Tubular UCA install questions

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rich_mc

rich_mc

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Disclaimer - I'm not a mechanic but am learning....

Been doing a rebuild/upgrade on the suspension on my 76 Scamp. Did the LCA rebuild with the forged pivot pins from PST. Finally managed to get the torsion bars back in earlier today. Now moved on to the tubular UCA's and am confused.

The set I got is here: 1963-74 Dodge Plymouth Chrysler Mopar A-Body Tubular Upper Control Arm Set The description indicates they are for 63-76, but the part number of TCA-U6374AB makes me question if they are actually only good for 63-74... hmmm... maybe... Also that the title of the webpage link says 63-74, but when you go to the page it says 63-76... so maybe there's something different on the after 74 models and the webpage never got updated?

Anyway, after a bunch of wire brushing, scraping, and using a 12" crescent wrench to try to bend out the mount tabs a bit, I was finally able to get the bolt into the front. Still struggling with the back bolt alignment. My issue is that the UCA hits an edge of the mount tab and stops its downward travel very high.

Here is the drivers side with the UCA pivoted up. Front bolt is in - back bolt still out.

20221105_212951-X3.jpg


Here is the UCA pivoted down as far as it will go:
20221105_213004-X3.jpg


Here is where it is hitting stopping downward travel:

20221105_213018-X3.jpg


Here's the LCA with the spindle and lower ball joint temporarily bolted in place to try to figure out what my issue is (NOTE - SECONDARY QUESTION - Is the adjustment blade in an ok spot or do I need to try to rotate it up another hex flat 60 degrees higher - I'm not sure I can get it that much higher without hitting the frame rail, so may not even be possible):

20221105_213026-X3.jpg


Here is the UCA pivoted as low as it will go and the LCA pushed as high as I can get it by hand with the torsion bar adjuster bolt backed out all the way so it's loose.

20221105_213149-X3.jpg


Obviously the upper ball joint is still several inches too high to be able to connect to the top of the spindle, even with the top pivoted down as far as it will go and the bottom pivoted up as far as it will. The LCA's were rebuilt and are the same ones I took off the car, so it seems they should be usable.

Am I overlooking something obvious with the tubular UCA install? I even thought maybe I was trying to put the wrong one on the wrong side, but holding the other one up looks even more manked up than this one does....

I could likely cut out that tab that is crashing into the UCA and stopping its downward travel, but haven't been able to find a mention of anyone else having to do that...

Ideas??
 
It's a common issue and that piece must be trimmed to allow the upper arm its full range of travel.
 
The tubular UCA’s will fit all A-bodies up to ‘76, there was no change in ‘74 that effect the fit of the UCA in the mounts.

The mounting tabs weren’t designed for the shape of the tubular UCA’s and the forward mount often requires some trimming. Like this…

92860871-5CB8-4C1B-9D08-97019FDF1274.jpeg
 
Yeah, there you go. I knew somebody had an example. The trick is, you want to leave as much of that 90* angle as possible. That's where the strength is.
 
RustyRatRod said:
Yeah, there you go. I knew somebody had an example. The trick is, you want to leave as much of that 90* angle as possible. That's where the strength is.
Click to expand...

Exactly so!

The upper outermost corner that’s just free in space does pretty much nothing. The 90° bend and the section that’s welded to the frame at the bottom is where the strength comes from. So you want to cut an arc that leaves as much material down close to the frame as possible. Clearly you don’t want anything going metal to metal, but you don’t want to take out more than what’s necessary.

Also, looking at the OP’s pictures more closely it kinda looks like that tab has already been welded on/modified from factory. Hard to tell from a couple pictures on the internet but it looks like it’s got grinder marks on it, and it’s overall shape doesn’t match the mounts I’ve seen. That by itself doesn’t mean too much, I haven’t seen nearly enough mounts to say some of them didn’t look like that. But for what it’s worth I think it looks like it’s been repaired or modified at some point previously
 
My upper tubular CA sure don't look like those, and I didn't have to grind anything.
Granted, this picture is of my Gerst suspension, on my '69, but my '72's stock front suspension has a tubular upper arm and looks the same.

20200318_211437.jpg
 
CRUZE 418 said:
My upper tubular CA sure don't look like those, and I didn't have to grind anything.
Granted, this picture is of my Gerst suspension, on my '69, but my '72's stock front suspension has a tubular upper arm and looks the same.

View attachment 1716007610
Click to expand...

There’s a couple reasons for this. First, not all the UCA mounts look the same. Somewhere on here I posted a few different mounts, the tab that interferes is shaped different on all of them. The other reason is your UCA’s have the wide “U” shape, which locates the arm of the UCA differently.

Typically UCA’s with the tighter “V” shape cause more interference at the mount because of the angle the arms take leaving the mount. However, that angle also means they allow more tire clearance. The wider “U” shaped arms limit rim width and backspace some if you’re trying to max out wheel width up front.
 
Ok- did the trimming and have the first one so it will move throughout full travel from top until it hits the rubber stop at the bottom.

How easily should it pivot? Like should gravity lower it to the bottom, or is it ok if I have to push it up/down with moderate force?
 
rich_mc said:
Ok- did the trimming and have the first one so it will move throughout full travel from top until it hits the rubber stop at the bottom.

How easily should it pivot? Like should gravity lower it to the bottom, or is it ok if I have to push it up/down with moderate force?
Click to expand...
if the cam bolts are tight, you will need to overcome that friction to move it. See how it moves without the strut bar attached, then attach the bar and retest for free movement.
 
Did you tighten the LCA pivot pin with the LCA flopped down? If so loosen the pivot pin nut and don't tighten it until you have the whole thing put together and have the weight of the car on the wheels with the front end height adjusted. That way the rubber bushing isn't loaded up, causing premature failure.
 
rich_mc said:
Ok- did the trimming and have the first one so it will move throughout full travel from top until it hits the rubber stop at the bottom.

How easily should it pivot? Like should gravity lower it to the bottom, or is it ok if I have to push it up/down with moderate force?
Click to expand...

What UCA bushings are in those tubular uppers?

It looks like they’re poly bushings. If that’s the case, they should be well lubricated and there should not be a lot of resistance to moving the UCA up and down.

If they’re rubber bushings, then you have to flex the rubber to get the UCA to move. But those aftermarket UCA’s don’t appear to have stock bushings.
 
Isn't there a ball joint difference between 72 and 73? how can there be just one UCA that fits 63 to 76?
 
str12-340 said:
Isn't there a ball joint difference between 72 and 73? how can there be just one UCA that fits 63 to 76?
Click to expand...

The website ad says they’re for 73+ spindles. So large ball joints, but the UCA’s themselves should fit all A-bodies 63-76 as long as a 73+ spindle is used.

I also see on the listing they have a Delrin bushings at the UCA. So, there really shouldn’t be much effort required to move them up and down.
 
72bluNblu said:
What UCA bushings are in those tubular uppers?

It looks like they’re poly bushings. If that’s the case, they should be well lubricated and there should not be a lot of resistance to moving the UCA up and down.

If they’re rubber bushings, then you have to flex the rubber to get the UCA to move. But those aftermarket UCA’s don’t appear to have stock bushings.
Click to expand...
They are indeed poly bushings. Right now they fit tight enough that pivoting them up/down is almost a 2 handed job, but not difficult... definitely staying still unless moved by hand. I did end up having to pop the metal caps out of the bushings on the inner side of each arm and use the grinder to thin them out a bit, otherwise they simply would not slide into position on the car. Either bushing stack would fit into their respective position, but not both at the same time. Like the 2 legs were just a hair too close together.

I'm hoping to get #2 installed tonight and will see how it goes in comparison to #1.
 
str12-340 said:
Did you tighten the LCA pivot pin with the LCA flopped down? If so loosen the pivot pin nut and don't tighten it until you have the whole thing put together and have the weight of the car on the wheels with the front end height adjusted. That way the rubber bushing isn't loaded up, causing premature failure.
Click to expand...
Thanks for the note- I did tighten it up but have the poly bushings on the LCA pin- from what I read on here that is only a concern with the rubber bushings.
 
rich_mc said:
They are indeed poly bushings. Right now they fit tight enough that pivoting them up/down is almost a 2 handed job, but not difficult... definitely staying still unless moved by hand. I did end up having to pop the metal caps out of the bushings on the inner side of each arm and use the grinder to thin them out a bit, otherwise they simply would not slide into position on the car. Either bushing stack would fit into their respective position, but not both at the same time. Like the 2 legs were just a hair too close together.

I'm hoping to get #2 installed tonight and will see how it goes in comparison to #1.
Click to expand...

Ugh, I don’t like that!

It’s not uncommon for the UCA mounting ears to get a little compressed/bent if the bolts are over tightened. But with Delrin bushings UCA’s should articulate easily. If the UCA’s don’t fit into the mounts correctly that is definitely an issue.
 
72bluNblu said:
Ugh, I don’t like that!
Click to expand...

Ugh- I didn't like it either! I would've been much happier if they'd have slid right into place like they should have, but I'm quickly learning nothing goes as smooth as you hope on these projects.
 
#2 is in... takes about the same effort to lift/lower as #1, so I'm gonna guess it's ok... now ready to move on to these giant brakes :):thumbsup:
 
rich_mc said:
#2 is in... takes about the same effort to lift/lower as #1, so I'm gonna guess it's ok... now ready to move on to these giant brakes :):thumbsup:
Click to expand...
You did grease them, right? Urethane takes some special grease too.....I forget what it's called.
 
RustyRatRod said:
You did grease them, right? Urethane takes some special grease too.....I forget what it's called.
Click to expand...
My poly bushings came with a white silicone based grease that really adheres to the bushing and is impervious to water & oils. Like the old commercial "a little dab will do 'ya" when assembling. I used a moly based grease in my grease gun.
 
How did the upper bump stops look
After instal of tubuler arms
Do the line up
 
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