This is a spin off from my question about a Tilley X246B Mk I that was pulsing (here:Pulsing Tilley X246B Mk I). I think I have got to the bottom of that but seem to have found or created another problem in the process. As it is a separate issue, it seemed best to start a new thread. In summary, I can’t now seem to maintain any pressure. On close inspection the leak seems to be through the pump, i.e. the non-return valve is not doing its job properly. The NRV washer (pip) and spring seemed in reasonable condition, if quite hard, though there was a circular indentation where the projecting valve seat had been against it; so it may not always have been that hard. By the way, the washer is the type that is square with a round projection to attach to the spring. Now: I have a Tilley SP1 kit (from the Tilley UK website shop), which included both springs and washers. However, the washers included in the kit seem as hard, if not harder than the old ones! I continued anyway, but failed again as I anticipated. I’ve looked at the valve seat as well and as far as I can tell it seems level and undamaged. It seems clear to me how the NRV works and what’s failing with the valve-seat pressing against the flat hard surface of the washer and failing to seal against the back pressue, but as the (new) replacement NRV washer also leaks where do I go next? Could it be that the Tilley sent me old and hardened washers? To give an idea of the hardness of the washer, pressing my nail into the side (not the face), barely makes an indentation. Is this to be expected or a sign of old stock? I'm also now wondering if this is yet another aspect of the X246B's problematic design and character? I would be really grateful for any thoughts.
Is the seal holder, the square piece, free to slide in the retaining sleeve? Check there is no dirt in there. The washers should not be hard but the consistence of medium rubber. (difficult to be more descriptive). I have succeeded to sorth this problem by slightly stretching the spring but go steady as if you over stretch it pumping will be difficult. Ensure the retaining sleeve screwss in fully to the pump body. If that fils then get some viton washers from Fettlebox as these have never given me any trouble. Oh, one other check ... the part of the nrv with the valve seat is soldered into the pump tube. Check there is no leak there.
To prove the NRV out, one way is to pump up the lamp when totally empty, remove pump stem with leather cup and all and put a little water down there. You should see bubbles if it is leaking. You will have to pump a fair bit as there is no liquid fuel to reduce the volume. You can see if the bubbles are coming from the centre (valve seal) or from the edges (solder failure). good luck C
I use the suck method. Remove the pump plunger and place your mouth over the pump shaft and suck. If the NRV is working correctly you should maintain a vacuum until you release your mouth/tongue. It sounds a bit tasty, but it’s a quick and sure way of testing the NRV ...... even if you taste a little kerosene. Cheers Pete
What @JEFF JOHNSON said ..if they're not pliable enough they won't seal with the little spring that's in there... p.s. From what you said about the fingernail test they sound like they are too old or made wrong? Try a 'Dunk' test ?
An old post, but a useful one… I have just crossed the road from CCS after scratching my head for a while over a leaky x246 NRV. I was assuming it was the seal, but it turns out it was the edges. I had a go at [soft] soldering the edges: But the problem is worse. Clearly there’s more to it… what am I missing? Might the bottom of the NRV have shifted slightly? -R
It looks ok in the photo but if you are sure it is the solder I would heat it up and remove the old solder, clean it up with wire wool and resolder it again using plenty of flux. Wash afterwards to remove the flux as it is corrosive.
Thanks @Fireexit1 - I’m assuming it’s the solder. Prior to my intervention there was just a steady trickle of bubbles when I dunked it. Now it pushes the pump handle up, or on occasion will hold pressure and them push the handle at the slightest disturbance. As a novice, are there any gotchas or techniques I’m missing? I fluxed, laid solder in the crevice and heated the outside of the tube with a little dremel versaflame. -R
Sounds like the rubber is not sealing properly maybe the spring is weak. Try swapping the spring with the one in the cock ?
No, it’s not the seal or spring. They worked okay before I soldered, and I’ve swapped them around several times whilst troubleshooting. A splash of water in the pump tube still suggests the leak is at the side rather than the central hole. There must be something amiss under my nice neat soldering. I’ll put cleaning it out and trying again on my todo list. In the meantime I have a spare. Thanks for your help, -R
They can develop a crack. All mine seem to be made of drawn tube, not rolled, so no seam to look for. Wire wool and a magnifying glass ?
Bingo! It didn’t take long to uncover this: Is it salvageable? If so, a job for soft solder or silver solder? -R
Well you have your answer at least.. Soft solder will do if you can get it into the crack. Again cleanliness and flux is your friend. Some would be tempted to drill a very small hole at the end of the crack to stop it moving along. It does not need to look pretty just fit in the font. Make sure it done not drop through and provide an obstacle for the pump leather. Good luck !
Indeed - a big step towards the solution! Am I right thinking that a high silver solder would be better at getting into the rack than soft solder? -R
To help get solder into the crack you can either use a fine cutting disc in a rotary tool (e.g. Dremel) to widen the crack a little but make sure you don't go right through the brass or, just trace the crack with a sharp pointed piece of steel.
I use a metal scriber to follow the the line of a crack like that before soldering, in you case, with soft solder. Cheers Tony
.. Lower down to the right, as you follow the swage line round, there may be another smaller crack? Best of luck with it.
You are right. Looking at the spot it seems to be (has been) a production problem. repairing is a challenge because in that spot is also the bottom part which is also soldered. So when heating this end up will also loosen that bottom part.
Yes, I have a spare, and will be getting another to replace it. This is an opportunity to work on my soldering skills. -R
It’s not going to win any prizes, but here’s this morning’s work: I found that covering the end of the tube with my thumb and pumping a stroke or two whilst the end is submerged in a bucket of water was a good way to check progress. The second crack that @podbros spotted was indeed also leaking. That test now shows no leaks, but a proper dunk test of the pressurised tank shows a very slow bubbling. I will admit defeat and learn my lessons - starting with properly diagnosing the problem before firing up the blowtorch! Thank you one and all for your help! -R
