Because... weight savings?

Helped my brother out on a brake bleed gone wrong. Apparently when he went to turn the bleeder screw on this HHR, he suddenly discovered that it wouldn’t tighten anymore, and brake fluid was still dripping. Lo and behold, the threads had stripped.

He pulled the drum off and I saw a glint of blue underneath the brake dust. I wasn’t sure if I should be impressed to see anodized aluminum, or ask what kind of boy racer bling is this? I gotta admit, it does look pretty cool... for a drum brake part that isn’t even visible once it’s all together.

All the wheel cylinders I had seen up to this point had cast iron housings, and were hardly worth rebuilding, since you can get new ones for like $10 all day long at the local parts store. That wasn’t the case here. $30 for a freakin’ wheel cylinder. And even if this one was rebuildable, no rebuild kits were available. AutoZone’s was anodized blue too, so I guess this was a stock part after all.

We got back to the HHR and that’s when I noticed that the bleeder screw in the new one was crooked. Ruh roh Raggy

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False alarm! It’s not cross-threaded after all. It’s actually supposed to have a slight angle. I put it back in with a dab of anti-seize and removed the old wheel cylinder to swap the new one in.

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From then on, everything went smoothly. Even the old fare nut behaved, coming out of the old cylinder without a fuss and screwing right into the new one. I had to be careful about torque, though. The only spec I could find was 144 in-lb for the mounting bolts. I sure as hell didn’t want to strip the line or bleeder again.

In fact, the aluminum made me so nervous that I didn’t even bother touching the one on the other side of the car. I only ran enough fluid through this one to push the air out. Some old fluid was going to have to stay in the lines, at least for now.

So what do you make of these wheel cylinders, Oppo? Why would GM even bother with this sort of thing on this sort of car? Have aluminum prices come down that much? Is it about weight savings? Fuel economy? What’s this all about?