Lower A-arm geometry
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Lower A-arm geometry
Since my paint work has come to a halt momentarily, I was going over my chassis again.
From what I can see the right rear bolt of the right lower A-arm is sitting about 10 mm lower than the other. Is this condition common and if so, what can be done ?
There is no frame damage, nor damage to the bracket of the lower A-arm on the frame.
From what I can see the right rear bolt of the right lower A-arm is sitting about 10 mm lower than the other. Is this condition common and if so, what can be done ?
There is no frame damage, nor damage to the bracket of the lower A-arm on the frame.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Since my paint work has come to a halt momentarily, I was going over my chassis again.
From what I can see the right rear bolt of the right lower A-arm is sitting about 10 mm lower than the other. Is this condition common and if so, what can be done ?
There is no frame damage, nor damage to the bracket of the lower A-arm on the frame.
From what I can see the right rear bolt of the right lower A-arm is sitting about 10 mm lower than the other. Is this condition common and if so, what can be done ?
There is no frame damage, nor damage to the bracket of the lower A-arm on the frame.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
But if the cross shaft bolts aren't centered in the a-arm, that would imply your bushings have collapsed.
Or those bushings can also completely disintegrate like mine did. See below...
Last edited by wcsinx; Jun 3, 2010 at 01:05 PM.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
It's difficult to put it on to a picture. When measuring teh distance from the rear bolt of the top A-arm, it's 10 mm shorter on the right side.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Now I'll say this because I have a bit more insight with this last post of yours. You say you have new poly bushings installed. One thing I noticed when I redid my bushings is that you have to keep the cross shaft centered in the a-arm. The end bolts will try to pull it one direction or the other, and they don't bottom out in the cross shaft so they need to be torqued simultaneously. Otherwise, if you torque bolt 1 all the way then flip the a-arm around and torque bolt 2, you'll find the cross shaft is now off center in the a-arm yanked over towards bolt 1, and bolt 2 won't have near as much thread engagement.
Is this perhaps what you're seeing?
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Team Owner
Joined: Mar 2002
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And FYI, it's not a misalignment of the bushings. They don't move. It's a mis-centering of the cross-shaft.
Melting Slicks
Joined: Jun 2009
Posts: 2,343
Likes: 4
From: Anderson SC
I'm doing my left A-arms right now and I can assure you that both ends were and are to be tightened so that the bolt on each end is indeed bottomed on the cross shft, or rather the inner sleeve. If you have a "centering issue" then your A-arms got "spread" when the old bushings got banged out. There should be no way to "off center" the cross shaft at all. Really.
The inner sleeve has teeth at each end and those teeth need to engage the crossshaft and the big washer. At that point the center bushing sleeve is captured and will not turn on the shaft at all. It turns with the shaft.
That's why you need to wait to tighten those bolts if you are using rubber bushings. Poly bushings can rotate on the sleeve and in the shell so you can tighten those. The rubber bushings only "flex", they don't rotate - so you need to have the car's weight on the them before tightening them - because tightening them fixes the position of the two inner sleeves for good.
I'm very sure of this procedure, and the "why's" of it.
-W
PS: Nothing in this post speaks to the OP's problem. It was just to correct the shaft centering info.
Last edited by Clams Canino; Jun 3, 2010 at 06:17 PM.
Team Owner
Joined: Mar 2002
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The bolts don't bottom out in the a-arm. I can assure you of that. But now you've got me thinking, Clams. You are right in that the inner sleeve should seat on both the lip on the cross shaft and the retaining washer. So on second thought, I think I must have been seeing the bushing compress on one side and then the other. I must ponder on this.
On the lower arms, torqueing one side then the other got me uncomfortably little thread engagement on the second bolt. I guess I could've kept going, and I either would seated the sleeve or stripped the hole!
On the lower arms, torqueing one side then the other got me uncomfortably little thread engagement on the second bolt. I guess I could've kept going, and I either would seated the sleeve or stripped the hole!
Last edited by wcsinx; Jun 3, 2010 at 05:58 PM.
Melting Slicks
Joined: Jun 2009
Posts: 2,343
Likes: 4
From: Anderson SC
The bolts don't bottom out in the a-arm. I can assure you of that. But now you've got me thinking, Clams. You are right in that the inner sleeve should seat on both the lip on the cross shaft and the retaining washer. So on second thought, I think I must have been seeing the bushing compress on one side and then the other. I must ponder on this.
On the lower arms, torqueing one side then the other got me uncomfortably little thread engagement on the second bolt. I guess I could've kept going, and I either would seated the sleeve or stripped the hole!
On the lower arms, torqueing one side then the other got me uncomfortably little thread engagement on the second bolt. I guess I could've kept going, and I either would seated the sleeve or stripped the hole!
It sounds like your lower was spread. Mine was too a little bit I did them a little one side at a time like you.. but in the end it was all pulled tight. And torqued down tight. If I put the shaft in my vice I can still pivot the A-arm easily enough on the poly bushings.
-W
Last edited by Clams Canino; Jun 3, 2010 at 11:27 PM.
Melting Slicks
Joined: Jun 2009
Posts: 2,343
Likes: 4
From: Anderson SC
I did the uppers after my last post. You can tighten the bolts until you compress the bushing a bit and the inner sleeve will indeed hit on both ends of it. I gave it a break and then torqued more after 10 minutes to let the bushing "adapt". But yes... once the inner sleeve hits... the bolt gets hard to turn.... real fast.
-W
-W
