[urq] MB brake question

[Patrick Carlier]

It's the master cilinder !
I've seen it before on an audi200 ( 5KQ ) .
The brakes would bind occasionally , but only in the summer with
the airco engaged . Without the airco the problem didn't occur .
It has to be the extra heat that somehow blocked the master cininder .

If the brakes binded , a wet cloth around the master cilinder to cool it
would release them immediatly .

Opening , cleaning and greasing the master cilinder didn't help .
The internals looked perfect though .
To be absolutely sure , I've rebuild the four calipers .
Didn't help either .

So I finally put on another master cilinder , and the problem was gone
and has never occured again .

Sadly there's no gasket kit available so replacing it was the only option .

Pat




----- Original Message -----
From: "Johan Hisinger" <milisen at hotmail.com>
To: <urq at audifans.com>
Sent: Wednesday, April 02, 2008 8:58 AM
Subject: [urq] MB brake question


> Hi Guys,
>
> I have a small problem, I beg your pardon if this has allready been
discussed on the list.
>
> My -88 MB does OCCASIONALLY the following:
>
> last summer on my way home sitting in heavy traffic, only on hot summers
days, and even then very occasionally, at first the brake pedal started to
feel a bit firm. I had no problem with lack of brake assist though and the
pedal travel was normal.
>
> When I got out on the motorway (about 80-100 km/h), and after a few
minutes drive the pedal went almost all the way to the floor, before the
brakes worked, and at this stage there were no assist on them. I have never
had a problem with brakes locking up.
>
> This happened about 3-4 times during whole last summer, and I drove the
car to work every day.
>
> The problem ought not be with the bomb while it is quite new. I cannot
remember how many times I can press the pedal before it gets hard, from the
top of my head approx. 20-30 times.
>
> The weird things are that this happened very occasionally and only when it
was hot, after sitting in heavy traffic, never during a traffic jam.
>
> Any ideas?
>
> Cheers,
> Johan
> Helsinki, Finland
> -88 MB with NEW window winders and studded tires
> _______________________________________________
> Audifans urq mailing list
> Send posts to: mailto:urq at audifans.com
> Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
> UPG2008 planning at: http://autos.groups.yahoo.com/group/urquattro/
>
> You can help keep the audifans site running by shopping at
http://audifans.com/shop/
>