Thanks to Fab for posting this on the CLC forum

just rebuilt my entire heater system about 3 or 4 months ago. To remove it, you need to do the following:

1. Unhook the electrical connections under the dash. I think there are only two wires, a fused power source, and a wire to your underseat heaters.

2. Detach the two control levers.

3. Unscrew the metal bracket holding the thin copper capillary tube in place.**

4. In the engine compartment, remove the heater hoses from the bottom of the unit.

5. Remove all the bolts attaching the unit to your firewall. There’s a rubber gasket between the heater unit and the firewall. Mine had somehow sealed the unit to the firewall, so I had to pry it off. (You can buy a replacement here: http://www.steelerubber.com/heater-gasket-70-0448-31)

6. Once you get everything removed and the unit free, start to pull it out gently. You’ll see a vent cable attached to the side of it. Unscrew and release this.

**MOST IMPORTANT THING: make sure not to pinch or break the thin copper capillary tube. If you damage this, your heater valve will be useless. Best to have somebody on the inside helping guide the unit out.

Once you get the unit out, you can remove the two heater valves. I sent mine to Jim Tucker: http://www.heatercontrolvalve.com/. I think it was about $250 to rebuild both valves.