749 Brake Master Cylinder Leaking ?

Discussion in '749 / 999' started by DucRod, Sep 22, 2016.

  1. Hello all I have been doing some maintenance recently and discovered that the triangular shape master cylinder is leaking at the insertion joint on the brake master cyl.
    It looks like the resevoir loosens off as i can push it back nto place the Allen headed bolt does not hold it so....... I have decided to fit a remote resevoir has anyone got any info or pics of any mods already done ? Just after a few pics to see what it would look like . will probably do the clutch master next to match.

    I actually like the master resevoirs shape but they do seem a bit loose when fitted may be its worn through age.
     
    #1 DucRod, Sep 22, 2016
    Last edited: Sep 24, 2016
  2. Ok tried to fit a remote resevoir on the 749 plenty of room and looked ok. But ! The original master has a bleed screw inside it and the theory is to replace it with a bleed nipple of standard size and shape. All good you think. No the sandard resevoir is held on with a large Allen key bolt this needs to go back on the bleed nipple screws in to this but it sits too deep and causes por fluid flow into the master cyl. So no bleeding of brakes.

    Back to the drawing board.

    On reassembly I cleaned the aluminium corrosion from in the area where the resevoir plugs in to the Master cylinder seal this combined with crystallised mix of fluid and corrosion caused the seal to be moved from its outer edge and allowed the fluid to seep out slowly. A thorough clean and lube with rubber grease sorted it . The master cyl resevoir pushed in alot tighter and no leaks so for now the original master resevoir is back on.

    No more leaks fingers crossed.
     
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  3. Thats a good set up but I did not do anything wrong I know what was causing the problem I did not fit a proper bleed nipple as you did due to not having one at the time. But as it happens the clean out of the resevoir entry point and seal has sorted it all . I actually lke the standard resevoirs so it works for me but yours is a good job and look well if I have any more issues I will convert as you have .
     
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