how often do rear coil springs go bad?

[theastronaut]

Originally Posted by 64stpside

If I hit a bump in the road taking a sweeping turn at say 40 mph, the rear feels like it struggles to keep contact. It's not a violent reaction but noticeable.

That's normal for a straight axle, and its worse for trucks with very little weight on the axle. Softer springs will help the truck absorb the bump better without it "hopping" over it as badly. I've watched the rear end of stifly-sprung solid axle Pro-Touring cars bounce over mid-corner bumps on an autocross course, part of it is the high spring rates and part of it is the solid axle's inability to conform to the road source as well as independent suspension.

A huge part of the problem with a truck is that the percentage of sprung (weight that the springs support) vs unsprung weight (axle, wheel/tires) is at a really disadvantaged ratio compared to a vehicle with a more even weight balance front to rear. That's half the reason why they ride better with weight in the bed. There's not enough sprung weight to keep the unpsrung weight settled and under control.

I'm pretty sure that the factory coil springs are dual-rate. Check to see that the center part where the coils are closer together still have daylight between the coils at normal ride height with no load in the bed. If they've sagged any and the coils have closed up then you're riding on the part of the spring with a higher spring rate and it'll ride rougher.

C10's had the option of standard or HD springs, yours may have the HD springs from the factory. Another option is to replace the coil springs with Airlift D2600 bags. They won't need much air pressure to pump up to ride height since it's a larger bag so the spring rate will be lower. A sway bar won't help with the bouncing/skipping effect; if anything it'll make it worse.