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Re: Pulsating Brake Pedal

To: "Patrick J. Horne" <horne@cs.utexas.edu>
Subject: Re: Pulsating Brake Pedal
From: RWM <RWM@rwmann.com>
Date: Mon, 07 Oct 2002 14:24:55 -0400
Pat,

Good suggestions.  Drums are true.  Rotation speed-related pulsations and
jacking appear to have been due to periodic drag created by the friction surface
pieces and debris floating between drum, backing plate and shoe backings.  Quite
a mess.  Failed friction material was sort of a green/gray color.

The appearance of "fluid loss" at the reservoir was caused by loss of the
complete lining depth at left rear, filling the wheel cylinder.

Fluid back-pumping in the master reservoir for the rear system is still under
investigation.  

- Bob

"Patrick J. Horne" wrote:
> 
> Pulsations generally mean that either a rotor is not of constant thickness
> and when the pads hit the high spot they push back, causing the petal to
> move up. Same for drum breaks if the drum is out of round. I suspect that
> the dragging brake due to the de-bonding fof the friction material heated
> up the drum enough so that when the brakes were applied that it distorted
> the brake drum from round to oval. I hope there is enough material left to
> turn the drum round again!
> 
> I had a similar problem with an old VW type 3. The liking on one rear
> wheel got oil soaked and when I had to make an emergency stop it just
> slowed down. I pulled up on the handbrake , which helped a bit, avoiding
> an accident. After that stop the brakes pulsated until I had the drum
> turned and replaced the soaked linings.
> 
> Peace,
> Pat
> 
> - Support Habitat for Humanity, A "hand up", not a "hand out" -
> 
> Pat Horne, Network Manager, Shop Supervisor/Future planner, CS Dept,
> University of Texas, 1 University Station C0500,Austin, Tx. 78712-1188 USA
> voice (512)471-9730, fax (512)471-8885, horne@cs.utexas.edu
> 
> On Sun, 6 Oct 2002 Beamonk@aol.com wrote:
> 
> > I kinda have the same problem, although I feel it is from my zx mags not
> > being perfectly on center. I have the larger lug nuts which hold torque, but
> > get some lateral shake from the rear under braking.
> > John
> >
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