Results 1 to 4 of 4

Thread: Autococker Pneumatics leaks - How to diagnose and fix them.

  1. #1

    Autococker Pneumatics leaks - How to diagnose and fix them.

    Trying to set up a guide to help people. Please feel free to post additional information or to correct anything. If you have an issue yourself and have followed the steps outlined below, please post and others here can help resolve it for you.



    There are some very important steps to take to help diagnose pneumatic leaks. All of these should be completed and verified before moving on, otherwise you may do far more work than needed, or never fix the leak.

    1) Make sure you have air. Some micro gauges show you will still have a thousand PSI or so in the tank, but really you are out of air.
    2) The LPR (Low Pressure Regulator) is set high enough. You need a high enough LPR pressure to make sure the o-rings seat and seal up. Setting the LPR too low, especially on new pneumatics where the o-rings haven't seated yet can cause a leak which is fixed simply by increasing the LPR pressure. The LPR should be set strong enough to cock the hammer and pull the bolt back clear of the breach reliably.
    3) The gun is timed. Even if it leaks you should be able to set the hammer timing and the pneumatic timing so that it is at least close and allow the gun to cycle. The hammer should be able to cock and the bolt move correctly when the trigger is pulled. This means setting up the hoses correctly for the type of frame and type of three way. An illustration of this can be found at the following link http://dealer.inceptiondesigns.com/p438835140/e30fef52c and below (click the image twice for a high resolution version).





    4) Be certain of where the leak is. Many times a leaking barb or hose can jet air sideways making you think the leak is from somewhere it is not. I recommend using a small spray bottle filled with water. I use 50% water and 50% rubbing alchohol in mine as that is also helpful to clean the parts. Spray or drip water onto the pneumatic connections and the suspected leak areas to verify the exact locations from the bubbles.

    If a barb is leaking where it connects via it's thread remove the hose, remove the barb and re-install with a good thread sealer, I recommend Loctite 545. This must be allowed to dry for 24 hours before being pressurized. Blue Loctite is NOT a thread sealer. It may work but isn't the best compound to use. In a pinch you can try using it though.

    If a hose is leaking at a barb fitting you may be able to fix it by removing it, cutting it slightly shorter if you have enough slack and replacing it. If you do not have enough slack or it still leaks you may need new hose. Inception Designs has a kit with new hose and hose locks that help keep the hose in place and cleans up the look at the ends of the cut hoses.

    Different products from different manufacturers may leak from certain locations but the causes be different. Here we will concentrate on helping with Inception Designs products. Our advice may work with other manufacturers components but we don?t guarantee it and suggest you contact them if you have any specific issues or questions relating to their parts.

    With a full pneumatics set from Inception Designs, leaks from incorrect timing, internal o-rings or seals will tend to show at the three way. Not all leaks at the three way are caused by issues at the three way so it's important to follow the test procedures and verify what happens with the leaks in order to diagnose and fix them.

    First ensure the three way is close to being timed correctly. We make this super easy with the Inception and UFC three way. When using a Slide frame the adjuster end for the Allen key should be flush with the end of the three way body. When using a hinge frame the adjuster end should be recessed into the body by approx. 4-4.5 mm (0.15" to 0.18")

    Please refer to the image found below to check your hose paths and to get an idea of where the three way shaft should be with different frames. The dotted line shows where the middle three way o-ring should align inside the body and which barbs it should be between when the gun is at rest with the trigger released. (Click the image twice for a high resolution version).



    There are 5 holes on top of the three way, the middle three plugged by barbs connected to hoses, and the two very end ones open as vents. Air may also leak from the end of the three way at the adjuster end (nearest the muzzle) and from the threaded end (nearest the grip frame).

    A leak along the three way shaft coming out at either end means the o-ring on the end that is leaking is bad (this is only true if the timing is correct as above, if your timing is wrong adjust it to be correct and then check again). Replace the relevant o-ring and test again.

    The rear hole is the rear vent and a leak there can have a few different causes.

    1) Most common is the timing. If tweaking the timing rod slightly forwards or slightly back doesn't affect the leak in any way (either stopping it, or increasing it, or getting rid of it) then we can move on to something else. For a hinge frame set up a leak here means either the middle three way o-ring is bad, or the RAM piston o-ring is bad, or the ram piston seal to shaft is bad. For a slide frame a leak at the rear vent is often accompanied by a leak along the shaft and out towards the frame of the gun. This means the rear o-ring on the three way stem is bad.

    2) When the trigger is pulled and the bolt goes back does the leak stay? Does it come out of the same hole? Does it go away? Does it move to the front vent hole? If it goes away it's likely timing. With a hinge frame If it goes to the front vent hole it is either the middle three way o-ring or the ram (more on that shortly). If it is now out of both front and back vent holes it is also the rear three way o-ring, as well as the middle one and/or the ram. With a Slide frame if it goes away then the o-ring nearest the frame was bad.

    3) So if the above issues doesn't fix it for a gun using a hinge frame and the leak moved from the front to the back of the three way and wasn't fixed by swapping the middle shaft o-ring (and the gun is timed moderately) then it's for certain in the ram. There are two places in the ram that can cause "blowby" and a leak at the three way that have nothing to do with the three way. 1) is the ram piston o-ring. Which is a 010 o-ring in buna at 70 durometer. The second is between the piston head and the ram shaft which is installed and sealed permanently at the factory. It shouldn't be that, but it has happened in the past. Initially I would try replacing the piston o-ring and using dow 33 grease. We do run all o-rings to be very light fits as compared to industrial standards, so if that doesn't work use dow 55 grease and leave it overnight before airing it up. If that doesn't work then it may be the piston to shaft seal. The ram piston would need to be removed and new sealant would need to be applied. This needs to be a strong connection because of all the impacts back and forth.

    The very front hole is the front vent and a leak there can have a few different causes. It's pretty much the reverse of what you would find above depending on your frame, but we will repeat ourselves here to try and help make it clear.

    1) Most common is the timing. If tweaking the timing rod slightly forwards or slightly back doesn't affect the leak in any way (either stopping it, or increasing it, or getting rid of it) then we can move on to something else. For a Slide frame set up a leak here means either the middle three way o-ring is bad, or the RAM piston o-ring is bad, or the ram piston seal to shaft is bad. For a Hinge frame a leak at the front vent is often accompanied by a leak along the shaft and out towards the adjuster of the three way. This means the front (closest to the allen key end) o-ring on the three way stem is bad.

    2) When the trigger is pulled and the bolt goes back does the leak stay? Does it come out of the same hole? Does it go away? Does it move to the rear vent hole? If it goes away it's likely timing. With a Slide frame If it goes to the rear vent hole it is either the middle three way o-ring or the ram (more on that shortly). If it is now out of both front and back vent holes it is also the front three way o-ring, as well as the middle one and/or the ram. With a Hinge frame if it goes away then the o-ring nearest the adjuster was bad.

    3) So if the above issues doesn't fix it for a gun using a slide frame and the leak moved from the front to the back of the three way and wasn't fixed by swapping the middle shaft o-ring (and the gun is timed moderately) then it's for certain in the ram. There are two places in the ram that can cause "blowby" and a leak at the three way that have nothing to do with the three way. 1) is the ram piston o-ring. Which is a 010 o-ring in buna at 70 durometer. The second is between the piston head and the ram shaft which is installed and sealed permanently at the factory. It shouldn't be that, but it has happened in the past. Initially I would try replacing the piston o-ring and using dow 33 grease. We do run all o-rings to be very light fits as compared to industrial standards, so if that doesn't work use dow 55 grease and leave it overnight before airing it up. If that doesn't work then it may be the piston to shaft seal. The ram piston would need to be removed and new sealant would need to be applied. This needs to be a strong connection because of all the impacts back and forth.

  2. #2
    So to simplify everything.

    1) Do you have adequate air? Y/N
    2) Do you have the LPR set high enough? Y/N
    3) Do you have the timing approximately right (enough that the gun will cycle)? Y/N
    4) Are you certain of where the leak is? Y/N

    If you didn’t answer yes to all of the above then you need to go back and fix those issues before moving on. After you are able to answer yes to the above
    5) Are you using a hinge or slide frame?
    6) Does the leak go away when you pull and hold the trigger? Y/N
    7) Does the leak move from one vent hole to the other when pulling and holding the trigger? Y/N

  3. #3
    Insider PBSteve's Avatar
    Join Date
    May 2012
    Location
    Los Angeles
    Posts
    3,084
    You might consider posting/stickying this to the PBN forum as well. http://www.pbnation.com/forumdisplay.php?f=235
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

  4. #4
    Quote Originally Posted by PBSteve View Post
    You might consider posting/stickying this to the PBN forum as well. http://www.pbnation.com/forumdisplay.php?f=235
    I had it in our Inception forum there, but also just copied it to the mech cocker forum as you suggested, thanks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •