Re: Flushing Brake Fluid

[jack@domain.elided (Jack Hagerty)]

>From: Scott Fisher <sefisher@domain.elided>

>One of the things I learned was that Alfas with dual-circuit braking
>systems are bled in a slightly different way from single-circuit cars. 
>I'm not sure when the changeover happened at Alfa; in most cars it was
>around 1968, so your '71 *probably* has the dual-circuit master
>cylinder.  

Actually, Scott, in '71 Alfa may have still had the dual single-circuit
master cylinders. I don't remember exactly when they got rid of that 
abortion, but it had two master cylinders, each with its own little vacuum 
booster.  It may have been gone by '71. I know it was still around in '70.

The rest of your bleeding procedure is the traditional approach. The 
one thing you left off is that you usually start with the wheel that's 
furthest from the master cylinder (i.e. right rear) and work your way 
closer. The way you did it is usually necessary if you have to remove 
air from the system (presuming you don't have a pressure or vacuum 
bleeder), but if you are just changing the fluid due to age in an 
otherwise correctly working system I have an easier way.

I usually do this as part of a larger routine maintenance session so
the car is up on jacks (ahem) and all the wheels are off. Take a turkey 
baster and suck all of the old fluid out of the reservior. Don't worry, 
you can't suck out enough to get air into the M/C. Wipe the black slime 
off of the inside of the reservior as much as you can reach, and refill. 
Go to the right rear cylinder and open the bleed nipple. That's it, no 
hoses, no pumping, no Busby Berkeley coordinated Open-down-Closed-up hands 
and feet motions. I put a jar under the dust shield to catch the fluid
as it runs down the back. I go about my other tasks keeping an occasional
eye on the reservior to make sure it doesn't get too low. When the 
fluid dripping down is clear (like you said) I close that valve, wipe
off the shield and move to the left rear and repeat. Then the right front 
and finally the left front. 

The first one takes a long time since you are changing the entire line 
from the M/C to the wheel. The second one is much shorter since it's only 
the short piece of pipe from the split on the differential to the wheel. 
The two front ones are somewhere in between and roughly equal.

This works for clutches, too.

- - Jack

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| Jack Hagerty                |    "If this rocket stuff is so important    |
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