Started fettling one and found the pump chamber is jammed. A long lever i.e. big spanner not working. Any suggestions please Also would heat help? Thanks in advance
The issue with heat is that enough to make a difference is likely to melt nearby fittings. Nothing wrong with some warming and cooling cycles if you're careful though and you're not trying to preserve an original finish. I must admit that my method with difficult removeable pump tubes is to use a good quality 6-point socket with an impact screwdriver (not a big impact gun). It might sound coarse and drastic, but loosening fastenings by impact rather than leverage has advantages on something as fragile as a brass tank.
Many thanks for the information, I have a socket that fits but the socket arm is sin the bottom of a shed i am trying to clean out
Apply a good penetrating oil (not WD 40) around the nut at the top of the pump tube. Let it sit for a day then apply more, repeat for a few days. Then either use a 6 pointed socket and an impact driver or a wrench (spanner) of the correct size and an accomplice. Have someone hold the tank so that you can hold the wrench in place with one hand and using a soft faced hammer (lead, plastic, rubber or leather) smack the end of the wrench smartly. As mentioned above, percussion will work much better than a slow application of force. If you are using a socket that is made like a tube with a different size at each end and holes for a tommy bar, scrap it and get a proper machined socket. The stamped ones are not sized to a close enough tolerance and you'll round over the brass nut on the pump tube. Then you are well and truly screwed.
Penetrating oils don't make things easier to break free, they can only help reduce friction once a threaded fastener is actually moving, at which point penetration will be instant, so don't worry about leaving things for days. That would only be relevant if the liquid was actually dissolving oxides or other compounds adhering the threads together.
My experience differs from this. Warm chemical reaction actually works. I agree with @cottage hill bill
What would the chemical reaction be? Disolving of brass oxides that would increase resistance to movement, or dissolving deposits from fuel? Surely in terms of the initial torque to cause the first movement (which will be when it is highest and likely to cause damage) these are only going to be tiny factors compared to the friction between the threads under tension?
I have a socket which seems to fit tight, I know this is metric, any idea what imperial size the nut would be? Have some gun oil which i can use
Gun oil is not a penetrating oil and will not help you here. Mix equal amounts of acetone and automatic transmission fluid (what kind doesn't matter), shake well and apply. Or buy a small can of purpose made penetrating oil such as Kano Kroil. In most cases penetrating oil will seep into the threads. The oil reduces friction between the moving parts. While the tolerance on most commercial/production threads are not tight enough to prevent some amount of space occurring between the threaded parts, that space is small enough that it takes the oil a while to seep into it. I don't think the Hurlock uses metric parts.
