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lower a frames

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gremlin t View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlin t Quote  Post ReplyReply Direct Link To This Post Topic: lower a frames
    Posted: Mar/17/2018 at 8:34am
anyone ever weld closed the bottom of the front lower a frames to increase strength.
  I know they are not realy a frames but they  do the same job and they are u shaped 
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Lyle View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lyle Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 11:18am
I have not seen one not boxed in. What does the motor cross member or the front sway bar bolt to?
Maybe someone removed sections for restoration and never welded new pieces back in place?
I admit I have not worked on a Gremlin in years but the Pacer a couple of years ago had a fully boxed in front sub frame.
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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 11:33am
You are referring to the lower control arms?   
(A-frame is a slang due to the shape - otherwise it's upper and lower control arm)

I've not seen a reason to box them and have run auto-cross with my Javelins. 
I know some swear by boxing them in but the strut rod prevents real twisting. As far as i'm concerned the only reason to box the lower control arms is to keep them from getting crushed if they get hit. The strut is so close to the ball joint there's no real way to twist them.
But I know I'll be smacked for saying that............ it's just that I've abused more AMCs than I care to admit including auto-cross and have never lost a lower control arm. 
Unless you really abuse the heck out of it - what can be done to it if the STRUT is in place and the bushing decent at all??  Smack a hole or curb - the stress is on the STRUT, not back to the length of the lower control arm. You'd have to hit something with the arm itself. 
How can it be twisted or distorted with the strut rod bolted clean out by the ball joint?
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401MATCOUPE View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 401MATCOUPE Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 2:42pm
Sorry to contradict you Bill D but....

Yes, the boxed lower control arms were done by many Trans Am Teams, the Peking to Paris AMX from recent and I have seen a few others too.  I mechanically restored a previous SCCA 71 AMX, that was NOT heavily used and both lower control arms were twisted enough the bushings literally fell out of the arms.   LA PD did a re-inforcement that was later adopted by AMC that added a doubler plate welded to one side of the lower arms and a plate inside the upper arms, that they made the left and right arms different part numbers. 
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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 2:59pm
How could it twist with the stout strut bolted across the ball joint end - what forces would have been transmitted to the bushing end since the strut prevented it from twisting?
Even in the radical treatment I gave my early AMCs I've never twisted a lower control arm. 
Granted Trans Am was a lot faster and a lot more HP and more rigourous but something other than a force at the outside end had to do the twisting.

The plate you refer to I suspect was the weak spot where the bushing was pressed through only a single thickness of arm- that was purely a poor design, having the bushing through a single layer or thickness of steel.
I have a couple of the arms that have the extra plate welded at the bushing hole - off later cars apparently.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote electricbluesc/360 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 7:59pm
Originally posted by billd billd wrote:

You are referring to the lower control arms?   
(A-frame is a slang due to the shape - otherwise it's upper and lower control arm)

I've not seen a reason to box them and have run auto-cross with my Javelins. 
I know some swear by boxing them in but the strut rod prevents real twisting. As far as i'm concerned the only reason to box the lower control arms is to keep them from getting crushed if they get hit. The strut is so close to the ball joint there's no real way to twist them.
But I know I'll be smacked for saying that............ it's just that I've abused more AMCs than I care to admit including auto-cross and have never lost a lower control arm. 
Unless you really abuse the heck out of it - what can be done to it if the STRUT is in place and the bushing decent at all??  Smack a hole or curb - the stress is on the STRUT, not back to the length of the lower control arm. You'd have to hit something with the arm itself. 
How can it be twisted or distorted with the strut rod bolted clean out by the ball joint?


Is there anything you haven't done?    Must have been super busy...
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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 8:21pm
Yeah, but what's that got to do with anything? Many people here have participated in such things - racing, auto-cross, skiing, sky-diving, etc.
I rarely ever took any vacations and I worked my way through college, and don't sit around much. 
I can't sit much and have to always be doing - it's what people like me must do and there's no cure. (Ask Rick Green or Patrick McKenna)

Anyway - when you sleep only a few hours a night, and when your college put on an auto-cross and when you got into it for a while, well........... (that and the local cops and patrol knew me by first name HAHA)
Let's see - trained/educated mechanic, first mechanic job at 14, owned my own business at age 16, farmed several years in the 1980s, maintenance electrician license for a while, head of grounds and properties and networking for On With Life, Inc, network tech and electrician for Principal Financial Group, later head of server and desktop security for PFG, worked as a mechanic for several years, network security admin for State of Iowa, online support as a volunteer for Symantec Corp, beta and alpha tester for Symantec corporate products, adviser on online security for a local congressman, yeah, been busy - along with admin here.
Currently busy restoring cars, starters, wiper motors, alternators, suspension and brake work, plating, etc.
There's a lot I haven't done but there's still time, I ain't dead yet. LOL
Living and learning - it doesn't get better than that.


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6768rogues View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: Mar/17/2018 at 10:00pm
I would box them if I intended to do a Dukes of Hazzard barn shot. Otherwise, no.
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