The Toyota Yaris is the smallest car sold by Toyota in the North American Market. It was designed primarly to sell in third world markets, but Toyota brought it over to America to sell to younger customers. However, the vast used car market in America has largely dampened their sales. The Toyota Yaris uses indpendent spring suspension in the front and torision beam suspenion in the rear. The springs in the front can go bad over time and need to be replaced.
Park the Toyota Yaris somewhere flat, like a garage or driveway. Put the car in park and engage the emergency brake. Jack up the front two corners of the Yaris and slide in the jack stands behind each front wheel well. Take the front wheels off with a tire iron and place the wheels to the side.
Unbolt the bottom two bolts of the front spring strut from the top of the steering knuckle. Then unbolt the top two bolts from the top of the strut. Pull the strut out and then lay it down in front of you. Use a vice to compress the spring so that it does not expand. Unbolt the top spring cover from the strut and then slide the strut out from the old spring. Compress the new spring with the vice, slide in the strut, and reattach the top spring cover on the strut. Repeat this procedure on the other side.
Bolt the tires back on and lower the Yaris down from the struts. Turn the sedan on and take it for a test drive. The new springs should give a stiffer ride than before, but it should not be uncomfortable to drive.
Do not perform this install on the side of the road where traffic may endanger you.