Low spring rates, incorrect spring heights and inappropriate replacements from previous rebuilds can lead to low base line pressure. The Sonnax replacement spring 77917-08 provides a resultant idle base line pressure of 72 psi, and 82-85 psi cracking pressure, which is consistent with the OE orange spring

• The Sonnax replacement spring is stronger than many alternatives, and allows increased pressures throughout the stroking action of the pressure regulator valve.