[TestDrive]

Edit note. After posting, I saw pictures of spring in other thread. Disregard questions about variable rate springs.

Originally Posted by bennelson

I was able to remove the rear-left spring from the Geo.

Is the upper spring seat a separate part removable from car like in the diagram? If so, you might get more accurate (inner minimum, outer maximum) measurements for new spring off of that part. Take a good look at that location, the sheet metal of the unibody might want some reinforcement there. (Almost more likely than the suspension arm to need beefing up.)

Might be better if you measured the spring stock diameter with a cheap (vernier metal/plastic dial) calipers. But just over 1/2" but less than 9/16" will probably satisfy guys at spring shop. They'll most likely use heavier stock anyway.

Are the coil windings the same distance apart - a fixed rate spring? If so your 1.5" / 140 lbs spring rate works. Other wise it's a variable rate spring. eg.

1. First 140 lbs spring compresses 1.5"
2. Second 140 lbs spring compresses 1.25"
3. Third 140 lbs spring compresses 1".

Or variation there of.

Have no real idea, but now that you've got spring dimensions, maybe it's worth a trip to the salvage yard to attempt to find cheap HD replacements. If longer but essentially otherwise the same is a choice, consider what the clearances were like getting the old spring out. The previously mentioned metro front springs might be a good option (or a total nightmare depending).