It is important to regularly service your valves to keep them in good working order. These instructions relate to the Forge dump valve BOV (FMDV004) and Forge recirculating diverter valve (FMDV006) for Saabs...

1. Remove the valve from your car and place on a flat surface on some newspaper.

2. Using an allen key carefully remove the valve top, making sure you keep adequate pressure on the top of the valve to keep the spring contained (it can fly across the room!).

3. Remove the spring, piston and components (o-ring and spacers if applicable) from the valve and clean with a cloth, removing all old grease.

4. Add new high pressure grease to components including the screws.

5. Check components move freely and the valve is working correctly. Using a screwdriver push the piston upwards against the spring and place your finger over the top nipple to form a seal. Keeping your finger tight against the hole release the spring and check the piston stays in place. Remove your finger and check the piston moves back OK.

6. Refit the valve top by adding the screws evenly (opposites) keeping the internal spring straight.

7. Fit back on your car and test drive.

If you find idle is not steady or hear a fluttering (compressor surge) it could be that your spring is either to strong or too weak. When buying a new valve always check the spring colour supplied in the valve!

If you increase the PSI of your engine use the Forge tuning kit (FMDVTUN) to keep your Valve holding the correct boost.

Valve Spring color coding (estimate guide only):
Green - 5-15 PSI
Yellow - 15-23 PSI
Blue - 23-30 PSI
Red - 30 + PSI

Spacers can be used to further tune your valve.

Read more about Dump Valves and Diverter Valves here