balance, thank yous

[Bernie Benz]

Brett,  Good write up.  Hope the it, along with  my "constructive" comments,
will be of value to others

> From: Brett Dikeman <brett at cloud9.net>
> Date: Thu, 11 Apr 2002 20:42:58 -0400
> To: quattro at audifans.com
> Cc: 200q20v at audifans.com
> Subject: balance, thank yous
>
> It's funny how things get out of whack but balance each other out.
After reading this post, I don't understand what, in your opinion, is
balancing out what.
>
> After finally getting the Big Baby back on the road after the
> complete rear brake job(both sides, near complete teardown, new
> pads/rotors), I couldn't figure out for the life of me why it was
> suddenly pulling to the right...  ...and then I remembered.  No
> dragging caliper on the left side :-)  Time for an alignment, I guess.
It may well be time for an alignment but, IMO, not relevent to the rear
brake overhaul
.
> The journey continues.  Just as well; I need to have the balance
> checked on the summer wheels, since things get pretty...exciting...
> above 75-80mph.  I sure hope one isn't bent.
>
> It could be that I haven't driven the car in 2 weeks and have
> adjusted to the Volvo's neck-snapping brake pedal response, but the
> brakes seem too squishy; I did a complete pressure bleed this evening
> of the rear circuit
No such thing as a complete brake bleed, of just half of the hydraulic
circuit.
> (almost 1 liter used, right on spec with the
> Bentley's guide for how much it takes to flush each side), but I
> suspect the real reason is the fronts -really- need work too.  Here's
> hoping I don't need a set of front pads in addition to the rotors,
> since all I have at the moment are new front rotors.
Don't replace rotors, front or rear, without very good reason!  The used
rotors have worn true and will prove to be superior to any new ones.
> Still, I'll probably gently drive the car around town a few times
> over the next few days and rebleed a little to see if any more air
> bubbles pop out of various hiding places in the caliper.
Try bleeding all 4 next time.
> I might also try doing the bleed with the drill bit on the
> proportioning valve to get more flow.
For sure, an 1/8" hole through the proportioning valve will "get more flow",
but what's this snake oil suggestion all about?
>
> One question for the group...when pressure bleeding it(used about
> 15psi), I would occasionally stomp on the brake pedal, and I'd get,
> shortly thereafter, a flurry of bubbles, but I wasn't sure if I was
> moving air out of the caliper/line or sucking air back into the
> caliper on the upstroke and then forcing it out slowly because of the
> bleed.  Doesn't seem like it, since I could stomp, hold for several
> seconds, then run over to the wheel and the bubbles would be pretty
> far down the line, rather than just coming out the tube, but I
> thought I'd ask.
I'm not a hi pressure bleeder but, when using atmospheric pressure bleeding,
one certainly can draw air into the caliper on the master cylinder return
stroke from around the loose bleed screw even with a tight plastic tube from
bleed screw to sump.  To do it right one must open the bleed screw for the
down stroke and close it prior to the return stroke.  I find that
atmospheric pressure bleeding usually works well without pumping, just takes
a little longer.
>
> Lastly, a huge thank you to all who responded over the last
> week/week+half to various "first serious brake job" questions(why I
> cc'd both lists, questions ended up on both.)
IMO, yours apparently was a half brake job, not so serious.

> Certainly learned a lot(like, for example, ebrake cables get attached
> BEFORE you mash the brake pedal to get the calipers adjusted to the
>pads/rotors.)
More snake oil?  If the hand brake levers are against their stops the
hydraulic system neither knows nor cares anything about the hand brake
system.

But you got your hands dirty and had fun, right?  Great!

Bernie