Front & rear suspension for 1955-1959 Chevy trucks

CD,
your line is pretty close though it's probably actually closer on th spindle end to where the balljoint enters the spindle. i tend to go with the theory on most any set up to set the leveled lower control arm either at 0 degrees or at downward 1-2 degrees. if you go with downward 1-2 degrees and it's a touch high in the end half a coil will probably it where you want afterwards.

and in most i've seen your up/down travel should be about 1/3 down and 2/3 up maybe closer to 40%-60%..

 

Thanks for your input! I loaded another picture, this time with a red line. If I am reading you correctly, then I should make the "red" line level. I believe that is what mean by the "balljoint enters the spindle. Perhaps that would likely give me the 1-2 degrees downward like you stated.

 

I think you have the spindle up way too high. As he said, you want about twice as much "bounce" travel, as "rebound" travel. That means the distance between the frame and lower arm snubber would be twice the distance between the frame and the upper arm snubber.

 

Okay.... Sounds like a plan. I will lower it and do some measurement of the snubber vs frame distances. Great info! If anyone out there has some pictures of their work, I would greatly appreciate it.

 

i think when you drop the arm down to match the appropriate travel the red line is going to "intersect" with the yellow and gonna look more like what i'm thinking is probably gonna be pretty damned close to the plane you are looking for.from the pics and that cross section of two lines i think your lower a arm is probably 1/2-1" UP from where it should be. hard to throw guesses from pics but if were me i'd drop it a 1/2" and if that wasn't enough go anothe 1/2"....

 

I have delt with many subframe jobs, some I installed and many after the fact. I don't realy like Camaro clips because of their geometry. The upper control arm when at ride height slopes down to the outside so when you go around a corner the tire cambers in the wrong direction. The second gen sub is front steer and interferes with the core support when trying to lower it enough during install. The first gen sub works better for going ultra low as it is rear steer.

Jim Meyer Racing sub is a combo of GM spindles and a rack and pinion that does not replicate the lengthening tie rods that GM used to keep correct ackerman in a turn causing severe tire scrub as the outer tire is turned sharper than the inner one.

A Mustang II based front has correct geometry and works well. There are kits that use C6 Corvette parts that work well. Art Morrison makes good stuff. Understand front end geometry before you chose. The GM stuff works but suffers from under steer. Hope this helps Jim Ford

 

Ive done Camaro clips and they are an improvement. But the Corvette system front and rear is unreal in the comparison.

 

i sent you a PM. i might have what you need.

 

Thanks again for your help. I will need to see how much (in the center of motion area) that the vertical movement affects the for/aft movement.

After much thought... It would be great to know actually the "axle center-line" of the first gen (rear steer) clip. I read a lot on the HAMB about the late 5os GM truck subframe stuff using a second gen (front steer) clip. Most seem to use the upper shock mounting hole as the center-line. Some say to use the "rear" of the upper shock mounting hole.

My question is: What is the reference is used for the axle center-line install of the clip on the 49-50 Mercury? The above picture might not be accurate, just using it as a reference for the question...

Thanks in advance!

 

That's what I'm undertaking right now. A C5 suspension, front and rear, under a '55 Chevy 1st series. I'll let you know how it handles once I'm done butchering 2 vehicles. But that's a thread for the Dogfight forum.

 

...you can tell by your pic with the yellow line the shock top is NOT the centerline of the wheels,....set the sub so the front frame horns are level, or the top A-frame pivot bar is at about 7 degrees tilted to the rear, then plumb strate up thru the center of the grease cap and transfer this line acrss the top of the upper A-frames, (aprox. 2 inches behind your yellow line).
Always tack weld your clip onto the frame, then mount a wheel and hang a fender to verify that it looks rite.

 

When doing sub frames it is easy to get the wheel base too short. The problem is most people don't measure the original wheel base before removing the front sheet metal and engine. If the leaf spring shackles are in the front then the axle moves to the rear as the weight lifted off. Sub frames on the other hand move forward as they are unloaded.

Both the original and sub should be measured at ride height. If they are measured unloaded and then welded on like that the wheel base will be about 2 inches short. It is better to error on the long side than short. On some cars the factory wheel base was too short so set a tire in the wheel well at the height you want in the end and make sure it looks right. Jim Ford

 

I added roughly 1 5/8" to the wheelbase of my '56 and really like the outcome!

 

55willys: Thanks.

I have the luxury of having a complete car sitting on its frame and another complete frame that I can cut up and work with. So getting measurements there is easy! The sub, unfortunately, is alone and I don't have the benefit of being able to load it up. That is why I was seeing if "leveling" the control arms is the ride height. I will have to hit some car shows and take some measurements. Like most tell me, I will just have to experiment and put the body/motor/sheetmetal weight on the mock up before final welding to get it centered in the fender. I figure that is the only way to make sure. I was just hoping to finish the complete job before doing the transfer.