Sticky old valve

  1. Richard T New Member

    Messages:
    14
    Location:
    Guildford, UK
    Working on restoring / fixing up an old compressor (vertical-style Broom Wade) and I'm looking at the drain valve, which is a simple but nicely-made little thing :
    20200728_201045.jpg

    Dismantling it, it's really simple - just a taper-fit centre being pulled down into a conical bore by the spring at the bottom :
    20200728_201936.jpg

    However... when I clean and reassemble it, it's incredibly tight, almost sticking solid. Greasing or oiling doesn't seem to help - almost makes it stick more. There is a second identical valve on the compressor I haven't touched yet, and that is smooth and good to use. So it's almost like it doesn't want to be too clean. I realised you could look at it a bit like a morse taper fit - the cleaner it is, the tighter it will be.

    Is there some secret type of lubricant I should be using, or some other trick to making this type of valve turn smoothly ?

    Thoughts appreciated !
    Richard
     
  2. hunter27

    hunter27 Pete

    Messages:
    633
    Location:
    Lancashire UK
    On tapered seat domestic gas valves eg old cookers fires and gas meter inlet valves we used Rocol graphite grease.
     
    sg66, brightspark and ronan like this.
  3. Other Daniel

    Other Daniel Member

    Messages:
    92
    Location:
    France, Charente
    An interesting question, upon which I will dwell and ponder.
    No doubt someone else will have the answer immediately :laughing:
    Inspect the two surfaces V carefully again. :fish: *

    ATB,
    Daniel
    * Goldfish to indicate pondering mode, as I wanted to use it, and I still don't know it's true meaning.
     
    Parm and Morrisman like this.
  4. Morrisman

    Morrisman Forum Supporter

    Messages:
    2,720
    Location:
    Staffordshire, England
    You may find it is not round, but worn oval, maybe from over tightening the main body at some stage, thus locks up when turned.
     
    slim_boy_fat and mtt.tr like this.
  5. rtcosic

    rtcosic Member

    My offspring use that to point out any of my forgetful moments. 'Dad's in goldfish mode again'. The goldfish has a very short memory so each time it circles its bowl the view is a surprise.

    Not to be confused with the Goldfish Club

    I used Autosol chrome polish to 'lap' those and a smear of the grease that came with a CV rebuild kit. They were drain valves on various engine cooling systems.
     
    Other Daniel likes this.
  6. Other Daniel

    Other Daniel Member

    Messages:
    92
    Location:
    France, Charente

    You may have something there @rtcosic ,perhaps putting any honing compound, or aggressive polish
    on the taper and it's seat, re-assembling, then turning around quite a few times. Dismantle, clean and
    lubricate, then reassemble ? :dontknow:
    Might work.

    Morrisman, unlikely it has been overtightened, as it's assembled with a spring, washer and split pin.
    The compressive effect of the assembly is predetermined.
    But, it may well be oval. Only, Richard implies it was fine before he touched it :laughing:

    ATB,
    Daniel
     
  7. gordon stephenson

    gordon stephenson Forum Supporter

    Messages:
    7,019
    Location:
    Skelton in Cleveland U.K.
    Brasso used to be the go to lapping material for that type of tapered plug valve, Just use light downward pressure while do in the lapping.
     
    brightspark and 8ob like this.
  8. rtcosic

    rtcosic Member

    I found I needed the slightly more abrasive/aggressive Autosol. I had tried the Brasso first. Brasso seems to clean brass by chemical action as much as physical. Maybe the clue is in the name!

    Edit: I wonder if valve lapping paste might be best of all if the mating faces are in poor condition. I haven't seen my little double-ended tin and sucker-on-a-stick (named sucker 50% extra) for years.
     
  9. Seadog

    Seadog Forum Supporter

    Messages:
    6,976
    Location:
    NE London - UK
    It's a standard Enots 1/8" BSP petrol tap by the looks of it. The same as fitted to the Gold Star and a host of other BSAs.
     
  10. brightspark

    brightspark Member

    Messages:
    31,750
    Location:
    yarm stockton on tees
    clean the face with a bit of 1200 wet and dry and bed it in with either rubbing compound or t cut . clean and put a bit of vasline on it
     
  11. waddycall

    waddycall Member

    Messages:
    1,229
    United Kingdom
    Ive used fine valve grinding paste on similar and then molykote or waterproof grease dependant on what it was.
     
    brightspark likes this.
  12. gordon stephenson

    gordon stephenson Forum Supporter

    Messages:
    7,019
    Location:
    Skelton in Cleveland U.K.
    The danger of using Grinding paste or the hard particle product, is that minute pieces of the grit can become embedded into the softer brass and cause wear problems, this happens to larger white metal bearings if hard particles become embedded they then cause damage to the journal,
     
    Last edited: Jul 30, 2020
  13. brightspark

    brightspark Member

    Messages:
    31,750
    Location:
    yarm stockton on tees
    pretty similar to making a lap out of aluminium .the paste beds in the aluminium and wears the steel down that u are lapping
     
  14. the artfull-codger Member

    Messages:
    436
    Location:
    north yorkshire england
    I use "timesaver" lapping compound, there's 2 different grades [& various grit sizes] for hard or soft metals, it's guaranteed not to embed into the metal it's lapping.
     
  15. sg66 Member

    Messages:
    647
    Location:
    northeast
    Yup, re greased many wade iso valves, they are nice little things to strip and re grease.
     
  16. Richard T New Member

    Messages:
    14
    Location:
    Guildford, UK
    Thanks all - sounds like lapping it gently and then some "grease with good stuff in it" is the best approach. I've got some Autosol, will try that.
    I did clean the inner component, gently, on a deburring wheel, but lapping would be more certain of actually getting a fit.
     
    Other Daniel likes this.
  17. Richard T New Member

    Messages:
    14
    Location:
    Guildford, UK
    ...and just to follow up, I used some autosol to lap it properly and then some graphite grease, its working perfectly now. I probably cleaned it too zealously in the first place.

    thanks all for the help !
     
    sg66 and 8ob like this.
Advertisements