Drain Plug thread size
Posted: Fri Nov 15, 2019 8:57 pm
Hi,
I have just removed the drain plug from my Major to drain the engine oil. Looks like the plug has either been cross-threaded in the past or is of incorrect thread pitch as the thread is in a poor mashed state. The plug looks like its made of brass and has a square head with flange (it almost looks like a end stop for plumbing?). I want to replace it with a new plug and want to make sure the size is correct also I want to get a thread tap to retap/clean the thread in the sump (just in case). Measuring the diameter of the plug (not the hole) it looks like a 3/4 inch diameter with thread pitch is about 2.3mm per turn (I measured 7mm for 3 turns) which is close but not quite a UNC thread pitch (2.54mm). When I go on line to see if I can get a drain plug for a major they are all 7/8 UNF threads with a hex head. https://www.agrilineproducts.com/sump-plug.html. Does anyone know what the correct engine drain plug should be for a 1957 diesel major E1A?
I have just removed the drain plug from my Major to drain the engine oil. Looks like the plug has either been cross-threaded in the past or is of incorrect thread pitch as the thread is in a poor mashed state. The plug looks like its made of brass and has a square head with flange (it almost looks like a end stop for plumbing?). I want to replace it with a new plug and want to make sure the size is correct also I want to get a thread tap to retap/clean the thread in the sump (just in case). Measuring the diameter of the plug (not the hole) it looks like a 3/4 inch diameter with thread pitch is about 2.3mm per turn (I measured 7mm for 3 turns) which is close but not quite a UNC thread pitch (2.54mm). When I go on line to see if I can get a drain plug for a major they are all 7/8 UNF threads with a hex head. https://www.agrilineproducts.com/sump-plug.html. Does anyone know what the correct engine drain plug should be for a 1957 diesel major E1A?