I have a "Four Uncles" 6,5L oil extractor that I got from Amazon in August '23. I have only used it twice, the second time being today changing the oil on the 535d. While using it, when the oil was being suctioned out, and I was giving the handle a pump every so often, the handle stopped going all the way down. It hits some sort of internal hard stop when it's half way down. It cannot be forced to go all the way down. I have no idea what might have happened. Any clues? It's basically unusable like this.