Date:         Tue, 14 Oct 1997 00:20:35 -0700
Reply-To:     Rick Gordon <rickgo@HALCYON.COM>
Sender:       Vanagon mailing list <Vanagon@Gerry.SDSC.EDU>
From:         Rick Gordon <rickgo@HALCYON.COM>
Subject:      re Eurovan brake vibration
Comments: cc: Andrew Mera <am1973@MONIKA.DS.BOEING.COM>
Content-Type: text/plain; charset="us-ascii"

>My 95 Eurobago has developed a pulsation of the brake pedal
>when applied at speeds above 50 mph;  feels like something is
>out of balance between the pedal and the road.  My original
>Goodyear tires have 20k miles, cann't see any uneven wear.
>VW replaced the front brake rotors; this didn't change anything.
>
>Has anyone had a similar problem, or know the cause of such resonance?
>Thanks,
>

I've had interesting vibrations in the Volvo tires when one of the steel
belts broke. I couldn't even see it until a mechanic showed it to me - just
a slight bump - even then I was skeptical but replacing the tire fixed the
problem.
Although I don't think this is your problem I just thought I'd point out
how subtle the irregularity in the tire can be to cause significant
vibrations!

(Actually this could be the problem - if it were in the rear tires you
wouldn't feel it in the steering wheel - but when the pads made contact
with the rotors there *might* be a vibration which pushes hydraulic fluid
back - then again there are a lot of valves between the pedal and the pads
so I'm just guessing.

Other thoughts: brake pads wearing down. some pads I think have a material
that's designed to make noise/vibration before you get to the metal. If
your tires have 20K miles then your brakes do too? There's a lot of mass to
be stopping in that van and they may wear faster than normal. But you
replaced the front rotors? That almost implies the pads were wore down.
What about the rears?

Or a long shot: something wrong with the ABS? (I hope not).

-rick

Rick Gordon
Bainbridge Island, WA, USA
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rickgo@halcyon.com
http://www.halcyon.com/rickgo/
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