Brake Bleed Q:

[Bernie Benz]

Come on Scott!

You've been on this list a long time, why all this P&Ming?  What some won't
go through just to avoid a complete hydraulic system overhaul!  Any
maintaince history, or are you just pulling the list leg?

Bernie

> From: SuffolkD at aol.com
> Date: Tue, 7 Sep 2004 22:47:40 EDT
> To: 200q20v at audifans.com, quattro at audifans.com
> Subject: Brake Bleed Q:
> 
> 
> I smoked the Right rears on the 200 20V on the last laps at a DE.
> The rears are solid disc.
> 
> 200 20V 1991 Solid rears.
> The pads were NLA.........just the backing plates which made stone grinding
> sounds. OUCH!
> 
> Fastforward to R&R on a dirt road.....(Planned......added for dramatic effect)
> Since I just bought the pseudo correct metalnerd tool to push in the pistons
> I was met with a LOT of resistance.
> ( I did crack the bleeder to try an help pushing the piston in.............)
> I suspected the piston was so far out it was cocked at an angle and jamming.
> Situation was resolved by detaching the caliper / hose /line and finishing on
> a vise where alignment was right on.
> The piston turned in ridiculously easy then.
> 
> Problem:
> During the re bleed of the rears, following the Bentley which outlined the
> typical RR, LR, RF, LF format I found very little fluid coming out.
> 
> I used a pressure bleeder which was sort of a problem in adjusting the RR
> caliper piston back out to the pads on the rotor.  This created a vacuum where
> the piston retracted when the brake pedal was released from the floor.
> Pressure 
> @ 15 lbs didn't push it out.  So I used the Ebrake cam which did an excellent
> job a ratching it out when I was first trying to  push it back in with the
> metalnerd tool....................but NOT in trying to ratch out the piston to
> take up the slack between the pads and the rotor.  (used thin pads here 10 V
> avant ones)  I resorted to the old fashoined pedal to the floor, crack
> bleeder, 
> tighten release brake pedal from floor, method.
> 
> So my Q's are:
> 1:  Is there an additional step I'm missing with the ABS controller not
> allowing fluid to "pour" out when I crack the bleeder screws?  This is on the
> rears..........
> 2:  MC the issue?
> 
> 3:  Does the piston have to come out to replace the piston boot?

> 
> I never touched the fronts, and drove the car back home to finish work on it
> ( no new rear pads) 10V avants' fit though...................Good but spongy
> brake pedal.
> 
> I considered the fronts and rears to be on different circuits as there are
> two steel lines from the MC to the ABS.
> (Did they do away with the diagonal braking system the old 5000's had?)
> 
> Other considerations:
> Ebrake cables loose to console lever.  (Need adjustment)
> Mid Atlantic car no corrosion on any component except the caliper cast
> surfaces......
> Rear (RR) pad wore inner and out, rotor is a tad thinner on the inside
> (thickness) outside looks new.
> Guide pins and boots in tact, free sliding.
> Fluid was dark with no clouding or junk in it, consistent with High temp
> -HEAT- fluid discoloring (in the caliper)
> MC is flaky causing drag on all four brakes when HOT,  Bleed was cold: two
> days sitting, no binding.
> 
> TIA - Scott by BOSTON
> 
> _______________________________________________
> 200q20v mailing list  http://www.audifans.com/mailman/listinfo/200q20v