Pretty doubtful that anybody has used the sap from a rubber tree in automotive parts for over 60 years.
My dad used to tell about a time when he was a kid in the mid 1920's. They had a big family gathering at the farm one summer weekend and there were probably a half dozen of his cousins there about his age. They were playing around over by the barn and one of them grabbed up an old inner tube that grand dad had just patched. One of the older boys said , "I'll bet if we pumped that full of water and poked it with a pin it would shoot water in the air 50 feet."
They all thought that was a fine idea and something they had to see. My dad knew where there was a hand pump and somehow they got it hooked up to the tube. He said, "We must have pumped more water in that old tube than would fit in a wheelbarrow. When we finally decided it was full enough, it was stretched so damned thin you could almost see through it."
He went in the house and got one of grandma's hat pins and all the boys gathered around to see the jet of water squirt 50 feet in the air.
When he bent over and poked that pin in the tube they all got a big surprise. It didn't shoot a stream of water in the air, it blew up and drenched everything and everyone within 15 feet.
There wasn't a piece of that tube left big enough to cover the palm of your hand. They all had a big laugh about it, but he wasn't laughing so hard when grand dad went looking for his only good inner tube. Said he couldn't sit comfortably for a couple days.