my "52 spring swap" expieriance

[mostwanted]

I helped my buddy install springs on his '79 c20 truck today. We thought that they were 52" but may not be. We were a little confused on the method used to determind the length. Do you measure from eyebolt to eyeboly or from the beguining of the curve? Do you follow the contour of the spring or measure strait accross the arch? We followed the article in the technical articles, except we used springs out of a 3/4 ton Suburban. We moved the rear shackle forward and drilled a 2" hole for the bushing and we moved the front hanger foward as suggested, but when we attached the springs, the rear shackle was only a inch or two from contacting the frame. Are these 54" springs? We put the rear shackles back in their stock locations and that added another couple of inches. We are thinking of moving the front hanger forward another 2" on a custom mount. We used the 3/4 ton springs beause the truck has a cummins in it. Surprisingley, with those springs, it appears as if it will still have plenty of flex.

only an inch or two of clearance

will get better pics tommorrow

 

[ryan22re]

probably 56" springs if they came from a 3/4 ton

should measure along the top leaf.

 

[MTMike]

The length measurement is the main leaf's length from eye to eye when flat. 52's measure ~49-50 unladed, 56's measure 53-54

Sounds like you got a set of 56's by mistake

If you want to keep those springs, and you put your shackle hanger back to it's original location you should have better shackle angle, but you may need to modify the body mount so the shackle doesn't bind up on it.

Mike

 

[SCOOBYDANNN]

That pretty funny-------because thats EXACTLY what happened to me. 3/4 sub is 56's. here is my writeup if you are interested. I did put the long side foreward, some/i guess most are putting the long side rearward giving the axle about 4" foreward.

 

[nvrenuf]

An easy check is to see if the center pin is centered in the springs, 52 = centered / 56 = 4" offset.

 

[Art'74]

If you want to get rid of those 56" springs let me know. I've got my 52" for the front ( I even have an extra set off the back of a K5 if you want to swap) and I need the 56" for the rear.

 

[mostwanted]

An easy check is to see if the center pin is centered in the springs, 52 = centered / 56 = 4" offset.

you are correct. For now we are going to leave the rear shackle in the stock location. We may build a custom mount anoher inch or two forward for the front shackle. Our biggest problem was when we bolted the axle up, they were either 2" past center or 4" back.

 

[mostwanted]

If you want to get rid of those 56" springs let me know. I've got my 52" for the front ( I even have an extra set off the back of a K5 if you want to swap) and I need the 56" for the rear.

I think we are going to stay with the 56"s. But I may be wanting them for my blazer this summer