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Thread: HELP - HW50s dieseling

  1. #1
    Sharp Shooter

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    Default HELP - HW50s dieseling

    Hi Folks,

    2 days ago i noticed that when cocking my HW50s, that at a certain point there is a noticeable metal scrape during the action.

    I took the stock off to have a look but you cant see much more than just the leaver moving up and down a slot. - it was clear that it wasn't the piston itself as the scrape was still present even with the spring cocked back while moving the action.

    I walked over to the garage to look for any oily substance to help lube the gun a bit. - I found 2 stroke oil i use in my KTM 300... I put a few drops in the slide and closed the gun up again

    After a few pellets I could feel the scraping subside slightly and thought it would eventually just work its way out with the lube having definitely helped. - I did notice a slight amount of smoke after each pellet but this did not worry me as I knew it was probably residual oil and the gun still sounded exactly the same.

    Today i got a urge and placed my target out, loaded the HW50s and BOOM!! - Guys it sounds like a firearm! I took one more shot to confirm and BOOM!! YES definitely this thing is Klapping like a 22 rim-fire with significantly more smoke than 2 days ago. - My ears were hurting it was so loud


    So my questions:

    1. I thought the piston was sealed and it drew its air thought the front when you cock the gun? - how did the oil get in there?

    2. How do I fix this? - I will not shoot the poor weihrauch like this.

    3. In future, if ever I want to lube anything on this rifle, what should I use instead? - 2 stroke oil is obviously not advised


    Sorry for the long post.

    Thanks Guys and Happy new Year!
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  2. #2
    Marksman
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    Contact Jaco wp without delay
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  3. #3
    Marksman

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    Sounds like an excessive amount of oil got in front of the piston seal and into the compression chamber. Grease is always better for lubricating a spring air rifle, and even then it's normal for minute amounts of grease to get past the piston seal, on the cocking stroke because the piston seal only really seals best when the piston is moving forward on the firing stroke. Your best fix is to open the rifle up, dry the oil with a cloth then put the rifle back together using a light coat of automotive CV joint grease on the spring and piston. Make sure you don't get any grease on the front of the piston seal, applying a light coating of grease on the side of the piston seal is fine. You can find videos of how to take the rifle apart safetly on YouTube .
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  4. #4
    Sharp Shooter
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    The scraping noise is the cocking lever galling against the bottom of the compression tube.
    Unfortunately an ailment many HW50's suffer from. Was apparently addressed by the factory on newer models with an delrin insert in the arm.
    If your rifle has the insert, just make sure it stays well lubricated.

    If not, I would suggest you send it to someone that can put one in. JacoWP has done one of mine, he also does an awesome tune on them
    Last edited by Pellet pusher; 31-12-18 at 21:05.
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  5. #5
    Sharp Shooter

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    Thanks for the advice guys.

    The rifle is currently stripped and cleaned - i found some awesome YouTube clips to guide me like you guys suggested.

    I also saw where the galling is happening. yes my rifle does not have the insert under the arm.

    I made a cork slider witch I will place in the arm when I assemble that will hopefully stop the scraping from happening.

    I will let you guys know how it fairs when I assemble tonight. - today is my 1st day back at work........ hence being so active on the forum today
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  6. #6
    Sharp Shooter
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    Good luck with the cork insert. If it does not last try a piece of leather, it has far better wear resistance. Think of all the older rifles with leather piston seals.
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  7. #7
    Sharp Shooter
    WP HFT/Springer Champ '15

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    Rather use a piece of plastic /hdpe/delrin/acetal. Remove the roller that is fitted and fit the plastic piece in its place. Use the same pin from the roller
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  8. #8
    Sharp Shooter

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    Quote Originally Posted by Mr H View Post
    Rather use a piece of plastic /hdpe/delrin/acetal. Remove the roller that is fitted and fit the plastic piece in its place. Use the same pin from the roller

    That's exactly how I do.

    Here a large glider in a HS50S with the original roller and its pin taken out
    picload.org | 26_hw50s_2018-04_26_spannhebel.jpg

    And this smaller though perfectly working version I spent a HW30S where I additionally had to grind down the cocking arm.
    picload.org | hw30s_201602121_spannhebel-san.jpg
    picload.org | hw30s_201602121_spannhebel-san.jpg
    picload.org | hw30s_201602121_spannhebel-san.jpg
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  9. #9
    Sharp Shooter

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    Hi Guy's,

    Thanks a lot for your responses it is much appreciated

    So far the cork-mod(lol) has held up nicely and the scrapes are pretty much eliminated. - I will for sure look into a more permanent fix soon but thanks for the confidence you gave me to actually take the thing apart.

    I took a few shots today after servicing the rifle when i posted last. I also added a one piece mount to secure the shifting scope scope(it literally shifted the back mount off the rail by the time i noticed that the accuracy was going down) and received a fresh batch of JSB exact diabolo 4.53(thanks pelletpusher!). - the difference between these new jsb's and the tin i had left over from 7 years ago is drastic! They must have upped their QC cuz i have had some of those old pellets plain fall out the gun when loading that's how inconsistent the sizes were. These new ones feel the same when entering the barrel each time.

    Guy's I bought a real cheap Bushnell 3-9x40 knockoff(it must be fake cuz it was R550.00 at a Chinese shop) scope for this rifle not long ago. - It cant zoom past 4x then it looses all clarity on either the reticle or the target but its helped immensely.

    My best group today was a 5mm ctc at 15m. - had no idea this little break barrel(and me!) was capable of that - I guess MZE knew all along tho.

    With my 1st pcp arriving shortly i am super excited with this rekindled hobby!

    Thanks again guys
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