Coleman No. 2 - Pump Assembly and Check Valve

Discussion in 'Fettling Forum' started by idahostoveguy, Jun 2, 2012.

  1. idahostoveguy

    idahostoveguy R.I.P.

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    In my quest to fettle this Coleman Stove No. 2 fuel tank and pump, I found a leak around the pump tube and the check valve. I also ran into some other trouble with the tank, which I'm saving for another post in this epic series of fettles on the No. 2.

    I found it necessary to pull the cap on the end of the fuel tank that contains the pump and the check valve. I was also curious as to how the pump assembly worked with the check valve. I knew there was a tube that ran from the pump, but where it went, I didn't know until now.


    Here's the pump on the end of the tank off one of my No. 2s. I have already removed it before the photo session and slipped it back on for context. This is the early version of the pump, check valve and tank assembly. The pump tube is off-center with the check valve just above it.

    1338614418-xColemanNo2PumpAssembly_001.jpg


    In this next photo, it shows the end cap removed with the pump assembly attached. You can tell that the tank is in pretty rough shape. We'll save the reassembly for another post since it is going to be very radical maneuver in order to restore it. Suffice it to say, that it would not be in my best interest to reassemble things in their present state and hope the tank will hold the pressure and keep me safe.

    1338614424-xColemanNo2PumpAssembly_002.jpg


    Here's the assembly completely removed. You can see the tube running from the end of the main tube into the check valve. I had thought that it was strictly an air release valve, but as a matter of fact, it is definitely a check valve. We'll take a closer look.

    1338614432-xColemanNo2PumpAssembly_003.jpg


    Here's another angle of the pump assembly. I believe that all of the pump parts are made of brass since there is nothing corroding except for the surrounding metal that everything is attached to.


    1338614436-xColemanNo2PumpAssembly_004.jpg


    The smaller tube is soldered on to the end of the main tube where all the pumped content follows the length of this tube and into the check valve, which redirects air into the tank when the check valve screw is open a turn or two.

    1338614440-xColemanNo2PumpAssembly_005.jpg


    And here is the check valve. You can see the check valve ball in the center of the valve, which is shaped very similarly to other early stoves check valves. This part is eventually moved to the end of the pump and is removable in more modern versions. I think one of the problems with this design is that the check valve can not be replaced by merely removing with a tool. It would have to be desoldered from the tank. (In most cases you wouldn't want to remove the check valve anyway, but you guys can argue that point somewhere else. ;) :lol: ) In this case, curiosity removed the end cap and now we are able to see what exactly is inside the mysterious tank of the early No. 1s and 2s.

    1338614445-xColemanNo2PumpAssembly_006.jpg


    Here's the check valve on the inside and outside with valve screw installed. In modern versions, the valve screw is a valve shaft that resides inside the pump shaft and is opened using the pump handle. The same is true of this valve screw. It must be opened a turn or two to pump air into the tank. Modern pump shafts are also hollow and are made to force air to pass through when pumping. This old stove's pump shaft is solid so air must enter the pump through the pump cup assembly, which has a spacer ring to perform that duty, much like some of the Primus designed pumps.

    So, when pressure builds in the tank, the check ball closes the valve and no air escapes. The positive locking of the valve is done with the check valve screw, which does not allow any air to escape or go in, making this stove's pump assembly as nearly safe as its modern counterpart.

    1338614450-xColemanNo2PumpAssembly_007.jpg


    Here's the check valve screw. It has a similar shape to its modern versions, only this one is not inside the pump itself. In some ways, this may be easier to keep clean, but I guess in others it may cause manufacturing headaches since the check valve is soldered onto the end cap. The tubing from pump to tank still exists, it just empties out into the upper part of the tank into the air pocket at the top, which is another safety design so that fuel doesn't blow back through the pump if the check ball seal fails.


    1338614454-xColemanNo2PumpAssembly_008.jpg


    Here are the pump parts completely disassembled. We have the handle at the end of the shaft on the left. Next is the pump cap, which holds everything in. The spring keeps the pump from hitting the pump cap on the upward stroke. The pump leather retainer is next, then the spacer ring to allow air in on the upward stroke and then the pump nut that holds the pump leather but doesn't clamp down onto the leather since the space ring is thicker than the leather.

    1338614459-xColemanNo2PumpAssembly_009.jpg


    The following is the end of the pump tube, which has a threaded ring on the outside and inside to hold the pump in place. There's a bit of solder to seal the ring and tube in place.


    1338614462-xColemanNo2PumpAssembly_010.jpg


    Well, that's it for now. Hopefully, I can pull all of these posts together for a complete stove fettle.


    sam
     
    Last edited by a moderator: Jun 26, 2015
  2. hikerduane

    hikerduane Subscriber

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    Thank you Sam.
    Duane
     
  3. Rick b

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    Thanks Sam, quite a post. Fun to see these stove taken apart (and of course put back together).
     
  4. idahostoveguy

    idahostoveguy R.I.P.

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    Hi Rick,

    Am I supposed to put these back together? :shock: :lol: ;)


    I guess I better get on with this!

    Yeah, very interesting designs. I can see why the changes were made in the newer models.

    I am very surprised at the use of solder to hold the end caps on - very little. If you look at the second photo above, there is literally no solder on the end of the tank tube - just rust, and THEN the solder. There is no solder past the edge that can be seen. Basically, it's just sweat soldered into the seam with as little solder as possible.

    On my last tank fix, I tinned up the end and inside the cap just to give the solder and seam some beef.

    sam
     
  5. flivver United States

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    Hi Sam, Awesome photo essay well done. Your #2 is a rare stove, the earliest #2s used left over #1 tanks which is what you have there. There is little reason to take the end cap off one of these as any pump or check valve problem can be solved without disassembly. I have had a number of these tanks apart in the past but only for fixing dents or large rust holes. The only tricky part is getting a proper tin of solder on both parts before sweating insuring a good seal an a tidy job that looks as though it has never been tampered with. Mike...
     
  6. Doc Mark

    Doc Mark SotM Winner Subscriber

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    Hey, Sam,

    WOW!! This is a superlative post, and very timely, too!! VERY well done, my Friend!!!! Huge thanks for your excellent post, and for sharing it here!! Take care, and God Bless!

    Every Good Wish,
    Mark
     
  7. hillcountry

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    Thanks for the pump photos, I recently restored a Model 9 and was curious as to what the pump inside looked like. It doesn't have the screw but I imagine the pumps are similar.
     
  8. idahostoveguy

    idahostoveguy R.I.P.

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    Welcome hillcountry! It would be nice to see your newly restored Model 9. Put a picture up or two.


    sam
     
  9. exeter_yak

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    Hi Sam,
    I am quite interested in your fettle on this one as I will likely be doing the same sometime on the model 1 once I have one to mess about with. I hope the work on your stove is going ok.

    Best,
    Doug