Bicycle Mechanics - How do I release a side pull brakes?

I was changing the tubes on a 1980 Raleigh 5 speed with side pull brakes. These are the original brakes. When I went to reinstall the wheels, I could not figure out how to release the brakes, so I let the air out of the tire so I could get it past the brake pads. There is a spring wire that runs from one side of the brake to the other, and I tired releasing that wire, but it didn’t seem to do anything. Can anyone help me? I got the wheels on the bike, but I’d like to know how it is supposed to be done. Thanks in advance!

All my side pull brakes have little cam by the end of the cable and when I turn it about 1/4 of turn, it opens up about quarter of an inch. I think yours have too, look for it. Having said that, even it opens up a little it's still not wide enough for any size tire but smallest I have(700x20c) but even then, barely. There maybe a better way to do it but I have convinced myself it's just a part of the process to release the tire pressure before I take the wheel off. Let's wait and see if somebody going to post a better idea.

Lacking a quick-release mechanism on the brake caliper's anchor bolt or on the brake control lever, deflating the tyre is your best option, as it certainly beats temporarily removing a brake pad.