[T3] Single Circut Master Cyl and wheel cyl kits? Or parts to assemble?

[Jim Adney]

I've been sitting on this post, meaning to thank Soren for it. 
There's a LOT of good info here and it's one of those places where 
there's lots of confusion, and Soren laid much of it out very nicely.

A couple of comments: 

I've never seen a problem with the rubber in NOS kits or cylinders, 
but I understand that the metal bores can sometimes rust in storage, 
so I always check those before I sell or use them. The cup in Soren's 
photo looks like a very typical, very used, rubber cup. I never heard 
of any "factory" rebuilt ATe or FAG parts, but lots of places, 
including me, rebuild these.  

The master cylinder dia is not stamped on the MC, it's a raised 
casting mark, converted to metric and rounded to the ~nearest mm. 
There are also mold numbers, which can be confusing, but those are 
smaller.

Thanks for the info, Soren. I've use it to add to, and correct, the 
spread sheet I made for brake items.

Jim

On 7 Feb 2013 at 18:46, Soren Jacobsen wrote:

> The size of your master cylinder depends on what kind of car you have.
>  1965 Variants used 20.64mm (13/16") master cylinders (same as was
> used on all T3s through 1963), while 1965 Notchbacks/T34s used 19.05mm
> (3/4") master cylinders.  If you have a Notchback/T34, the rebuild kit
> is 311 698 181.  If you have a Variant, the rebuild kit is 311698191A
> (ATe 3.0370-0220.2).  I've got a 65 Variant myself, and I recently
> bought an NOS (or factory rebuilt?) master cylinder for it. 
> Predictably, the primary cup was rotten, as you can see here:
> http://blef.org/vw/t3/20mmMCrottencup.jpg  The primary cup is easily
> obtained, but I've yet to find a source (other than NOS kits, which,
> as you note, are a bit suspect) for the secondary seal.  For a 20mm
> master cylinder, you can get the primary cup from NAPA as part number
> UP12400.  With all that said, you really should check and see what
> size master cylinder is installed in your car.  After all these years,
> it's not at all unlikely that the ma ster cylinder has been replaced at
> some point, and who knows what size was installed by whomever last
> worked on the car.  Most of the master cylinders should have a 19 or
> 20 stamped on them to help you identify the master cylinder without
> removing it from the car. 
> 
> For front wheel cylinders, a 1965 T3 should have 22.2mm (7/8")
> cylinders, which you can find at NAPA as part number UP3023.  With the
> rear cylinders, again, it depends on what type of car you've got.  A
> Variant should have 23.8mm (15/16") rear cylinders, while a
> Notchback/T34 should have 22.2mm (7/8") cylinders.  The 23.8mm
> cylinder cups are available as NAPA UP3535.  Once again, I wouldn't be
> all that surprised if the rear wheel cylinders had been replaced with
> the wrong size, so I'd suggest measuring the rear cylinders before
> going out to buy parts. 
> 
> If you feel like buying all new parts, the rear cylinders for a 65
> Variant are, luckily, shared with Super Beetles (fronts for them), so
> you ought to be able to find 361611067A at any reputable VW parts
> supplier.  I'm pretty sure the 22.2mm rear cylinders are easy to come
> by as well, but I've never looked. 
> 
> Soren

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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