Berkeley 12 JG Pump Assembly (Cap Gap?)
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Berkeley 12 JG Pump Assembly (Cap Gap?)

  1. #1
    Steve
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    Default Berkeley 12 JG Pump Assembly (Cap Gap?)

    I'm in the process of rebuilding my first Berkeley Pump, in trying to seal up the back cap it appears as though I have to much of a gap. It looks like the lip on the inside of the cap is hitting the bearing before it can seat. I took some measurements to test this, and unless I'm crazy I need a narrower bering (hope not, because I'd have to have it pressed off/on) or a thicker gasket to account for this. I'm curious if anyone knows the specs on this pump, and if so how I fair against them. I can't imagine anyone cut down the back of this thing, but you never know.

    hole in pump case = 1.510
    Barring width = 1.370
    depth of cap lip = 0.190
    Gasket = .0126
    .041 @ 17 ft/lbs
    - .0126 gasket
    ==========
    Gap = .0284

    If that math is right, I have no clamp pressure on the gasket at that width which is accurate because torqued down without the gasket I can slip it in the gap 0.43
    -Steve
    '73 Tahiti

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  3. #2
    Senior Member jetboatperformance's Avatar
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    Steve , assuming I read this correctly unless "something has been machined , ground on or changed on your suction or cap or...?? you have the wrong bearing (whcich is not likely) I would suspect that your bearing is not back far enough in the bearing cavity (a burr or obstruction ?) There should be sufficiant recess at the front of the suction/bearing area to allow for the cap register to both crush/support the gasket as well as hold the bearing Call me if I can help Tom 805 466 4719

  4. #3
    B1 Racing cs19's Avatar
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    Assuming your bearing cavity does not have any burrs or obstructions... You need to re-machine the bearing cap or get a thicker gasket if possible. Setting this clearance is done in a pump overhaul usually. The clearances from the factory are not correct in most cases and you are correct alot of times you wont have any clamping on the gasket..If the gap is .028 now a .033 gasket would be ideal or re-machine so you have a few thou of clamping on your .012 gasket. Your .012 gasket sounds very thin, they are .030 usually, if its one of those yellow/gold old skool berkeley gaskets get a new one.

    Good luck with it.

    Chris.


    Quote Originally Posted by stevem View Post
    I'm in the process of rebuilding my first Berkeley Pump, in trying to seal up the back cap it appears as though I have to much of a gap. It looks like the lip on the inside of the cap is hitting the bearing before it can seat. I took some measurements to test this, and unless I'm crazy I need a narrower bering (hope not, because I'd have to have it pressed off/on) or a thicker gasket to account for this. I'm curious if anyone knows the specs on this pump, and if so how I fair against them. I can't imagine anyone cut down the back of this thing, but you never know.

    hole in pump case = 1.510
    Barring width = 1.370
    depth of cap lip = 0.190
    Gasket = .0126
    .041 @ 17 ft/lbs
    - .0126 gasket
    ==========
    Gap = .0284

    If that math is right, I have no clamp pressure on the gasket at that width which is accurate because torqued down without the gasket I can slip it in the gap 0.43
    Last edited by cs19; 06-05-2009 at 07:54 AM.
    B1Racing.net

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  6. #4
    Steve
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    Thanks for the input, I was double checking my measurements and the gasket is actually .0196, I was miss reading the line and it landed a little before .02 so it .0196.

    Gasket = .0196

    At any rate, its clearly a bit thin so I'm going to do some calls on Monday and see if I can find a thicker gasket. Can these be doubled up if necessary (.0392)?
    -Steve
    '73 Tahiti

  7. #5
    Senior Member jetjunky's Avatar
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    Quote Originally Posted by stevem View Post
    Thanks for the input, I was double checking my measurements and the gasket is actually .0196, I was miss reading the line and it landed a little before .02 so it .0196.

    Gasket = .0196

    At any rate, its clearly a bit thin so I'm going to do some calls on Monday and see if I can find a thicker gasket. Can these be doubled up if necessary (.0392)?
    Yes, stacking gaskets is not unusual in some cases, shoot for .005-.010" crush on cap. (.005 prefered) However, follow former recommendations to verify proper seating of bearing on shaft and in housing 1st, then work with gaskets for sealing pressure. If the bearing can move it can contact the wear ring and take it out, so proceed with caution, get help if needed, it's usually cheaper and less disappointing. I call it the high cost of education. haha. Good luck, have fun, be safe.

  8. #6
    B1 Racing cs19's Avatar
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    Quote Originally Posted by stevem View Post
    Can these be doubled up if necessary (.0392)?
    I wouldnt do that, do it right and machine the cap so things fit with a single gasket. Like mentioned before shoot for .005 crush on that gasket.
    B1Racing.net

  9. #7
    Steve
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    Quote Originally Posted by cs19 View Post
    I wouldnt do that, do it right and machine the cap so things fit with a single gasket. Like mentioned before shoot for .005 crush on that gasket.

    Quick followup [Yes its been this long since the pump finally got together ], I followed this advice and wound up having a local pump shop with better tools then and eyes then I shave the cap down to fit. Looks good now, thank you to all who provided imputed.
    -Steve
    '73 Tahiti

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