The OE sleeve warps due to large slots, causing the valve to bind up, or leakage occurs due to sleeve wear, resulting in loss of any pressure.
Replace the OE sleeve with the Sonnax sleeve, which provides added stability and better wear resistance.
The OE TCC regulator valve sleeve is prone to warping because of the large slots on both sides of the sleeve. Once warped, the valve binds and gets stuck in one position or leads to excessive bore wear and circuit leaks. The Sonnax sleeve 54754-02 has reinforcement ribs for added stability and is made from wear-resistant aluminum alloy material.