Date:         Thu, 29 Jan 2004 23:10:47 -0700
Reply-To:     Keith Hughes <keithahughes@QWEST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Keith Hughes <keithahughes@QWEST.NET>
Subject:      wierd brake stuff :-(
Content-Type: text/plain; charset=us-ascii; format=flowed

Hi Adam,

> 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=20
> 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=20
> cylinder

Not likely at all. Master cylinder failure *most* often (barring
external leakage) results in a *hard* pedal, with minimal actual
braking. If the piston seals are leaking by, you'll get a 'bleed
down' effect where the pedal will be firm initially, then slowly
sink as you press it down hard.

> (I sure hope not because of the price), and that was also my mechanics first
> impression.

I'd find another mechanic - seriously, at least for brakes.

I took it back to him and he bled the system again,

Which only makes sense *IF* the pedal height increases as you pump
it, *AND* it continues to have a 'spongy' feel. If it's hard and
firm, it's not air.

> and then said how it was my emegency brake cable not functioning properly.

*Definitely* get a new mechanic! This is complete, utter BS. We're
talking BS with whipped cream and a cherry on top, chopped
walnuts, and a crumpet!

> My knowledge was
> that the emergency brake is a mechanical device and not related to the
> hydralics at all.

Absolutely.

Since you just replaced the brakes, it is almost certainly the
rear brakes out of adjustment (too loose). The first time you
press the pedal, the shoes are pressed outward as far as the
hydraulics (volumetric fluid displacement) allow. If you then
press the pedal again, relatively quickly, the master cylinder
will 'reset' quicker than the springs on the brake shoes can force
the fluid out of the wheel cylinders (not fully returning to the
'rest' position, so they 'start' out closer to the brake drum), so
the next press of the brake pedal pushes them against the drums
firmly, the pedal feels firm, and you have good braking.

IMO, *any* professional mechanic that doesn't understand this
should be studiously avoided.

Keith Hughes