KMCloonan
Member
In the summer of 2020 I bought the Harbor Freight Pittsburgh 2.5 CFM vacuum pump. I've used it maybe 20 times over 2 years, to stabilize punky woods, blanks, etc. I Changed the oil a couple times, but I noticed the drain plug was difficult to reinsert after draining the pump. Then, recently, I noticed some leakage from the drain plug.
This evening I unscrewed the drain plug, drained the oil from the pump, then turned the pump upside down so I could see into the drain hole. I think I figured out why it has been wonky to reinsert the drain plug - THERE ARE NO THREADS ON THE DRAIN HOLE. The walls of the hole are smooth. The drain plug screw has threads, but there are no mating threads to hold the plug in place. I don't think I ever exerted enough torque on the drain plug to completely strip away the threads. The threads on the plug seem fine. The O-Ring on the screw looks ok too. As far as I can tell, the screw was just jammed into the unthreaded hole, and I have been lucky it did not leak sooner.
Has anyone else experienced something like this? I would have thought the drain hole would have been a harder material, and the drain plug would be softer, so if there was wear, it would be on the plug, not the pump. I don't know about using a tap to create threads - I think that would create metal shavings that would cause other issues.
Worst case, I'm out $100, and I go buy a better quality pump, but if there is a simple fix, I would be interested in giving it a try.
Thanks for any advice.
This evening I unscrewed the drain plug, drained the oil from the pump, then turned the pump upside down so I could see into the drain hole. I think I figured out why it has been wonky to reinsert the drain plug - THERE ARE NO THREADS ON THE DRAIN HOLE. The walls of the hole are smooth. The drain plug screw has threads, but there are no mating threads to hold the plug in place. I don't think I ever exerted enough torque on the drain plug to completely strip away the threads. The threads on the plug seem fine. The O-Ring on the screw looks ok too. As far as I can tell, the screw was just jammed into the unthreaded hole, and I have been lucky it did not leak sooner.
Has anyone else experienced something like this? I would have thought the drain hole would have been a harder material, and the drain plug would be softer, so if there was wear, it would be on the plug, not the pump. I don't know about using a tap to create threads - I think that would create metal shavings that would cause other issues.
Worst case, I'm out $100, and I go buy a better quality pump, but if there is a simple fix, I would be interested in giving it a try.
Thanks for any advice.