I recently bought new coil springs for my 79 F-150 2wd and once I took them out of the box I noticed that one is about 3/4 inch taller than the other, is this normal? Are they left and right and if so which side gets the taller spring? They have the same number of coils (9). Do they have different spring rates if they are different height? Or should I just return to the Napa store where I bought them and ask for new set? Some help or info about this problem would be appreciated.

 

Need more information to decide that stuff. ;)
What's the wire sizes?
Got a .001" reading caliper or micrometer?
The passenger/right side of the pickup theoretically has more weight.

http://www.panix.com/~alvinj/file12/frame-Ford_Six.jpg

These have nine turns each too...
http://www.panix.com/~alvinj/file12/coilsprings.jpg
Big difference in those two springs. ;)
They will both mash down to about the same ride height tho.

http://www.panix.com/~alvinj/file12/rideheight.jpg

Alvin in AZ

 

1979 F150 2WD

The wire diameter of the coil springs depends on the springs load rate, and whether the truck is a Super Cab...or not.

Some coil springs are the same R/L and have the same wire diameter.

Some coil springs are not the same R/L and have two different wire diameters.

1979 F150 front coil spring wire diameters, if one side is larger than the other, it pertains to the right (passenger) side:

.639 ~ .639 // .718 ~ .718 // .718 ~ .639 // .767 ~ 7.18

 

The truck is a regular cab 351m automatic with a/c.

 

There are FOUR different load rates, EIGHT different springs for this application, it all depends on what springs you have now.

Look on your old springs for color bands. There may be one, two or three.

The bands are about 3/4" in diameter. Note the color of each.

One spring could have...for example... one purple band, or...one purple and green band, or...one white and purple and green band.

This is how Ford enabled us NumberDummy's to ID what springs were on the vehicle.

In 1983, Ford did away with this foolishness, listed spring codes on the Certification Label.