Help needed! - Identify this control arm - The 1947 - Present Chevrolet & GMC Truck Message Board Network

litew8 · 10-03-2011, 09:49 PM

My truck is confusing me. The truck is a 1971 C20 with 5on5 all around.
So... that means someone (20+ years ago estimated) switched out the original 3/4 ton spindles and rear with C10 parts. So I think....

Does it look like these are C10 upper control arms?
Because look, the ball joints still have the rivets in them.

If these are C10 upper control arms, does that explain why it's shimmed so much?

Thanks for any insight

71swb4x4 · 10-03-2011, 09:55 PM

Doesn't look shimmed too much to me. Could be 1/2 ton control arms.

Have you verified that it's the original frame? Maybe someone body swapped the body onto a 1/2 ton frame after an accident or something.

litew8 · 10-03-2011, 10:10 PM

Yes, the cab matches the frame VIN to be a C20.
I don't see shims like that on other builds. There are like 4 or 5 shims on each bolt.

Is it (shims) to compensate the upper control arm (if it is a C10 upper), to align properly with the lower C20 control arm?
Because I thought that C10 upper and C20 upper control arms are the same other than the ball joint holes.

71swb4x4 · 10-03-2011, 10:21 PM

I just read your other thread, certainly looks like someone went to a lot of work at one time to swap the 1/2 ton suspension over. Looks like they did a good job too.
I still think the shims are fairly normal, but I am not a suspension expert.

**lolife99** · 10-03-2011, 10:23 PM

Upper control arms are the same,... with a different install ball joint.

Lowers a-arms are a different a-arm all together.
(3/4-ton has a larger ball joint hole).
The dimensions of the a-arm length are the same.

Those shims don't look excessive to me.

litew8 · 10-03-2011, 10:25 PM

Okay, so they must be upper control arms from a C10? - since the ball joints haven't been bolted in?
And C10 lower control arms to fit the spindle?

The driver's side lower ball joint has been destroyed for a long time now. I bought C10 ball joints (all around) to replace, hope it all pans out right.

Thanks 71 and Keith

**lolife99** · 10-03-2011, 10:47 PM

I think at some point in time,... someone swapped all the C10 parts (from a donor truck),... to your truck.
The frame itself is the only thing that is C20.
(whiich isn't that different from a C10 frame)

20 years ago you could swap parts without replacing the ball joints and other suspension components,.... because you could still find them in good used condition.

I wouldn't worry about it.

litew8 · 10-03-2011, 10:50 PM

Thanks Keith. Not too worried about it, only I need to understand what parts to buy for - a C10 or C20.

The only other thing I've bought so far are bushings for the sway bar, for a C20.
I'm thinking it was a conversion done on a farm, or a really good rual mechanic.

I agree 71, nice job indeed - especially since it was done before the internet and this site!

10-03-2011, 09:49 PM	#1
litew8 Registered User Join Date: Jul 2011 Location: Des Moines, Iowa Posts: 3,016	Help needed! - Identify this control arm My truck is confusing me. The truck is a 1971 C20 with 5on5 all around. So... that means someone (20+ years ago estimated) switched out the original 3/4 ton spindles and rear with C10 parts. So I think.... Does it look like these are C10 upper control arms? Because look, the ball joints still have the rivets in them. If these are C10 upper control arms, does that explain why it's shimmed so much? Thanks for any insight __________________ project: "my happy mess" Last edited by litew8; 10-03-2011 at 09:55 PM.

10-03-2011, 09:55 PM	#2
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: Help needed! - Identify this control arm Doesn't look shimmed too much to me. Could be 1/2 ton control arms. Have you verified that it's the original frame? Maybe someone body swapped the body onto a 1/2 ton frame after an accident or something. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

10-03-2011, 10:10 PM	#3
litew8 Registered User Join Date: Jul 2011 Location: Des Moines, Iowa Posts: 3,016	Re: Help needed! - Identify this control arm Yes, the cab matches the frame VIN to be a C20. I don't see shims like that on other builds. There are like 4 or 5 shims on each bolt. Is it (shims) to compensate the upper control arm (if it is a C10 upper), to align properly with the lower C20 control arm? Because I thought that C10 upper and C20 upper control arms are the same other than the ball joint holes. __________________ project: "my happy mess"

10-03-2011, 10:21 PM	#4
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: Help needed! - Identify this control arm I just read your other thread, certainly looks like someone went to a lot of work at one time to swap the 1/2 ton suspension over. Looks like they did a good job too. I still think the shims are fairly normal, but I am not a suspension expert. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

10-03-2011, 10:23 PM	#5
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Help needed! - Identify this control arm Upper control arms are the same,... with a different install ball joint. Lowers a-arms are a different a-arm all together. (3/4-ton has a larger ball joint hole). The dimensions of the a-arm length are the same. Those shims don't look excessive to me. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

10-03-2011, 10:25 PM	#6
litew8 Registered User Join Date: Jul 2011 Location: Des Moines, Iowa Posts: 3,016	Re: Help needed! - Identify this control arm Okay, so they must be upper control arms from a C10? - since the ball joints haven't been bolted in? And C10 lower control arms to fit the spindle? The driver's side lower ball joint has been destroyed for a long time now. I bought C10 ball joints (all around) to replace, hope it all pans out right. Thanks 71 and Keith __________________ project: "my happy mess"

10-03-2011, 10:47 PM	#7
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Help needed! - Identify this control arm I think at some point in time,... someone swapped all the C10 parts (from a donor truck),... to your truck. The frame itself is the only thing that is C20. (whiich isn't that different from a C10 frame) 20 years ago you could swap parts without replacing the ball joints and other suspension components,.... because you could still find them in good used condition. I wouldn't worry about it. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

10-03-2011, 10:50 PM	#8
litew8 Registered User Join Date: Jul 2011 Location: Des Moines, Iowa Posts: 3,016	Re: Help needed! - Identify this control arm Thanks Keith. Not too worried about it, only I need to understand what parts to buy for - a C10 or C20. The only other thing I've bought so far are bushings for the sway bar, for a C20. I'm thinking it was a conversion done on a farm, or a really good rual mechanic. I agree 71, nice job indeed - especially since it was done before the internet and this site! __________________ project: "my happy mess" Last edited by litew8; 10-03-2011 at 11:08 PM.



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