Date: Fri, 30 Jan 2004 11:08:45 -0000
Reply-To: Tony Polson <tp@WHSMITHNET.CO.UK>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tony Polson <tp@WHSMITHNET.CO.UK>
Subject: Re: wierd brake stuff :-(
Content-Type: text/plain; charset="iso-8859-1"
Adam B wrote:
>
>After I got my front rotors and pads and rear wheel
cylinders replaced (all
>OEM parts) a couple months ago, my brakes are doing this
wierd thing. When I
>press the brake pedal in, it goes down quite far and the
brakes do not grip
>as they should. When I push the pedal down, bring it up,
and push it down again,
>the brakes grab real hard. My friends suggested that it was
the master
>cylinder (I sure hope not because of the price), and that
was also my mechanics first
>impression. I took it back to him and he bled the system
again, and then said
>how it was my emegency brake cable not functioning
properly. My knowledge was
>that the emergency brake is a mechanical device and not
related to the
>hydralics at all. Anybody know what this could be? Or maybe
just an
>explanation of how the e-brake works? Or how I could
service it myself?
Hi Adam,
You have the classic signs of air in the system meaning that
the brakes need to be bled properly. It would appear that
your mechanic has been less than thorough. The emergency
brake should have no effect unless something is seriously
wrong.
The brake system has two circuits. Both need to be bled.
It is no good bleeding just one.
Except on early air-cooled Vanagons, the clutch is also
hydraulic. It shares the same hydraulic reservoir as the
brakes, located behind the instrument panel. The clutch
circuit should be bled at the same time as you bleed the
brakes. (Likewise, every time work is done on the clutch
hydraulics, the brakes should also be bled.)
You can bleed the brakes yourself. It is easier to do it
with a friend but it is perfectly possible on your own if
you use a "one-man brake bleeding kit". This has a neoprene
bleed tube with a non-return valve in it. That's what I
use; the last time I needed help bleeding my brakes was 30
years ago, and that was just before I bought my first kit!
I would start with the clutch, then bleed the wheels in
pairs, front and back. The kit will probably include
comprehensive instructions. But basically you put the tube
over the bleed screw, which you then loosen by half a turn.
Four or five *slow*, full pedal strokes (also go slowly when
allowing the pedal to return upwards) will expel the
contaminated fluid and replace it with fresh.
The non-return valve in the tube stops the old fluid, and
air, getting in. You then tighten the bleed screw (don't
over-tighten as they snap easily) and move on to another
wheel. Make sure you keep topping up the brake/clutch fluid
reservoir at all times during the bleeding operation,
otherwise air will get in and you will have to start again.
There's a very good chance that careful bleeding will
completely solve the problem. Also, only when the brakes
and clutch have been properly bled will you be able to
diagnose whether anything else is wrong, so bleeding is
always what you do first.
Good luck!
Tony
'95 VW Caravelle
