Back when we had the good German parts, the rear cylinders had springs in
the bore to keep the pistons engaged a bit. This made for a nice tight firm
pedal as long as the adjustment was good.
Nowadays, not sure if any of the replacements have the springs in them.
 I would buy the best quality possible from our online vendors rather than
chance a FLAPS part of unknown origin. Guys like Ken at Vanagin or  VanVolks
Cafe work on these things and DO know the drill.
Daryl of AA Transaxle
(425) 788-4070
aatransaxle.com
86 Syncro Westy
Zetec in the trunk
----- Original Message -----
From: "Edward Maglott" <emaglott@BUNCOMBE.MAIN.NC.US>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, March 28, 2009 9:16 AM
Subject: Re: another brake saga...aha!

>I got out my the old wheel cylinder that was not leaking.  I had
> thrown away the one that was leaking.  The old one appears to be OEM,
> may be original.  The difference between this one and the FLAPS one I
> bought is that the OEM one has little clips in the slot that engages
> the shoe.  This holds the piston out against the shoe.  Re-bled that
> wheel cylinder, adjusted the brake shoes, now I've got a nice firm
> pedal that doesn't become soft after a few minutes as that piston
> drifts back into the cylinder. I still have to take a test drive so
> success is tentative.
>
> Tips I learned in this process so far:  You can change the cylinder
> without taking the shoes off.  Adjust the brake shoe adjuster all the
> way out.  Remove the bleeder from the cylinder, disconnect brake
> line, unbolt the cylinder and it comes out.  When adjusting the rear
> brakes, I raise both rear wheels and take off the wheels.  Adjust,
> pump brakes, adjust, pump brakes, etc.  Then I start the engine and
> put it in gear so the rear hubs spin.  Step on brakes a few
> times.  Put in reverse, repeat.  I think this helps center the shoes
> better because in regular use the shoes are pressing against rotating
> drums, not ones that are still.  I then turn off the engine and can
> usually adjust the shoes out a little further.
>
> Edward
>
> At 10:07 AM 3/28/2009, Edward Maglott wrote:
>>David,
>>I'm gong to look at that.  These are FLAPS wheel cylinders, so I am
>>suspicious of their quality.  I talked to the automotive instructors
>>at the community college I work at.  They've seen a lot but were
>>puzzled by these symptoms, except for the possibility that the
>>cylinder was defective.  They mentioned the spring(s) inside.  I'm
>>going to pull out the old leaking one and take it apart and see
>>what's inside.
>>
>>Edward
>>
>>At 09:17 AM 3/28/2009, David Milo wrote:
>>>Now that I'm thinking about this, I'm fairly certain that the last
>>>pair of rear wheel cylinders I installed had coil springs inside to
>>>keep the pistons out; the rubber boots kept the pistons from falling
>>>out completely.
>>>
>>>Does you old cylinder have the springs inside?
>>>
>>>Dave
>>>
>>>On Sat, Mar 28, 2009 at 8:46 AM, Edward Maglott
>>><<mailto:emaglott@buncombe.main.nc.us>emaglott@buncombe.main.nc.us>
>>>wrote:
>>>I can add some additional info to my saga now.  (I have the
>>>previously mentioned videos posted
>>>at:
>>><http://www.youtube.com/user/emaglott>http://www.youtube.com/user/emaglott
>>>watch the piston on the
>>>right side.)
>>>I hooked up my pressure bleeder and put about 10psi on the
>>>system.  The piston stayed out against the shoe.  when I open the
>>>bleeder valve, the piston moves back into the cylinder away from the
>>>shoe. Close the bleeder, it moves back out.  I was still suspicious
>>>of the boot so I pulled it back, sort of inside out on the
>>>piston.  Then the piston stayed out when I opened the bleeder valve
>>>on the cylinder.  Then I took off the pressure bleeder and it still
>>>stayed out, even when I opened the bleeder valve.  When I put the
>>>boot back in place, it went back to its old habit of pulling back
>>>into the cylinder.  So I'm pretty sure it has something to do with
>>>the dust boot (ha ha).  I'm gong to take off the cylinder and put my
>>>old one back on (the one that wasn't leaking yet) and see if I get my
>>>nice firm pedal back.
>>>
>>>Edward
>>>
>>>
>>>
>>>
>>><Snip>