#1  
Old 02-04-2019, 01:37 PM
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73LeMans 73LeMans is offline
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Default Dimensions of front lower control arm

Any one know or have access to the stock dimensions of the drivers side lower control arm for the 73 A body? Mine is tweaked and would like to know how far off it really is. The 73 service and assembly manuals make no mention of the dimensions. None of the aftermarket arm makers quote any measurements either. (Detroit speed, QA1, Fatman Fab etc).

- inside, busing to bushing measurement
- outside busing to bushing
- and/or ball joint center to bushing center
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  #2  
Old 02-04-2019, 02:27 PM
cdrookie cdrookie is offline
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Give me a little bit and I will get you the info.
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Old 02-04-2019, 02:53 PM
cdrookie cdrookie is offline
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Im sure my 75 arms are the same.

I got 11 7/16 for inside to inside

15 3/8 outside to outside

And approx 16 from ball joint to bushing centerline measuring on the upside of the arm.

I took the in/out measurements from the arm itself not from the bushings.
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Old 02-04-2019, 11:27 PM
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73LeMans 73LeMans is offline
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Quote:
Originally Posted by cdrookie View Post
Im sure my 75 arms are the same.

I got 11 7/16 for inside to inside

15 3/8 outside to outside

And approx 16 from ball joint to bushing centerline measuring on the upside of the arm.

I took the in/out measurements from the arm itself not from the bushings.
I would have thought the 75s to be the same too, but Moog sells a different bushing for a 75 vs 73/74, so must be a slightly different piece. Not sure what that difference is though since our measurements are pretty close. Bushing diameter perhaps.

My measurements are as follows:

11 7/16 inside arm to arm (10 7/16 inside bushing to inside bushing)
14 7/8 outside arm to arm (15 1/4 outside bushing to outside bushing)
The same approximate 16 inches from ball joint center to bushing center on the upside. (downside too!) Close to being the same without the bushings involved, but thats the key to what I'm trying to figure out.

Here's the problem. (And I pretty much know the solution I need to employ, I just dont believe it since so little has changed since the arm was last working on the car)

My arm doesnt go back where it belongs. Seems like its too wide to fit in the boxes in the frame. Thinking I must have screwed something on the arm pressing out the old bushings, I shrunk the distance from inside bushing to inside bushing by about 1/4" using a press to bring the bushing ears closer. Still too wide. I can compress it more but then my bolt centers on the arm and the frame wont line up, so something is off. And not by a little!!

The backstory is long and sorted, (always is with this car) but early in its life, (1979?) the engine crossmember used to contact some local railroad tracks from a combination of low ride height, and terrible streets. Suffice to say, the engine cross member took quite few bad whacks on that drivers side. There no doubt pushed that front LCA bolt to a new spot. I've always dealt with it though - yeah its tough to align, and initially there was premature tire wear etc, but it always worked and the suspension was never too difficult to get in and out of the car. And when I finally fixed an elongated LCA suspension hole on the passenger side frame box, the alignment came back to semi acceptable. Least the tires stayed on it. That was 20 years ago.

The problem today is I'm using the Delrin bushings and they have zero tolerance for things being out of whack. There is nothing exact on this front end and as mentioned, the arm appears to be too wide to go back in place. I was thinking the bushings themselves are too wide which is why I'm seeking measurements. I expected a little tweaking to be done, (passenger side went in without problem) but this is too large a gap to cover, and I refuse to believe I've always made up this drastic difference with the poly bushings.
__________________
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Who needs nice and pretty, when you can have mean and nasty?
KRE Aluminum headed 463CID 73 LeMans. Used to run 10.6x @ 124.55. 3700lbs
.
2019 brings all new systems, and almost all new engine.
Swinging for 9s.
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