Endless water pump seal questions | FerrariChat

Endless water pump seal questions

Discussion in 'Boxers/TR/M' started by JohnMH, Nov 12, 2021.

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  1. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    Hi, I am getting tired of wrestling with water pump seal issues.

    My car is a 91, 91626, with engine 20382.

    It has an impeller with a recess in the back which would fit a 2 part seal.

    I understand that seal 152051/A is the correct one for an early engine which would normally have the 2 part seal.

    When I install seal 152051/A properly, the top of the seal is flush with the end of the tapered spacer which fits over the shaft. At that point, 5mm of square water pump shaft is sticking out of the seal. The problem is that the square portion of the hole in the impeller is 8mm deep. So the impeller never sits flush with the end of the square part of the shaft and the impeller nut barely threads onto the shaft.

    183759 only fits engines after 20821, so what gives?




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  2. vincenzo

    vincenzo F1 Rookie

    Nov 2, 2003
    3,373
    As i understand it, your impeller is an early version. Suitable for the 2 piece seal. This one is off my ‘90 sn83958.

    note that there are two versions of the collar (aka spacer). Sounds like you may in unchartered territory with a mix and match assembly. Was the previous seal like the one you are putting in now?

    i believe the design intends to slightly compress the seal’s spring upon the impeller install. If i catch your text correctly, your situation will compress the seal spring 3mm (8-5). That sounds a bit excessive…. not not exorbitant. Any idea how well centered (longitudinally) the collar is inside the oil seal?

    perhaps call ricambe or the dealer and ask if they could measure the impeller similar to the one shown here.

    anyway…. No definitive answer for you but this may be of help.
    View attachment 3234781
     

    Attached Files:

  3. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    Thanks for the information and the photos. I noticed a scratch on the original inner sleeve and replaced it... with the wrong one. At least I found the error.

    It may be 5-10 years before I do this again. I will take excellent notes and put them somewhere where I can find them.

    On the positive side, I only had one intake valve in need of very minor adjustment (shim removal is easy) and the clutch installation seems pretty straightforward.
     
  4. qwazipsycho

    qwazipsycho Formula 3

    Oct 30, 2004
    1,176
    Utah
    Full Name:
    Scott
    FWIW - I replaced my 2 piece seal 8 years ago and it's still holding strong.
     
  5. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    As I split the engine from the transmission for the purpose of replacing the oil pump chain and tensioner, leaving it alone was not an option (and the oil seal behind the water pump seal was dried out and failing).

    This major service has involved the water pump, differential and clutch, which has taught me more about my TR than I ever knew (or at least exposed my ignorance).
     
    c4b4the04 likes this.

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