HASAG 00 NRV problem

Discussion in 'Stove Forum' started by A A C, Apr 12, 2021.

  1. A A C

    A A C Norway Subscriber

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    I am trying to overhaul a HASAG 00 . The NRV is not functioning well (the non-return bit is returning) . I have tried to revive it with some warm oil and gentle massage but no luck . I want to take the valve out to replace the spring and pip but despite having a proper key for NRVs it wont budge . The tool seems to have poor purchase on the valve end , not «deep» or tight. Are HASAG NRVs differently dimensioned than other stoves ? Are they reverse threaded ? I dont want to chew up the valve end more than I have . Any tips would be greatly appreciated
     
  2. hikerduane

    hikerduane Subscriber

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    May have to unsolder the pump tube. Other ideas may be forthcoming.
    Duane
     
  3. A A C

    A A C Norway Subscriber

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    Yes . I wpould really like to avoid that . The unsoldering might be okay but with my present skill level the resoldering could be a real challenge .
     
  4. gieorgijewski

    gieorgijewski Subscriber

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    use plastic - like clay - child use - mass. You get "reverse" of neded tool...
    like key copy process.
     
  5. Dean

    Dean United Kingdom Subscriber

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    There can be a technique to the way you apply pressure to the end of the tool while turning it. Some say hold the tool in a vice and apply pressure to the stove while turning the stove. Others say the readily available tools can be a bit useless and something that is a closer fit to the pump tube is a better design as there is less scope for it to "walk" off the NRV head. An appropriately sized steel rod with a slot cut in the end to the right width and a tommy bar handle or hex head at the other end might do it.
    I had one stove like that - it simply would not budge. I persevered, applying some downward pressure to tool and stove tank and it did come undone OK. You might want to tighten it a shade first, to crack any corrosive seal.
    There are some designs of homemade tools here on the forum. I think @hikerduane came up with something, and probably @two berth as well as others. Try searching "NRV tool"
    Best of luck
    Dean
     
  6. A A C

    A A C Norway Subscriber

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    Thanks Dean ,
    Ill follow your advise. I think i will make the key fit the pump housing exactly by rolling some insulating tape round the shaft . I am going to try «shimming» the business end of the tool with thin brass or even aluminium . Will certainly try the tightening first tip . Lots to try here . Thanks again - Alastair
     
  7. hikerduane

    hikerduane Subscriber

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    I have added some tape to make the tool a snug fit in the pump tube. Took years to finally get someone to make a tool that locks onto the pump tube to prevent rising off of the NRV head. A couple old, old Primus 96 stoves still were hard with the tool. Mostly Primus 96 stoves are the hardest to remove the NRV from.
    Duane
     
  8. A A C

    A A C Norway Subscriber

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    Thanks Duane ,
    I will take your advise . I think I’ll take a step back from this problem and regroup . I am getting a bit frustrated and brute force and brass components are never a happy combination . Will look at the stove again in a week or so . The old valve works but it pushes the piston out due to back pressure . The stove is otherwise complete and in good condition , I’d hate to make things worse. Got an Emperor in the post so I won’t get bored :content:.
    Thanks for the advise . Cheers Alastair
     
  9. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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  10. A A C

    A A C Norway Subscriber

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    Thank you I’ve read the linked posts with great interest . First class instructions . I must admit that I am not skilled at soldering . I think I will put this project on the back burner . I’ll practise the techniques you describe and maybe do a couple of simpler repairs before I attempt the pump removal . Maybe I’ll try it on a donor stove or on a stove thats in very poor condition as a trial . Thank you for sharing your knowledge . This is a fabulous community , everyone so helpful and encouraging
    Regards Alastair
     
  11. hikerduane

    hikerduane Subscriber

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    I damaged one fount by wedging it in a vise with a NRV tool on the NRV, caved the area by the pump tube some, so luckily no further damage.
    Duane
     
  12. A A C

    A A C Norway Subscriber

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    @hikerduane . Sounds like the kind of thing I do regularly. I am trying to correct my inherent clumsiness . I am the type of bloke who strips two of every five screws. My father was a great practical mechanic , he’d despair of my efforts «you couldn’t put a nut in a monkey’s mouth» being one of his assements of my work .
    Thanks for your help and advise . Imappreciate it
     
  13. theyellowdog

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    I had to remove the pump tube on my hasag 00. It is not a difficult job, but it feels daunting the first time. After you have done it once there will be no stopping you.
     
  14. A A C

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  15. snwcmpr

    snwcmpr SotM Winner Subscriber

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    Patience is the most important tool in the toolbox for this task.
    Penetrating oil, I prefer Kano Kroil or 50/50 ATF/Acetone. ATF = Automatic Transmission Fluid.
    Add, let set for days or weeks. Try again.
    Add, let set for days or weeks. Try again.
    Repeat as necessary.

    These NRVs have been there a long time.

    Ken
     
  16. A A C

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    Thanks Ken . I think Ill give this a go before I reach for the gas torch . I have looked for Kroil here before and I think I can source it online from Brownells the firearm accessory suppliers. Otherwise the ATF / Acetone solution is easy enough to get. Cheers Alastair
     
  17. hikerduane

    hikerduane Subscriber

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    I find the hardest part of removing the pump tube is holding it in correct orientation and depth when reinstalling. I have a tool by old member Stu that holds it, but a third hand would still be very handy.
    Patience and maybe some kero in the fount and tube might loosen the NRV with a little time. Others have tried shock. Heating the fount with boiling water I believe and then adding ice to the pump tube.
    Duane
     
  18. A A C

    A A C Norway Subscriber

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    Cheers Duane
    I think I’ll ask a buddy to help out if I have to take out the tube , someone else to put blame on could be handy . I’ve toyed with the idea of heating the valve via the tube with a soldering iron . I have one that should fit in the tube . It doesn’t have great effect so shouldn’t have the potential for collateral damage .
    Regards Alastair
     
  19. snwcmpr

    snwcmpr SotM Winner Subscriber

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    Heating up the NRV might melt the solder at the bottom of the tube. if so, the end of the tube will drop off, and you will have to remove the tube to replace it. Be careful.
     
  20. A A C

    A A C Norway Subscriber

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    Thanks Ken , great to be warned of pitfalls like this