I am sure you could get a crashed cobalt and take the back axel for like 500-600

 

maybe even less! i say go for it!

 

I believe that the HHR actually has a lower curb weight than the Cobalt Sedan.

 

There may also be other parts that need to be replaced. Sometimes the master cylinders are different as it may require different fluid volumes nad pressure for discs versus drums. Also the proportioning/equalizer valves may need replacement or an adjustable one installed. Drum brakes are
"self-energizing", meaning that once they are engaged, they tend to grab harder just from the friction. Disc brakes require pressure proportional to the amount of braking needed - they are not self-energizing.

To get optimum performance from a disc brake conversion, you have to think "brake system", not just "rear brakes".

Steve

 

I did a rear axle swap on a mustang...drum to discs. I swapped out the proportioning valve from the disc brake car as well. I did not swap the master cylinder. The brakes worked fine, but not as well as i thought they should.

 

Actually my HHR weighed in at 3318 with 1/2 tank gas and me in the driver's seat. My friend's SS sedan with 1/2 tank and him driving was 3054. The HHR's are mostly metal and have a big added heft with the rear "wagon" style hatch. To say the HHR is the chunky brother of the Cobalt is speaking lightly.


EDIT:::: Regardless of part number for the pads this does not mean the rotors are different. We could use the same rotors but the calipers may be different due to our heavier body or the SS's highperformance brake setup. Only thing you can do is check and see. Be a guinea pig!