This left-hand spring applies downward force to the coulter arm of a grain seeder, maintaining consistent soil penetration depth across the working width. It connects the coulter linkage to the press wheel assembly; the spring tension counteracts the upward lift from the soil surface as the coulter travels through the seedbed. A sagging or broken spring reduces coulter pressure, causing uneven seed placement and shallow coverage in harder soil. The manufacturer machines the spring to the original free length and coil count, so the preload on the coulter arm matches the factory setting without additional shimming.