C340A lower door snubber

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  • #84594

    Does anyone know where to find a replacement lower door snubber for a C340A? Used is fine.

    #101775

    They are hard to find. Cessna sells one which I bought new for about $700 some years ago. It was flimsy and didn`t last very long. There is a previous thread in this section on mine and other`s experiences. If you have an Aero industries unit it can be rebuilt . The cylinder has a left hand screw thread. and the brass cylinder is best held with a leather strap wrench to avoid deforming it. O- ring replacement and refilling the fluid is pretty straightforward. The previous thread has other options as well.

    #101776

    The previous thread is in the Sept. 2010 section.

    #101925
    rwelsh
    Participant

      My lower door snubbers in the 340 have been out of action for awhile so I thought I would give it a try and see how they work. Both ends unscrew. On the lower end there is a long rod attached with a long spring. The spring is attached with a 1/14 X 28 nut and under the nut is what appears to be a piston which is a small piece of machined aluminum that should fit snuggly in the cylinder and hold the other end of the spring. The outer cylinder has a thin inner cylinder with 4 thin slits about 5″ long. The slits allow oil to pass between the piston and the inner cylinder in a controlled manner to let the door down slowly.

      The inner diameter of the inner cylinder was 0.570 and the piston was had worn to 0.528, so the 0.042 was too sloppy allowing the oil to pass freely and not let the door down slowly. So I machined a new piston out of 6061T4 aluminum and made its OD 0.568. Now the door comes down slowly, but I have 80W oil in the cylinder so I am going to change to 50W and see how fast the door descends. It was a very easy machining job as 6061T is easy to work with. It is called an “owner produced part” and is legal under FAR Part 43 even if you have someone else machine it for you and you install it.

      Aircraft Spruce sells 0.625 6061T4 aluminum rod, and all you need is a piece 3/8″ long so buy one foot and have leftovers.

      I also did away with the swaged ends on the snubber cables as they tend to break easily. I replaced with 1/8″ stainless steel cable and used cable eyes for the ends and swaged with nicopresses. It is a good idea to wrap the cable ends at the swages with tape to keep the cable ends from catching on something. The cable and door snubber are covered with an upholstery sleeve the same color as the carpet.

      #101930

      Dick,

      Yours is different than mine – no springs, or they were gone when I got into it.

      I filed it up with aviation hydraulic fluid and it has been good ever since.

      Now I know what you use the lathe in your hanger for.

      Jim

      #143554

      Mine looks like the picture above. But how do they come apart? I read it’s opp threads and we used a strap wrench and got it loose but now it just spins. And ideas how to disassemble?

      #143706

      Bump. Any ideas for disassembly

      #143880

      Really? There is no one on this site that has the answer. I would hope we might be more of a resource as an owners group. Which brings to mind that most of the time I see, or ask questions, they never get answered. There are only about a handful of folks that used to respond to questions and I am sure they are getting tired of answering. Has twincessna outlived it’s usefulness is the bigger question?

      #143881
      ddivinia1
      Participant
        quote RHill2:

        Really? There is no one on this site that has the answer. I would hope we might be more of a resource as an owners group. Which brings to mind that most of the time I see, or ask questions, they never get answered. There are only about a handful of folks that used to respond to questions and I am sure they are getting tired of answering. Has twincessna outlived it’s usefulness is the bigger question?

        I have a 310 so I have no clue.

        I bet Tony has an answer

        D.

        #143896

        Darin, thanks for the reply.

        #143904
        rtowe
        Participant
          quote RHill2:

          Really? There is no one on this site that has the answer. I would hope we might be more of a resource as an owners group. Which brings to mind that most of the time I see, or ask questions, they never get answered. There are only about a handful of folks that used to respond to questions and I am sure they are getting tired of answering. Has twincessna outlived it’s usefulness is the bigger question?

          Rocky, I think if you posted a new post with something like “421B Air Stair Door Snubber Rebuild?” you might find someone browsing along but, keep in mind, the 421 series are the least worked on airplane by owners according to Bob’s surveys. I’m sure it might be the same snubber on different 400 series airplanes but, again, you gotta find someone that has been there, done that…Most people/mechanics out there probably just replace the snubber and move on, especially if there is no data showing the breakdown or part numbers in the corresponding maintenance and parts manuals, just my opinion…Like the other member stated, you could also try emailing Tony(Tony@TAS-Aviation) directly and he will probably answer in a few days being that his schedule is pretty demanding…

          #143908

          Robert, I imagine you are correct. Thank you.

          #144073
          rtowe
          Participant
            quote RHill2:

            Robert, I imagine you are correct. Thank you.

            I was going through service bulletins on our 421C and I ran across this bulletin. I don’t know if you have the same snubber but, here is the bulletin…

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