Hello everybody, This is my first post and I have a real problem here - while working on my Optimus 45 I deformed the head of the NRV beyond recovery. So the question is what do I do next? I obviously need a new NRV, but how do I get the old one out first? Also, how do I get rid of the old lead washer that seals it? I am thinking of enlarging the hole in it - and then using a screw extractor for highly effective, but destructive removal of the damn thing. Btw, I have worked on a lot of Coleman appliances and some Tilley lamps before, as well as a Petromax style lantern, so I do have a general idea of how things work. Thanks in advance!
Hi Manul, sometimes NRVs can be a real pain to remove! Soaking in all kinds of anti-seize oils and similar does not help much most of the time. A left-threaded drill (yes, these do exist!) can be the answer, also your own suggestion of using a screw extractor. Be careful, when entering too deep in the NRV it can make things worse by "opening up" the NRV. If all fails, you can still de-solder the pump tube (there is a tutorial somewhere on this site). New NRVs are for sale (made in India), have a look at The Fettle Box (members get a discount) or ebay. Hope this helps. Best regards, and welcome on board! Wim
https://classiccampstoves.com/threads/pump-tube-soldering.4071/#post-30605 https://classiccampstoves.com/threads/pump-tube-nrv-assembly.14028/#post-138233 https://classiccampstoves.com/threads/pump-tube-removal-and-nrv-rework.6371/ Best Regards, Kerophile.
I think @kerophile said it all in the above post. Next time be aware that that can happen and prepare accordingly. Ken in NC (Yes, I have followed the above instructions for a successful repair. And now I am much more cautious.)
I had a stubborn, rounded NRV on a Handi stove, I had almost gave up . I sat the tool over nrv and rapped it solidly several times with a small hammer. Popped loose with little force.
I already desoldered the pump and got the valve out in pieces. There was no lead washer, no wonder it was so stuck!
I've also had a couple of stubborn NRVs recently. The one on my Radius No.1. Required removal of the pump tube. I had tried a long series drill to enlarge the hole enough to allow a small scene extractor to fit but I couldn't get enough bite in the brass. In the end I figured it was safer to pull the tube out and finish the job on the bench without doing more damage. Even with the tube out that little piece of brass would not budge. Having drilled first there was not much of the NRV left to get a locking plier onto. I used another drill to enlarge the hole further whilst still keeping it under the size of the NRV thread. I then used a chainsaw file to open it up a much as possible before the screw extractor could do its job. The other one was on a Primus 631 torch. I thought being able to unscrew the tube would make things easy. Wrong! No amount of soaking or secure clamping of tools seemed to help. I used the same technique of drilling and filing to enlarge the hole however I able to get a long screwdriver to bite and undo the stub that was left. By using the small chainsaw file I was able to make the hole slightly eccentric which allowed the tools to grip. The next time I have this problem I'm going to try touching a heated rod onto the top of the NRV as I saw was suggested by someone on CCS in another thread. This may help release the stuck thread without needing to get more medieval with it. Once the head on the NRV is rounded off there aren't too many options. I applied some antisieze compound to the new NRV before refitting so that in 50 years time some future stove might have better luck!
The problem with the NRV comes from the standard NRV-keys. The key should be kept exact centric to the pump-tube on both ends, the upper and the lower end. This can be done with some pieces of plastic hose of suitable diameter. Slit the side open to fix it on the stem of the key. If the key is centric, it will not slip off and ruin the sides of the NRV. Another possibility is to buy one of these very perfect Japanese keys, if you can afford it. Regards Radler
Here's what was left of two NRVs that I forcibly removed. After drilling and filing; in the first picture a screw driver tapped into the drilled centre hole was then used, and in the second a proper screw extractor completed the job.
I have had success in removing stubborn Primus NRvs by first putting a little penetrating oil into the pump tube and then heating a cheap NRV tool or other iron rod to red hot and repeatedly applying it to the head of the stuck NRV. Then, using a well-fitting tool, tighten the NRV fractionally one or two degrees to break the bind and unscrew. Tapping the NRV with a drift pin can also assist in breaking the bind. With the benefit of hindsight, I think the important thing is to use this or a similar method before rounding the head.
@phaedrus42 Sounds like great advice! I will follow those steps next time I have this problem. Removing pump tubes and drilling out stuck valve bodies should be the last resort!
Hi, I'm glad that you managed to get the stuck NRVs out. A couple of points that you mentioned: 1. It is really important to have a good quality NRV removal tool, preferably with a self-centring ability. Stu has made excellent tools: https://classiccampstoves.com/threads/georges-new-nrv-tools.17401/#post-177411 https://classiccampstoves.com/threads/nrv-repair.17628/#post-179914 2. If you have to remove a pump tube to expose a really seized NRV, chances are that the head of the NRV will already be severely mangled due to earlier removal attempts. https://classiccampstoves.com/threads/pump-tube-nrv-assembly.14028/#post-138233 The best way to remove the remains is to first un-solder the base of the pump tube to expose the stuck head of the NRV. Now heat the base piece in a torch, and then immediately quench into cold water. Repeat twice more. Grip the base section carefully (as you want to re-use it) in a pair of circular head pliers and remove the head of the NRV using vice grips, or other suitable tool. Removal should be easy as the heat-and-quench treatment will have done its magic Check that your new NRV fits the base piece, before un-screwing it again and soldering the base piece onto your pump tube. Best Regards, Kerophile.
Manual Before I try to undo an NRV I put penetrating oil into the pump tube ( a fair bit) then replace the pump rod and apply pressure this can aid in the penetrating effect oil if that does not work I fill the tank with boiling water to heat the NRV and try again. If that does not work I walk away for some time and leave the oil to do its job! It does not always work especially if the head of the NRV is already slightly damaged. I have in the end had to unsolder a fair few tubes and tackle it from the other end as @kerophile suggests which in your case may well be the only answer I am afraid! Good luck Nick
I wonder if the diameter of the NRV head base is pretty consistent be good to make a tool that tightens around this (a bit like a tightening collet) and enables removal whilst having a mashed head
It was recently brought to my attention that one of the reasons for slow response from penetrating oil in a stuck NRV is that there is quite an efficient seal, lead or HDPE, between the NRV and the pump tube. If one could find a way to apply penetrating oil to the inside of the pump tube, it would be much more efficient. Ref: @exeter_yak I have a Campingo 1 I have to remove the pump tube to fix a previously 'mangled' NRV. This is not my first rodeo, but, a PITA nonetheless. I prefer any other method, so far, to that.
I second this. I just removed a partly rounded NRV from a Primus 527 with a few cautious taps on the end of the removal tool. An old mechanic taught me the trick for a stuck spark plug.
Heating the NRV like the big tool Stu made, is it will soften the solder and the end of the pump tube will drop out. Just some caution. Duane
A good nrv tool on an impact wrench with minimum torque is maybee a solution. I m going to solder a 3/8 socket on a custom made, closed, nrv tool. Last time I encountered the stuck nrv problem it ended with desoldering, turning a new base of the tube and tapping it... Before resoldering the whole assembly.
