I think I need rear springs and bump stops for my 2010 hhr. The rear hits bumps really hard. Does anyone know where I can get good inexpensive parts?

 

RockAuto

https://www.rockauto.com/en/catalog/...il+spring,7512

https://www.rockauto.com/en/catalog/...ump+stop,19119

These might be what you’re looking for. You might have broken rear coils springs, look at the lower portion of the rear springs and check your rear shocks for fluid leaks.

 

How can I be sure if I need one or the other or both?

 

Bad shocks will have oil seeping out of the top of the shock body, a broken spring will be, well broken.

Have a look in this thread picture in post #1

https://www.chevyhhr.net/forums/prob...-spring-58583/

I would change shocks and springs, however your description of the problem indicates the shocks aren’t doing their job

 

If the shock have more than 75,000 miles they are worn out. The swing axle has rubber bushings that have been known to wear out; diagnose them with your mark II optical sensors.

 

Just push down on the rear of the car it should come up and stop.... if it bounces like a pogo stick your shocks are bad. If the springs are bad the car will sag, possibly one side lower than the other but the rear will definitely be lower than the front if springs are bad or broke. If the car is bottoming out over small bumps springs are definitely bad or broken as nothing should make it contact the bump stops unless you got a lot of weight in the back or towing.

 

See my latest post.