Water pump internals | FerrariChat

Water pump internals

Discussion in '308/328' started by topley, Aug 27, 2025.

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  1. topley

    topley Karting

    May 10, 2022
    91
    Los Angeles
    Full Name:
    Jay Barton
    Trying to identify what I should have. This came out of my 81GTSi that I have been driving for 3.5 years. The weep hole had been siliconed shut many years ago by the looks of it. Not a surprise that by the time it started leaking it was crazy shot… So obviously it’s a large bearing pump but with 3 bearings. There was no spacer ring between the c-clip and inner most bearing and no spacer tube between that and the outer bearing. I’ve been searching and not seen exactly this… was it bastardized? And if so what should it have? Seems rebuildable if I use the original style seal?
    Thanks
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  2. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
    4,286
    Black Forest Germany
    Full Name:
    Martin N.
    #2 Martin308GTB, Aug 28, 2025
    Last edited: Aug 28, 2025
    Yes! Rather! Maybe you can convert from the late two-piece-seal to the one and only reliable one-piece-seal.

    Can you show another picture with the back of the impeller?
    The "washer" between circlip and and inner bearing actually is a leaf spring washer. The spacer between inner and outer bearing is a simple part everyone with a lathe can make in ten minutes.(ID 15mm, OD 20mm, L=36mm

    Best
    Martin
     
  3. topley

    topley Karting

    May 10, 2022
    91
    Los Angeles
    Full Name:
    Jay Barton
  4. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
    4,286
    Black Forest Germany
    Full Name:
    Martin N.
    #4 Martin308GTB, Aug 29, 2025
    Last edited: Aug 29, 2025
    It's unnecessary, because with the big bearings pumps the seal was the problem, not the bearings. And a leaking seal with a clogged weep hole destroys the bearings. No matter how many.
    But when someone insists on a third bearing, what makes the whole situation statically overdetermined btw, you even need two spacers, 11.5mm long each. See my CAD screenshot. Without spacers it is a complete hack job and I wonder, how the pulley can be fastened tightly. Without spacer(s) between the inner bearing races you would simply push in the outer bearing while tightening the pulley nut. In the end the pulley would collide with the housing. Sorry, but someone in the past was completely unaware about what he was doing with your pump.

    See also my last posts of this thread on page 4 for what you need for a rebuild.

    https://www.ferrarichat.com/forum/threads/water-pump-rebuild.362611/page-4

    Three bearings draft with inner race spacers:

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    or like this. But then i would rather look, whether there's a two-row bearing in the needed ID and OD and adjust the spacer's length accordingly:

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    Best from Germany
    Martin
     
  5. topley

    topley Karting

    May 10, 2022
    91
    Los Angeles
    Full Name:
    Jay Barton
    Thanks Martin, this makes a lot of sense. I’m amazed as that water pump lasted for a long time like that even though it was probably failing for years.
     

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