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Thread: removing shock cords from PA-12

  1. #1

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    removing shock cords from PA-12

    Yeah, I know, cut em. I am working on a PA-12 and have to remove the gear. Customer just installed new shock cords. Anybody know a way to get these off intact? Thanks for any thoughts, Larry

  2. #2
    Colorguns's Avatar
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    Turbobeaver might have an idea?

    Doug

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    PerryB's Avatar
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    However you go about it, you should tell the owner there is a new AD requiring all PA12's to be converted to 18 gear and they're grounded pending compliance.
    After Monday and Tuesday, even the calendar says WTF !
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  4. #4
    algonquin's Avatar
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    I did one a few years ago so this is a bit foggy. I slipped a strap from a ratchet tie down in and worked it under. Tied a knot put a pry bar through and used the arch to pry against . When I got it over I think I needed a screw driver to move it clear and let it down gentle. You'll have to work it a bit but it worked good luck.

  5. #5
    www.SkupTech.com mike mcs repair's Avatar
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    1. cost of new cord = 1X

    2. Labor to attempt to remove existing new ones = 3X

    3 if Step 2 don't go well, medical bills and loose of work time and/or life = 1243255X

    use knife...

  6. #6

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    Quote Originally Posted by mike mcs repair View Post
    1. cost of new cord = 1X

    2. Labor to attempt to remove existing new ones = 3X

    3 if Step 2 don't go well, medical bills and loose of work time and/or life = 1243255X

    use knife...
    Read Algonquin and thought about it. Sounds doable. Read Mike and decided his idea was prolly safer. Guess I cut em. Thanks to both, Larry
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  7. #7
    Charlie Longley's Avatar
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    Quote Originally Posted by Larry Huntley View Post
    Read Algonquin and thought about it. Sounds doable. Read Mike and decided his idea was prolly safer. Guess I cut em. Thanks to both, Larry
    Having done quite a few PA-12 shock cords. I prefer Mike's idea.

  8. #8
    R. JOHNSON's Avatar
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    I've installed them on a J-5 with an engine hoist and rope, don't think it'd be too difficult to go back off with them the same way.
    Ryan

  9. #9
    Charlie Longley's Avatar
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    Quote Originally Posted by R. JOHNSON View Post
    I've installed them on a J-5 with an engine hoist and rope, don't think it'd be too difficult to go back off with them the same way.
    Unlike a stock J-5 a stock PA-12 doesn’t have hydrosorbs. The shock cords are buried in the belly. It would be interesting getting an engine hoist in there. I use a modified handyman jack to install them.
    Last edited by Charlie Longley; 05-18-2018 at 08:23 AM.

  10. #10

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    There is a special tool, and even that doesn't work real well. I doubt I would even attempt a -12 without the tool.

    If cost is an issue, there are suppliers who sell out-of-date shocks for cheap. As far as I can tell, they are almost as good as fresh ones .

    - I have a 1955 Chevy bumper jack modified so J-3 struts can be undone without cutting and sort of safely redone in about 20 minutes per side max.

  11. #11
    Steve Pierce's Avatar
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    Quote Originally Posted by Charlie Longley View Post
    Unlike a stock J-5 a stock PA-12 doesn’t have hydrosorbs. The shock cords are buried in the belly. It would be interesting getting an engine hoist in there. I use a modified handyman jack to install them.
    I thought the J5 had shock cords like a PA12. I thought the Pacer/ Tri-Pacer and the later Super Cubs and Pawnees were the only ones using hydrosorbs.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  12. #12
    Charlie Longley's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    I thought the J5 had shock cords like a PA12. I thought the Pacer/ Tri-Pacer and the later Super Cubs and Pawnees were the only ones using hydrosorbs.
    I misspoke the J-5 has external shock struts and bungees similar to a J-3. The PA-12 has internal bungees and a rubber bumper.

  13. #13
    R. JOHNSON's Avatar
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    Quote Originally Posted by Charlie Longley View Post
    Unlike a stock J-5 a stock PA-12 doesn’t have hydrosorbs. The shock cords are buried in the belly. It would be interesting getting an engine hoist in there. I use a modified handyman jack to install them.
    Was a J-5C, same as a PA-12 shock arrangement I believe. Raise the tail and take the door off.
    Ryan

  14. #14
    Charlie Longley's Avatar
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    Quote Originally Posted by R. JOHNSON View Post
    Was a J-5C, same as a PA-12 shock arrangement I believe. Raise the tail and take the door off.
    I didn't realize that. All the J-5's I've seen had external shock struts and bungees.

  15. #15
    PA-12 okie's Avatar
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    What cords does he have on them, and how many? I've have had a dickens of a time determining what should be on mine. I had new ones installed at a pre-buy annual, and the tag on them states 06-00826, which I've been able to cross reference as a 31322-05 and 1280HD. I've seen conflicting information as to how many of these should be on the plane. Piper Service Memo 12 states 6 each 31322-05's, however Univair states there should be 4 each 1280HD's. I've read posts on here that 6 each of the 1280HD's would be like welding your gear, and my back side concurs. I have never seen my gear flex....ever....and I live on a bumpy grass strip. So I think I'm reading that the recommended method of removal is via knife, but I'm wondering about the recoil and what technique to use to be done safely?
    stock PA-12, 0-235 configuration

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    cubpilot2's Avatar
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    Quote Originally Posted by PA-12 okie View Post
    So I think I'm reading that the recommended method of removal is via knife, but I'm wondering about the recoil and what technique to use to be done safely?
    stock PA-12, 0-235 configuration
    I often use a hacksaw with fine tooth blade. Keeps you well back from the action....
    Ed
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  17. #17
    PA-12 okie's Avatar
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    That sounds like a reasonable technique. I'm hoping someone on here can help me determine the number I need. I currently have 6 of the 1280HD's and its stiff as a board. I'm beginning to suspect that I need only 4, and assume (I know) that I could cut one off each side without damaging the remaining ones? I'd sure like to see how nice it is to have suspension on my plane. I've heard after some use they soften up, but I've got 50hrs on these and no flex in suspension at all.
    If someone can verify that 4 is the correct quantity, please steer me to the references that I can provide to satisfy my IA!!

  18. #18

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    Changed my cords on my '47 -12 last year. I installed 3 1280's per side. Note that these are 1280's not 1280 HD's. Got them from Univair. Seems like they cost 35.00 or so a piece. The gear works just fine. Also I was faced with having to cut a set of cords off the left side after installing them due to the discovery of a crack on the gear assy. that required welding and recovering. I used a sharp utility knife/razor simply cut the cords on at a time. Go slowly and pay attention as they do let loose with a bit of force.
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  19. #19
    PA-12 okie's Avatar
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    Shattuck...Hey another Okie with a 12?! I'm at Guthrie. Thanks for the info...that's exactly what I needed to hear. Now....since I know mine are the 1280HD's....I'm thinking of cutting one off each side to see how they operate.

  20. #20

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    Don't forget to replace or at the very least inspect the rubber bumper pad on each side when you have the bungees off. you'll be glad you did so you don't have to fix a flattened cracked cross tube that the gear closes against. You can imagine why I know this:

    http://www.univair.com/piper/piper-p...-bumper-block/
    Staying alive in an airplane has a lot more to do with mastering ourselves than mastering the aircraft.

  21. #21

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    Way up here in N.W. Oklahoma. Been flying out of WWR for 12 years now. Always glad to hear about -12's in Oklahoma. Seems like there was a post about running (2) 1280HD cords per side and it believe it was a working combination. Like me know what you discover. Also agree with MT12 on the bumpers, definitely need to be changed when doing the cords.....

  22. #22
    39-J3's Avatar
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    Is there an STC to put 18 gear on a PA-12? I was looking at a 12 on floats a while back but was turned off when I heard all that they had to go through to remove the landing gear and install the floats.

    Larry.

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    Yes, atlee dodge has the stc for 18 gear on a 12, and not so coincidently I have a set of Edo 2000's for a 12 for sale. As it turns out theres just not that much water in Montana
    Staying alive in an airplane has a lot more to do with mastering ourselves than mastering the aircraft.
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  24. #24
    www.SkupTech.com mike mcs repair's Avatar
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    Quote Originally Posted by 39-J3 View Post
    Is there an STC to put 18 gear on a PA-12?..
    Larry.
    there are a few different STC's...

  25. #25
    Charlie Longley's Avatar
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    Quote Originally Posted by MT12 View Post
    Yes, atlee dodge has the stc for 18 gear on a 12, and not so coincidently I have a set of Edo 2000's for a 12 for sale. As it turns out theres just not that much water in Montana
    There’s water near Seattle. How much do you want for the 2000’s?

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    Freshly blasted with walnuts shells, leak tested and sealed, fresh float laquer, double rudders, all hardware, $9250, 406.431.8944. I'm on the road this weekend will post ad and pic's on Tuesday
    Staying alive in an airplane has a lot more to do with mastering ourselves than mastering the aircraft.

  27. #27
    PA-12 okie's Avatar
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    So just as a follow-up and for that next guy that needs to know. The cutting off of one per side was a non-event. I tied several loops of 1/4" nylon rope all the way around both sides, then took a utility knife and started at the outside edge of the outside cord. Just slowly and gently nicking it will cut the individual rubber bands easily. once you get about 3/4 of the way through it, it starts to release itself and since mine were tied when it released, it just sprung a inch or 2. Nothing violent, or damaging. It took a little finagling to thread it back out, but it wasn't difficult. I have yet to fly it and see how much difference it made, but it had to have helped. When I install new chords next time, I'll go with 3 per side of the 1280 non HD's.
    Now once I get my new tanks installed and new sealed struts on, I should be flying again!! Thanks to all of you for your input, helpful as always!

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