One of the two (non-metallic) shims in the rail clamp has separated (ie has come unglued) from the inside of the 'half tube' on the clamp.
Having no technical knowledge about adhesives that I might use to keep this "little red sucker" in its proper place and prevent it's loss (I seriously doubt Linhof has replacement parts for this old but still serviceable and wonderful but overweight piece of equipment... )
Can anyone suggest an available product to cure my problem?
When I bought my Linhof (1992), they advertised the promise to keep in stock all replacement parts for at least 22 years.
My brother had an 'old' Technica IV, and Linhof still had parts for it in the late 1990's!
I would not be surprised that they still have the part you are looking for, just mail them.
Include a picture of the part and the serial number of the camera.