Intro: friends 74 (really, it's not mine), been sitting for years, I'm helping him get it drivable again.

The air pump seems to be frozen. The pulley won't turn. As he's planning on registering it in DC where they check emissions, I assume I can't remove the pump.

Can these things be rebuilt or is there a quick fix for unfreezing the pulley? Or is replacing it my/his only option?

 

Try finding a good used one... like this one if it looks the same:
Napa 51 112 Pump Smog Air Pump | eBay

Apparently you can buy rebuilt ones for about $150.

 

Emissions on a pre-catalytic converter car? That system was so poor it did almost nothing once the choke opened up. My guess would be it just needs to look like it works. I find it hard to believe a modern exhaust sniffer could pic up the difference on a warmed up car.

I thought only California messed with pre 1975 emission.

 

The air pump has no effect on emissions with a hot (running temperature) engine, which is how you want it when tested. If all your state does is a tailpipe sniffer test, then you can bypass/remove the pump. But if they also do a visual under hood equipment inspection, then you'll need to keep it. The last pre-96 car I had sniffer tested was a 91 Camaro. They used the mirror on a stick to check for a cat, but never opened the hood. What other states may do will vary, but here they were only focused on pass/fail, then on to the next car.

 

I was just watching a behind the scenes of Roadkill (my favorite internet show) and they made the comment. "here in California we only look at pre 1975 cars because they are all exempt from any emission requirement." That is California where car manufacture had special California emission packages in pre 1975.

When you look at how few car pre-75 are used as daily drivers and how little those pre-cat emission system did it can not have more the .001% effect on the environment. At this point DC is just making money on you.