Quirky one... I was cleaning up the Air cleaner assembly on my 68 Cat yesterday -- trying to get it ready for some paint. I removed the two vacuum hoses underneath, that connect the temp sensor to the control damper on the air horn. Both appear to be original. After some clean up I determined that the hose that pulls vac from the carb to the temp sensor "input" side is completely blocked. I thought it might be mud bees or some such thing. However, after inserting a wire I can tell there is something inside the line -- hard as a rock. If I didn't know better I would say it was steel -- Can anyone suggest why this would be the case? I figure I should just swap in a fresh piece of hose but it was so odd that it almost seemed intentional??