Date: Wed, 14 May 2008 00:26:15 -0700
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Brake pedal fades to floor at stops
In-Reply-To: <6543F3D7-D99B-47D2-9588-0A5B5A00C2CC@mac.com>
Content-Type: text/plain; charset="us-ascii"
That's true , if it was 'just air the lines" ( which does not happen unless
something is worn out, or the brake fluid is 10 + years old ) - yes, you can
usually pump the pedal and get some pedal, if there's air in the
lines,usually."
Air does not get in the brake lines or fluid for any reason other than
something is worn out, or numerous something's.
Just plan ole 'not enough brake fluid in the Reseevorir
It's not that likely it just 'needs the fluid topped up'.......though that
is possible. Brake fluid does not just 'dissapear.'
The level goes down very slowlyh, like a quarter an inch in a few months, as
the front brake pads wear.
Wearing front pads is the onlyh 'normal reason' the brake fluid level goes
down.
It can take months, ever years for it to go down for this reason, unlees the
brakes are used insanelyh hard and frequently.
All other reasons for the BF level going down in the Res - is due to worn
parts and never chaging/bleeding the brake fluid.
Brake fluid absorbs moisture out of the air - it's supposed to.....
Just sitting there, not driving or using the van, brake fluid absorbs water
out the air. The affect is very slow.........normal and safe brake fluid (
which means bleeding them to accomplish chagine it ) .....is done every 2
years.
Some vans NEVER get this.
EVentuallyh........breake fluid turns to dirty black thin water.
This also ruins all components in the hydraulic parts of the entire breake
system.
On the other hand, ......religeously changing the brake fluid every two
years........and monitoring friction material wear, and using the brakes
nicelyh and appropriate ........the brake system can last very, very well.
With frictioin material wear being the main thing - like tire tread
wearing.........as you use it, it has to wear, designed to, no big deal.
The hydraulics part however........needs the maintanence of changing brake
fluid every two years.
It takes less than an hour to change and bleed all the brake fluid in the
entire brake system- even less than that.
The one part hydraulic part that can leak first, ( and if fluid is changed ,
they can last years if good german ones ) are the rear wheel cylinders.
Their life is 2 to 5/6 years or so.
Master Cylinder life, with brake fluid changes is ........darn long, 10+
years.
If no BF changes..........5 years only,even.
And MC that's original , like 16 + years old, and there have not been brake
fluid changes ........was worn out 8 years ago, or before that even.
It would be like never bathing or showering, for years, never once......for
years........that's what never changing BF would be like.
You can imagine how crudy/unhealthy that would be, for a person's body.
I'm only exaggerating ........a bunch, but hope you get the idea.
In all cases, if resting your foot on the brake pedal makes it sink slowly
.........it's usually indiaes a tired master cylinder.
Or more.
Since this pedal thing is happening..........
What is really indicated is to .......
Check the bf level in the reservoir, immediately !
Fill if low.
I wouldn't be surprised if it's low, very dirty, and like black water.
And/or there is barely any fluid in there.
I've seen many a master cylinder, in a car used daily.......that had one
eight inch of filty black was brake fluid once- dirty black water.
There is a 3 % chance, likely assuming/guessing the van was 'just driven' in
the brake department, for years ev......en..
There is 2.9 % chance bleeding the brakes will restore a firm , higher
pedal.
Read on if you got this far and are learning something.
Bleeding the brakes is also a diagnostic procedure - you bleed the brakes -
to see if the master cylinder is capable even, of pushing brake fluid, in
both circuits.
This is 'why' .....I prefer using a 'pump pedal ' brake fluid bleeding
method , as opposed to a pressure bleeding system.
Feeling how the MC feels while you bleed it with a pedal method......tells
if you it's pushing fluid, and you can also observe if it pumps in air, in
your clear tube.....and an MC most definitely can pump in air if it's worn.
It takes doing this method numerous times to develop a feel for what it
should feel like. When it's right if feels right too.
There can also be a leak between the two circuits in the MC - same symptom,
low and/or, sinking pedal.
Also .......there must be a front wheels off, and rear drums off 'real'
brake inspection, in this case, looking for leaky rear wheel cylinders,
front calipers, hoses etc.
Perhaps those areas were just fixed last year...........
It could also just just be the tip of the iceberg, this siking/low pedal.
Be Careful !
It is folly to replace a master cylinder with out having some idea, at
least, in the brakes at the wheels.
If done last year, fine, you might let that slide. If you have no idea, it
is imperative to do a FULL wheels and drums off brake inspection , in all
wheels.
Also, consider the Brake Booster - they last very well, never getting
replaced on some vanagons, even after many years. But it is a major
component, they do wear or fail..........and this one could be full of brake
fluid from the likel very worn master cylinder.
At a place like Midas Muffler, or a good automotive repair shop.......when
it's really bad in the whole system sometimes a shop like that can say, and
mostly honestly too, that you need 'everything' to the tune of over a
Thousand bucks, easily. I break the job down into what's worst , and
replace the worst stuff first, irestoring the entire system back to health,
in steps, if safe and reasonable to do so.
I hope......I hope all is well, or half decent at least in the brakes at the
wheels.
There are ...........roughly 30+ components of the brake system on a
vanagon, almost all of which wear , some fairly regularity - some more
slowly.
There is also a brake pressure limiting valve under the front of the van,
right side. Never had to replace one , on hundreds of vanagons.....
There is a chance it's 'just a master cylinder.' If bleeding only restores
the firm-ish pedal, it is likely just a temporary improvement.
Good luck !
Scott
www.turbovans.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Kim Brennan
Sent: Tuesday, May 13, 2008 8:44 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Brake pedal fades to floor at stops
No. Air in the lines would show up as having no braking power unless
you pumped the brake pedal.
This is more indicative of a failing master cylinder.
On May 13, 2008, at 11:03 PM, Slloth wrote:
> I'm pretty sure this isn't normal. But I noticed today when I am at a
> stop and I have my foot resting on the brake pedal it slowly fades
> till
> the pedal hits the floor. Is this caused by air in the lines?
>
> --
> '84 Westfalia, 1.9L
> '73 FJ40, 2F
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