Date: Mon, 13 Mar 2000 23:00:47 -0800
Reply-To: Coby Smolens <cobys@WELL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Coby Smolens <cobys@WELL.COM>
Subject: Re: Mushy brake pedal question
In-Reply-To: <11A2A5877BEFD111998900A0C9C74AD83D6ED9@info_hq.infogenesis.com>
Content-Type: multipart/alternative;
RE: Mushy brake pedal questionIf they are really pumping up to a normal,
firm pedal after one stroke I'd say adjustment of the rear shoes is the most
likely culprit, but perhaps not in the way you might expect -- to whit:
Another thing to consider is drum size. You should get them measured -
maximum allowable inside diameter is 253.5, this considers the final allowed
machined thickness after turning (253mm) plus .5mm wear after that. This
symptom is typical of drums that are oversized, or even just approaching the
limit. Anything over 253mm is time to start considering new drums. Add the
fact that those brake shoes are nearing their limit, and you don't have to
look any farther into the hydraulic side of the system for the source of
your squish.
Used to be you could replace the brake shoes with oversized shoes - they
used to be available from the dealer in two oversizes, and you could just
have the brake drum turned to match the first or second oversize. This way
there was always the correct relationship between the arc of the shoe and
the arc of the drum. Unfortunately, oversized shoes are a thing of the past
(as far as I know). So now, the inner arc of the drum gets bigger while the
arc of the shoe gets smaller, to the point where the self adjusters can't
compensate anymore.
Or maybe someone installed the rear adjusters on the wrong sides? Wouldn't
be the first time. Although if that's the case, you can usually get the
things adjusted - the adjustment just doesn't last long, as they work in
reverse, loosening the adjustment with each push of the pedal.
Having said all that, I have to admit the possibility still exists that some
weird hydraulic event MIGHT be occurring in the master cylinder, but I doubt
it - especially if the first premise listed above holds true.
Good luck!
Coby
Valley Wagonworks
"Intimately acquainted with VW Vans since 1959"
Volkswagen Bus, Vanagon, Westfalia and Eurovan
Repair and Service Specialists
1535 Sir Francis Drake Blvd., San Anselmo, CA 94933
Voice:(415) 457-5628
Fax: (415) 457-0967
http://wagonworks.com
mailto:contact@wagonworks.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf Of
BRENT CHRISTENSEN
Sent: Monday, March 13, 2000 2:50 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Mushy brake pedal question
Thanks Stuart:
>Brent, pull up the parking brake and see if you get a firm pedal on the
>first pump. If so, your rear brakes are out of adjustment. If not,
>you could try replacing all the hoses.
Yep - this helps, so I did adjust the rears. Problem is, the pedal is
still mushy and the rear brakes are so tight they are now dragging. Bulging
hoses would not "pump up" would they? I would think that they would swell
and then shrink with each successive pedal pump. The symptom I am getting
is that the brakes will pressurize after the first pump.
I am wondering if it might be the master cylinder...??? If the seals were
bad, it would act like this, right?
>Did you put the calipers on the correct sides? It may be impossible to
>switch them on the Vanagon, but be sure the bleed nipple is at the top
>of the caliper or you will always have trapped air.
I only do one side at a time for exactly this sort of reason! :-) Even
if they were on the wrong side, I bleed the brakes with an EZBleed and
attach the drain hose to ball-type check valve submersed in brake fluid.
Brent Christensen
Manager Strategic Programs
InfoGenesis
www.infogenesis.com
(805) 681-8600 xt. 414
-----Original Message-----
From: Stuart MacMillan [mailto:stuart@cobaltgroup.com]
Sent: Monday, March 13, 2000 2:46 PM
To: BRENT CHRISTENSEN
Cc: vanagon@GERRY.VANAGON.COM
Subject: Re: Mushy brake pedal question
At 4-6mm it is time to replace your rears anyway. No special tools are
needed, just patience. Do one side at a time so you have the other for
reference. Have the drum turned too if there is any scoring or a ridge
on the outer edge.
> BRENT CHRISTENSEN wrote:
>
> Well, my battle against the mushy brake pedal continues...
>
> After completing a *complete* front brake job (new rotors,
> semi-metallic pads, caliper rebuild), I adjusted up the rear brakes in
> an attempt to get rid of excess pedal travel. The pedal feels
> better, but it still improves after pumping once before stopping.
> Unfortunately, the car is now pulling a bit to one side, and after my
> 12 mi commute this AM, I noticed that both drums were HOT. Guess I
> tightened them up too much.
>
> How the heck am I going to get the pedal to feel better??? I have
> bled the system to death (In fact I used an EZ-Bleed and ran about 1
> qt of fluid through the system.) Even used the "wife method" with no
> sign of air in the system. No matter what I do, the pedal still
> always seems mushy on the first pump, then stiffens up to where it
> feels it should be.
>
> BTW, the rear linings have about 4-6 mm left, but are a tad glazed (I
> didn't have time to change the linings) - also, will a normal brake
> tool from a FLAPS work on the Vanagon drum brakes (you know, the one
> with the spring stretcher on once side and the spring
> depresser/rotater on the other side)
>
> Any suggestions?
>
> Brent Christensen
> '89 GL Syncro Westy
> Santa Barbara, CA
>
--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext. 8208
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