Single Proportioning Bleeding Tool For Gm Combo Valve Flush ✔️ Aluminum body locks low pressure valve fits PV2 PV4 disc drum setups This handy aluminum swap kit drops straight onto non adjustable GM combination valves to block air from sneaking into the master cylinder while you work lines. Garage crews toss it on old pickups and daily drivers whenever they need to flush out trapped gas or replace cracked hose sections. ✅ Heavy duty aerospace grade construction withstands shop bay impacts ✅ Precision tapered threads seal directly over warning valve ports fast ✅ Metallic blue coating resists grease solvent wear during extended shifts ✅ Simplifies dual circuit bleeding by holding exhaust pin firmly open 💡 Why Does Fluid Keep Backfowing Through Secondary Channels When You Drop The Pedal? Factory engineering pushes primary pressure straight toward rear circuits without proper mechanical shutoffs. Direct swapping gives you firm control over split line dynamics during every service cycle. - Manufacturer geometry moves main force exclusively toward rear axle groups without manual override caps - Direct threading halts backward siphonage while you stroke repeatedly during routine line replacements - Solid internal pins held discharge ports fully open so fresh fluid forces stale liquid out quick - Worn warning toggles peel rubber gaskets which spawns persistent air traps across circuit halves ✝️