[V8] Bleeding the brakes

[cobram@juno.com]

"Coleman, David" <David.Coleman at blackrock.com> writes:

> Absolutely you can bleed the brakes w/ a friend working the pedal. 
> The only danger is if helper buddy is too brutal when pumping, which 
> can damage the master cylinder seals.  

It's possible, but I've never seen this happen.  If it does happen the
master was probably already marginal, better to find out with the car in
the driveway than the highway.
 
> Crack all the bleeders and let gravity work while you call a friend, 
> neighbor, or mildly gifted  orangutan. 
> After the gravity bleed barely does anything after 40 hours of 
> standing there,

I don't think Germans believe in gravity.  This works on many an American
or Asian car, but never seems to do much on German iron.  Pressure
bleeders will work. With vacuum bleeder on an Audi, I always end up
manually bleeding anyway.

> have buddy SLOWLY + GENTLY depress the pedal about 
> 3/4 of the way down and hold. 

The pedal should be pumped at least 3 times before you yell "hold".  The
idea is to remove all the air/vapor from the line, this is better done if
the line has at least 3 pumps of pressure in it, for obvious reasons. 
The assistant should hold pressure on the pedal, irregardless of how far
down it's gone (unless it's bottomed out of course).  If the assistant is
a novice or available orangutan, maybe telling them to "keep pushing"
might be better than "hold".  You should only be cracking the bleeder
screw about a 1/4 turn for a second or less, the more pressure at the
bleeder the better. 

>Crack the r/r caliper screw to purge, 
> then snug back up. Buddy then gently releases. Repeat until the 
> fresh stuff comes out. Move around the car to the left rear, r/f, 
> then l/f.  

The actual sequence isn't that critical to bleed results, but does keep
cross contamination at a minimum.  Good rule of thumb, that's easy to
remember is "farthest to the closest", start with wheel farthest from
driver and work your way closer.  This works even for listers who drive
on the "correct" side of the road, as they put it. ;-)  There are
vehicles out there where there is more brake plumbing closer to the
driver than farther, but nothing listers here will probably come across.

> No jumping up and down on the pedal -- just down once and 
> hold. 

Pump, not jump.  (insert funny remark here)

> After all have been done, you can go back around, to the 
> fronts at least, and do the pumping thing, albeit gently...

You should pressure bleed the rears and the fronts.

BCNU,
http://www.geocities.com/cobramsri/
May we dance with your dates?