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Thread: Removing locknut to replace MB 144 cork piston seal

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    Senior Member guyy's Avatar
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    Default Removing locknut to replace MB 144 cork piston seal

    I've been trying to replace the cork piston seal on a c. 1950 MB 144. I'm running into a little difficulty with removing the locknut. Oldfield just says "remove the locknut." Well, sure, but how does one keep the rest of the front piston stage mechanism from turning along with it? Holding the back end of the piston mechanism doesn't help.

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    Senior Member christof's Avatar
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    Default Re: Removing locknut to replace MB 144 cork piston seal

    have you tried to remove the whole mechanic from the back? normally,when the piston seal is shot this should be possible.

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    Default Re: Removing locknut to replace MB 144 cork piston seal

    Thanks for the reply, Christoph.

    Iíve been working from the front without removing the piston mechanism because thatís the procedure in the books.

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    Default Re: Removing locknut to replace MB 144 cork piston seal

    I've always removed the piston mechanism, telescoping shaft and all, for easiest access to the cork. It requires due care. I will have to look at Oldfield's description to understand his approach.

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    Senior Member christof's Avatar
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    Default Re: Removing locknut to replace MB 144 cork piston seal

    I think that the main problem is, that the hardrubber unit (nut and screw) which takes the cork seal is free turning mounted on the telescopic mechanism. If the old seal has shrunk, it turns freely in the barrel.

    MB_144_piston by c_m_z, auf Flickr

    As already said, in most cases that I had, the mechanism and the old seal could have been removed from the back of the barrel. If this doesn't work, and the seal get stuck in the barrels end, you still can unscrew the nut with a tubular wrench. (I don't know the correct term but I mean something like this

    Lamy 27 Kolben Werkzeug by C.M.Z, auf Flickr

    You just have to mount the new seal from the front of the barrel to prevent it from being damaged during installation. this is how I did it in each case.

    If you don't want to remove the whole mechanism, try to fix the old seal with a tooth pick or something similar, but be careful to the inner threads of the barrel.
    Last edited by christof; September 2nd, 2021 at 01:00 AM.

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    Default Re: Removing locknut to replace MB 144 cork piston seal

    Quote Originally Posted by christof View Post
    I think that the main problem is, that the hardrubber unit (nut and screw) which takes the cork seal is free turning mounted on the telescopic mechanism. If the old seal has shrunk, it turns freely in the barrel.

    MB_144_piston by c_m_z, auf Flickr

    As already said, in most cases that I had, the mechanism and the old seal could have been removed from the back of the barrel. If this doesn't work, and the seal get stuck in the barrels end, you still can unscrew the nut with a tubular wrench. (I don't know the correct term but I mean something like this

    Lamy 27 Kolben Werkzeug by C.M.Z, auf Flickr

    You just have to mount the new seal from the front of the barrel to prevent it from being damaged during installation. this is how I did it in each case.

    If you don't want to remove the whole mechanism, try to fix the old seal with a tooth pick or something similar, but be careful to the inner threads of the barrel.
    The toothpick did the trick. On to cutting the cork. Thanks!

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    Senior Member christof's Avatar
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    Default Re: Removing locknut to replace MB 144 cork piston seal

    great!
    good luck.

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