I have a gripe and a small amount of info and looking for any other input. For a long time I have been shopping for a larger oil extractor. Up until now I have been using my small Harbor Freight brake bleeder hand vacuum pump that I rigged up to a 1 qt pickle jar to give me a bit more volume before emptying. I mostly used it to drain the master cylinder and power steering pump and did 1 oil change on the lawn mower that does not have a drain plug. A few months ago I tried using it to change the transmission fluid but after 4 qts I got pretty tired of pumping and started shopping. There are a ton of testimonials out there of how fast they pump the oil out or how slow but I cannot find a single person or review that actually measured the amount of vacuum their extractor developed. Maybe I am missing something but this seems to be a critical piece of information for a vacuum pump. Even the manufacturer does not state this info in their spec sheets, and I could not find another person asking this question. How do you really compare 1 pump against another before you buy. The time it takes is governed by the vacuum and the size of the tube and the length and the head and the viscosity (hot or cold). So without all that info being the same the only relevant spec would be the vacuum. So with my rant over the info I have is that my Harbor Freight hand pump develops a max of 28 inHG and the pump I ended up with OEMTOOLS 5.3 liter hand pump develops 24 inHG. It seems to have a check valve that stops any more vacuum from developing. I just hooked it to my small hand pump so both readings are from the same gauge. I was interested in seeing how much vacuum but also if it had any leaks before my return period ended. It didnt.
So has anyone else bothered or cared to check theirs. I would really be interested if anyone has done this with one that works off an air compressor.
So has anyone else bothered or cared to check theirs. I would really be interested if anyone has done this with one that works off an air compressor.