Bleeding dual cct brakes

["Graham Hilder" <graham.hilder@domain.elided>]

Evening all,

In Digest 926 Biba notes that discussing methods of bleeding all brake =
circuits at once aren't all that riveting a topic, and that he's happy =
enough do one at a time and open & close the bleed screw as the  helper =
operates the pedal. Oh well, for sure, it's hardly a an exciting topic, =
can't argue with you there, but then it's hardly an exciting job either, =
and it's one I'd rather get over and done with as quickly as poss rather =
than prolong it. Especially when there's a number of Alfas to look after, =
2 or 3 of which see a fair bit of track time and need rather frequent =
change-outs of cooked brake fluids; in total this makes for quite a lot of =
fluid changes per year and really you don't want to be spending longer on =
each one than you need to.  And if it's the 6-screw Alfetta you're doing, =
you don't really want to make your beautiful assistant hang around =
twiddling her thumbs as you grovel around on the floor swapping hoses and =
jars and spanners while saying Only 5 More To Go Now Dear!   Even love has =
its limits!  =20

Biba akso mentioned "My theory is that air is sucked back up the threads =
of the bleed screws when the pedal is released .....(snip)..... when =
released, the fluid which has worked itself down the threads is sucked =
back up and air is liable to enter the chamber."   Well, as Biba said, it =
seems to work for me..... I think the key is to ensure that there are at =
least a few inches of bleed tube sloping upwards from the screw before =
allowing it to droop down to the drain jar. That way there is guaranteed =
to be continuous fluid in the tube above the screw mouth and that's what =
ought to be drawn back in upon pedal release.

And to Jack (in no. 927)....... yes good point Jack about pumping the old =
reservoir fluid out through the system...... maybe I should think again on =
that.   Might be time for me to dig out the ol' turkey baster myself.

Graham Hilder,
N.Z.
(Alfasud, GTV, Alfetta GT)

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