

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SGBARRACUDA said:
Need to expound on your question.
Click to expand...
Need to replace my original driver side UCA due to accident. Have access to 73 Duster UCAs in really good condition at good price. My interchange manual says 68 interchanges up to 72 ... just looking for some thoughts about the difference between the 73 that makes it unusable. I'm in a full restoration and have considered disc brake upgrade but wasn't planning on that upgrade at this time.
 
Ok, now I can help. The upper ball joint change from 72 and older and 73 and newer. The stud on the 73 is larger, also the hole in the upper control arm is larger so you can't use your old ball joint in the newer A-arm. But the good news is the pre 72 A-arms are very easy to find. I have several of them.
 
73-76 UCA's won't work as they are large ball joint.
You need any UCA from 62-72 to work with your car.
They are small ball joint.
 
There are some people with wrong information. Even some of the books that people rely on are incorrect.
Here is the truth:
ALL A body cars from 1963 to 1976 with 9"front drums used the upper control arm with the small upper ball joint.
ALL A body cars built through 1972 with 10" front drums used the same UCA and Upper ball joint as the 9 inch drum cars.

In 1973, a few things did change. The cars with 9" brakes were still built with the small upper ball joints. I have seen them. I have owned them. They are not unicorns or swap jobs, they were built that way. Every one of them I have seen was a slant six model with very few options.
Also in 1973, the cars were available with 10" front drums. The spindle/knuckles they used were different than the 63-72 model cars with 10" drums. These 1973-76 10" drum cars DID use the same upper control arm and upper ball joint used in the 1973-76 11" front disc cars.
I'm not trying to insult anyone here, just trying to pass on correct information.
 
The aftermarket offers a adapter bushing that makes the smaller ball joint fit in any spindle. So large joint arms aren't absolutely part of a future upgrade/plan.
If this Duster donor has the larger ball joint, there aint no adapter to fit that larger stem in the small spindle hole.
Since the correct small ball joint replacement arm seems to be available ( per previous post ), I can't offer a good reason not to go that route.
 
That being said not to steal the thread but do you have part numbers for those control arms. I have 72 and I am pretty sure my car is a hack job and I want the correct parts installed
 
Kern Dog said:
There are some people with wrong information. Even some of the books that people rely on are incorrect.
Here is the truth:
ALL A body cars from 1963 to 1976 with 9"front drums used the upper control arm with the small upper ball joint.
ALL A body cars built through 1972 with 10" front drums used the same UCA and Upper ball joint as the 9 inch drum cars.

In 1973, a few things did change. The cars with 9" brakes were still built with the small upper ball joints. I have seen them. I have owned them. They are not unicorns or swap jobs, they were built that way. Every one of them I have seen was a slant six model with very few options.
Also in 1973, the cars were available with 10" front drums. The spindle/knuckles they used were different than the 63-72 model cars with 10" drums. These 1973-76 10" drum cars DID use the same upper control arm and upper ball joint used in the 1973-76 11" front disc cars.
I'm not trying to insult anyone here, just trying to pass on correct information.
Click to expand...

Yes, there are people with the wrong information, yourself included. I've been wrong in the past about the 9" drums, I used to think they went away in '73 but by all the factory literature it was '74.

9" drums were not available starting in 1974 according to any of the factory literature. You believe the factory literature for everything else, so, I don't see how it's not valid here. According to the factory, '74+ were all 10" drums, and those had large ball joint spindles and UCA's. If the books are wrong, show us the evidence.

Starting in 1973 all V8's got disk brakes. So, only /6 cars could have had drums up front. Disks were optional for the /6 and if you got a towing package you got disks. '73 was a transition year, 9" drums were still listed as being standard in front. But only for /6 cars without a sure grip rear, the sure grip upgraded you to 10" drums. I honestly don't know if the 1973 9" drums were small or large ball joint, although I would suspect they were small ball joint as the factory used up the remaining stock. And I haven't seen or heard of a 9" drum, large ball joint spindle (although that's obviously not proof). But that's 1973 only. The front drum cars stayed small bolt pattern the whole time, and drums went away completely for the front in January of 1975.

So-
All 1973-76 A-body disk brake cars were BBP and had large ball joint UCA's, the disks were standard for V8 and optional with a /6
All 1973-76 A-body 10" front drum cars had the 5x4" SBP and used large ball joint UCA's. And '74+ were all 10" front drums if they had drums.

1973 was the last year for 9" front drums.

As for cars 1974 or later with 9" drums, when you have one you can prove had them from the factory I'd be happy to change my statements. But just having a '74+ car with 9" front drums doesn't mean it came that way from the factory. I've swapped drums onto parts cars that came with disks just to keep them rollers, and used the disks to upgrade my other cars. I know I'm not the only one too. Of course it's possible there may have been some leftover cars at the very beginning of '74 with leftover 9" front drums and SBJ UCA's, it's Ma Mopar and there weren't many absolute cut off dates. Using leftovers was pretty common, but that typically only lasted a few months at the beginning of each model year. So, after early '74 I'd have to see real evidence. And who knows, they could have used up all the 9" drum spindles before they even got to the end of the '73 model year, since the factory was transitioning out of the small ball joint UCA's. Just as plausible. And that makes more sense, after all, starting in '73 the factory was transitioning the A-body line to use the same parts as the B/E body lines. Same upper ball joints, same lower ball joints, same rotors and bearings, same side markers (that started in '72), etc. Cost savings for the gas crunch. 9" drums require a bunch of parts unique to only 9" drums. Remember, not only did they use the small upper ball joint and UCA's (shared with the SBP disks up to '72), they used a lower ball joint they didn't share with anything else, even the SBP disk cars didn't use the 9" drum lower ball joints. And of course all of the brake parts were unique to the 9" drums and since they were SBP they were A-body only.

I've posted this info before, but here it is again. All this is from The 1970 Hamtramck Registry Home Page, the red highlights are mine. You don't have to believe me, but, "a car I saw in a junk yard" is not proof the factory literature is wrong. I've seen V8 cars with /6 K's, disk cars that had drums, 7.25's in cars that should have had 8 3/4's, BBP and SBP on the same car, you name it. That doesn't prove the factory did that, not after 40+ years. Especially with the '73+ cars because they get used as donors all the time, and people swap earlier parts on to keep them rolling and send the leftovers to the junk yard.

1973
73_Dart0025.jpg

1974
74_Dart (21).jpg

74_Valiant_Duster_0022.jpg
 
What kind of crap is this....?
"9" drums were not available starting in 1974 according to any of the factory literature. You believe the factory literature for everything else, so, I don't see how it's not valid here. According to the factory, '74+ were all 10" drums, and those had large ball joint spindles and UCA's. If the books are wrong, show us the evidence.

I believe the factory literature> Where did you arrive at this conclusion?
According to the factory, '74+ were all 10" drums? Uhh...NO, many were disc brake cars.
Evidence?
I'm not claiming to believe everything that I read. Books have errors. Back when these cars could be found in great numbers in the wrecking yards, I recall seeing later model Beak Darts and 73-76 Valiant/Dusters with 9 inch drums up front. Not all of them, just some. I also owned a 1976 Dart 2 door with a slant 6, an automatic and 4 wheel 9 inch drum brakes. That car was so basic, I think the carpet and automatic transmission were the only options.
Now, before I owned that 76 Dart, it is possible that the car may have been a disc brake car. To get the car to the way that I owned it, someone would have had to swap over the upper control arms, front brake assemblies, master cylinder and proportioning valve/distribution block, rear axle and maybe even a drive shaft. Yes... all of that to put an ugly green slant six Dart back on the road.
 
Disc brakes became mandatory in Jan 1976 not 1975. My 76 came with the 10" drums only cause it was made in the late months of 75
 
timekammer said:
Need to replace my original driver side UCA due to accident. Have access to 73 Duster UCAs in really good condition at good price. My interchange manual says 68 interchanges up to 72 ... just looking for some thoughts about the difference between the 73 that makes it unusable. I'm in a full restoration and have considered disc brake upgrade but wasn't planning on that upgrade at this time.
Click to expand...
If you still have access to those UCA's and they are large ball Joint I am interested in them. I am putting discs on my 1971 duster and 1969 Dart GT Vert
 
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