Narrowing control arms

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DJ3100

Well-known member
Joined
Sep 4, 2009
Messages
1,899
Location
Chandler, Arizona
My '53 Chevy 3100 has been on the road since "08, but I have never been happy with the suspension. I used a 1980 C10 (1/2 ton Chevy truck) front suspension because it fit the frame and I figured I could do something to get the tires under the fenders. The tires always have rubbed on the fenders.
 

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I have attempted to solve the problem in a couple ways that didn't work, so now I'm shortening the control arms.

I have replaced the 2" drop spindles with stock spindles which will allow the front to drop and get the control arms almost level with the ground and eliminate the bump steer. That moves the tires even farther out which means more rubbing.

I made a model of the suspension and determined that shortening the control arms 1" would have very little effect on the geometry and about 4% change in the force the springs provide. It should also solve the interference problem.

Checking out the parts I will need to remove some metal from the outside of the spring pocket and shorten the tie rod end since there isn't 1" space inside the adjustment sleeve.
 

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I set up a simple fixture so I could measure and realign. I want to keep the same angles and center line and just move the ball joint in 1".

The lower control arms are 1" thick.

I could see I would need to remove the bump stop. Using a 5/16 pilot point drill, the spot welds were drill out.
 

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The lay out. Blue tape is the 1" to be removed.

Cut it with a .035 cut off wheel and finished the corners with an air saw.
 

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The angle is set where it was before it was cut and tacked in place.

Then welded top an bottom. The edges were beveled and the .035 gap was left to achieve a full penetration weld.

About 2 hours later the welds are ground, blended and painted.
 

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Next up was the upper control arms. These have a lot more contour making the layout less straight forward.

Again with a simple fixture. This time the ball joint mount was leveled; a plate bolted to the shaft and clamped to an angle plate kept everything in place.

The layout was more of an eyeball. It was cut the same way as the lower.

Keeping the center line, the 1" dimension and tight on the spacer to maintain the angles, it was tacked in place.
 

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There was a lot of goofing to get the profiles to line up. I pie cut the edge and bumped it in with a hammer and welded it up.

Then with lots more grinding, blending and some paint it is ready to to bolt the ball joint back on and install
 

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I cut about 1/2" off the treads of the tie rod end.

The upper bump stop needed to be cut off and ground to the shape of the stock one.

The lower pretty much just bolted on. These are Energy Suspension bump stops that I got at the parts store.

I ground some clearance in the spring pocket for the spindle.
 

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Maybe I should mention that I have replaced the front springs with air bags a while back. I never really liked the airbags on this truck.

So before I took the front end part I put the stock springs in and drove it a bit. It sat too high and was too stiff. Looking in my pile of parts I found the front springs from the '84 Mustang (F2stang). They were in size close to the C10 springs: Wire .025 smaller, OD .250 smaller, same number of free coils , and 1" shorter. The Mustang is the one with the rubber stuff on it.

They put the ride height right where I wanted it and gave just a bit smoother ride. And they were free!
 

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So, here's some pics of the complete ride. I got big/ little, slight rake and lower front ride height without tires rubbing.

Getting the tie rods level with the ground eliminated the bump steer that has plagued it from the beginning.

It rides good, handles well and I'm happy with the look.
 

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Thanks, I had a good weld sculpting mentor.

I wasn't really trying to hide the modification, as a close inspection will show. But the alignment tech spent quite a bit of time getting it shimmed properly and he didn't know they were modified.
 
great job, when I first read the title I thought this is a bad idea and it is not going to turn out well. I was wrong and should have known better, I think they came out real nice.
 
great job, when I first read the title I thought this is a bad idea and it is not going to turn out well. I was wrong and should have known better, I think they came out real nice.

Thanks, it was nice to have something to contribute.

I was nervous about the idea, as well. When I made a model of the pivot points I could see these A arms are so big (19 1/4" between pivot points) that shortening would only change the pivot to spring ratio by 4% and would have very little effect on camber throughout the travel.

Besides, my next option was to tear out the whole front suspension and replace it with something narrower - seemed worth avoiding if possible.
 
I have pulled the fenders out over an inch. I extended the brace at the top of the fenders and at the bottom rear. I just could not get them to go any more without cutting and adding material. A couple of the pics in post 11 show the reshaped fenders. In stock form they are pretty flat on the sides. I don't think the reshaping is very noticeable or objectionable.

I still needed at least 3/8" more clearance, more if possible.

I also looked for wheels with more back set. I wanted to keep the old school 15" look. I even bought some, but they won't clear the calipers with 11" rotors. Rocket would custom make some $450 each. Or I could have sacrificed the old school look and spent $1500 + on bigger wheels with new tires. I figure I had nothing to loose by cutting the control arms.
 

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