I am having difficulty making the dash heater work properly. It is very difficult to control the amount of heat. It is either full on or full off. I think the problem is that a bushing is missing from the lever on the control device for the hot water. The following picture shows the control device. Does anyone know where this may have come from and where I could get the missing part(s)?

Working the dash board lever should actuate that valve, & vary the water flow depending on the position of the dash lever, thus varying the amount of hot water that goes through your heater core.

As you move the lever on the dash, the rod that rides in that angled slot on the valve, should move through the slot, actuate the valve on the other end of it, & vary the water flow.

Have someone exercise the dash lever while you observe what happens at the valve. You may spot your problem immediately.

It sounds like, for some reason, your valve is either full open or all the way closed. Those valves do fail. I replaced mine with a generic from an auto parts store. Find something that will fit the configuration of your water hose & actuation cable, & replace it. Just be sure the configuration is such that moving your dash lever to the right, will open the valve.

SIDEBAR: If the control cable ends up being part of the problem, here's a good source for custom-made replacements:

http://www.rayeveritt.com/Heat...es/HeaterCables.html