For consistent performance, the Forge (supersize) diverter valve needs to be regreased occasionally. In order to do so, you need to remove it from the car, twist open the end cap and regrease the O-rings. Here’s how:
Required for this service:
Gloves (optional, but useful)
Towels/Rags/Something to clean up grease with (something you can throw away, don’t use the good stuff)
Mobil 1 Synthetic grease (Forge’s recommended grease)
Ratchet and socket or screwdriver to remove clamps
Step 1. First remove the valve from the car. Remove the clamps holding the valve to the silicone tubing. I used a 1/4″ ratchet with a 6mm socket for the clamp. Your hose clamp size may vary so don’t go out purchasing the socket. Unplug the vacuum hose from the boost tap as well.
Step 2. With a firm grip, unscrew the top/other half/whatever of the valve off. This may take some force if it’s your first time doing this service. You’ll notice that there is an O-ring in the main body. Or at least it should be in the main body. Sometimes, it gets stuck in the top portion. Remove and place it aside.
Next, push the piston up and it should slide out the open side. Do this on a towel so you don’t drop the piston when it pops out. Now you should have the 4 main pieces. The top half, the main body, a spring and a big ol’ piston. There are 2 o-rings in the main body. Remove them and clean them. A simple wipe of a rag should do. You should have 3 o-rings in total. 2 from the main body and 1 from the top half seal. Anyway, clean out all the grease and oil from all the parts and set aside.
Step 3. Now get your grease, and apply a thin film to where the piston o-rings should be. Then place the o-rings in place. Between the two o-rings, place another thin layer of grease. Apply a little to the area behind the o-rings as well. You don’t want to over do this. Take the cleaned piston and line it up as best you can. It takes a little shove to get it past the o-rings. Once it’s in, push it closed. Place the spring back in. I usually dab a little grease on the contact points of the spring but I don’t know if it’s really necessary.
Place the 3rd o-ring in it’s little groove along with a thin layer of grease. Be careful with this ring, it seems fragile. If you need replacement o-rings, just contact Forge.
Now just screw the two pieces back together. You don’t need a lot of force, just snug them up.
Step 4. Replace the valve in the engine bay, connect the hoses and clamps, and don’t forget the vacuum hose. Now drink a beer and marvel at your awesomeness.