Just air in the system or a bad master cylinder?

[boston813roc at gmail.com (brad boston)]

Dan,

With all the fluid under the car it was hard to tell if there were leaks but
I checked for it and could not find any.

I am able to pump up the system with a few pumps.  when I first installed
everything it would take 4-5 pumps to get a firm feel but now it only takes
2-3 after priming the master clylinder

The MC was a new one and therefore should not have the problem of ripping up
the seals by over traveling it, but I could have and it may be the next
place to look. (does any one have a known good that I could try before I buy
another one?)

Bryan,

As I stated above I can pump up the system with a few pumps but there is no
damping force on the first pump as far as I can tell.

I am fairly sure that everything is lined up right since it (almost) works

Brad

On 11/16/06, Dan Bubb <jdbubb@verizon.net> wrote:
>
> I assume there are no apparent leaks anywhere.
> I would think that with all the bleeding you've done that even if there
> was some air in the system you would still be able to pump up the pedal and
> get some sort of pedal height just by pumping the pedal very fast multiple
> times. If you can't even do that then your MC is probably toast.
>
> You didn't say if the replacement MC was a new unit or not. Used brake
> components tend to build up crap and crud on the surfaces that are not swept
> by the pistons and seals. If you then make the piston travel further than it
> generally has (such as when bleeding the system and using full strokes) the
> seals are dragged across the crud and can be damaged.
> So, manual bleeding with a used MC has a pretty high chance of damaging
> the MC seals unless the system that it came from was well maintained and had
> the fluid replaced regularly.
> Unfortunately I've also damaged a brand new MC by manual bleeding.
> I personally don't think priming or bench bleeding the MC is necessary.
> I do highly recommend using a power bleeder! They aren't that expensive,
> avoid potential damage to even a new MC from manual bleeding and turn
> bleeding A3 calipers that need to turned upside down to bleed into a one man
> job!!
> HTH
> Dan
>
> From: "brad boston" <boston813roc@gmail.com>
> Sent: Thursday, November 16, 2006 12:39 PM
> Subject: Just air in the system or a bad master cylinder?
>
>
> > The saga continues...
> >
> > thus far in our story the shade tree mechanic (me) and his trusty side
> kick
> > (a friends that brings cold beer) have had no luck in getting the brake
> > system to work on my (now garage queen) '88 16v.
> >
> > the Things that have changed or had done to it are as follows
> >
> > Replaced the rear calipers with some sweet looking red powder coated
> ones
> > (thanks Peter)
> >  This got the E-Brake working and was the initial cause of this
> adventure
> >
> > Replaced the front calipers with nice red ones so everything would match
> > (they look great on the car)
> >  Tried to bleed down the system but the pedal went right to the floor
> after
> > bleeding all four calipers :(
> >
> > Though it was the master cylinder so I ordered a new one and some
> stainless
> > Steel lines just because I already had the system apart.
> >
> > Tried to rebleed the system but again no luck
> >
> > Asked for help and found that the master cylinder needed to be primed
> before
> > it is installed
> >  used a short piece of brake line and some tubing to bleed each outlet
> of
> > the master cylinder (This got a lot of air out)... But still the pedal
> goes
> > right to the floor
> >
> > Tried to rebleed the system at all the calipers but still nothing
> >
> > I am starting to think that I may not have gotten a good master cylinder
> or
> > that there is some air in the system that I was not able to get out even
> > with repeated bleedings
> >
> > OK, so what do you all think?  Should I try rebleeding the master
> cylinder?
> > Try replacing the master cylinder with a known good one? (any one have
> one I
> > can borrow?)  Any other ideas or suggestions would be appreciated.
> >
> > Tune in next week to find out if the shade tree mechanic will be ready
> to
> > take the scirocco out for the winter season of auto x.....
> >
> > Brad
> > _______________________________________________
> > Scirocco-l mailing list
> > Scirocco-l@scirocco.org
> > http://neubayern.net/mailman/listinfo/scirocco-l
> >
>
>