Master cylinder port confusion

[KTPhil]

I'm replacing the original master cylinder on a '71 fastback. I am discovering that there are several different port arrangements on master cylinders. Here is my car (known original since it's been in the family and I have done all the work). This is a view with it installed, from the driver's side underneath (cloth backing it for clarity):

I have a NOS master, ATE part number 03.2119-3713.3; there is no VW part number on either the box or unit. No threads on the flange, so I know it's for a T3, not a T1. Also, the box has a handwritten “SBack” which I take to be for “squareback.” Here is the same view of the new part:

And here's the right:

My problem is connecting the right lines to the right ports. Notice the two different orifice sizes. I would presume that the large orifices are for the switches (since there are two), and the small orifices are for the wheel lines (since there are three).

But if you look at my OG unit, the switches are on opposite sides, not the same side.

This means I would have to change out the brake lines, or get a different new MC.

Some other info... I know of the two types of duals: those with the single-pole switches that use an extra balance piston to actuate the switches, and the later type with a three-pole switches that lack the extra piston. I have the latter. But apparently there are at least two configurations of the latter type.

Check out these repair manual photos. Here is Bentley; this is consistent with the NOS part in that the switches are on the same side.

Here is Elfrink; it's odd in that it has one switch on the end, unlike either my OG or NOS unit. It DOES show, however, that the switches have the large orifices, and the wheels have the small orifices:

Now we get to Clymer, not my favorite source for accurate information. The first photo is not like mine at all; note the angled ports for the switches:

Such a configuration does exist, because there is an ad on the Samba for a NOS part of this type. Tt wouldn't solve my problem of port arrangement, though:

Clymer's second photo shows the switches on the same side, but the SAME size ports on both the switches and the wheel lines:

Taking all this into account, I seem to have a non-standard MC installed from the factory.

Does anyone have photos of a '71 T3 that might confirm this?

My options are to:
1) rebuild the MC I have installed
2) make up a new line for the driver front wheel line (to let it reach the other side of the MC)
3) get a different new MC. I prefer NOS German if I am installing a new unit.

Anyone got a NOS German unit that matches my car?

Anyone have info on making up an extension to my brake line? Thread size, union type, pipe diameter, etc.? I am leaning toward this solution sinc eit leaves the car and the parts unchanged. Of course, the union has to be good and tight.

Thanks!

[COFBack]

KT

Look in my gallery and previous posts. Funny that your Master Cylinder doesn't look like mine (also a '71 Fastback). Mine could be a replacement but I am the second owner and the car didn't have that many miles on it.

I ended up having Jim Adney rebuild my master. I have one of the later (or is it earlier) model masters in in my parts box but chose not to use it as I didn't feel like building the hard line.

RMS
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[BSQUARE]

[Russ Wolfe]

This is the master cylinder I installed today in my 69.

This is the OG one I took out.

In the mean time, I blew the main line between the front and rear while bleeding the brakes. so, It is tomorrow before I can get it done.
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

[Dodgy]

Just by coincidence, I was looking in the Type 1 Bentley last night and noticed a comment about the master cylinders. The large / small orifices were added to replace some sort of restriction valve. I guess similar technology was used in the Type 3.

Will have another look, but it will be Monday before I can post any more info.
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[KTPhil]

Well, until I go back and compare books, the following will add to confusion, not remove it, but here goes...

I remember reading about several changes/differences between disc/drum and early/late masters. I think there was a change to remove a check valve that kept slight pressure in the lines not needed/wanted for discs. This might have also been the function of those adapters/fittings that are in some of the early drawings.

I know this doesn't answer the issues, but I would want to understand those changes before assuming which master goes on which brake setup. If I figure it out I'll re-post.

[BSQUARE]

to alleviate some confusion- after some searching, I've figured out that this is a super beetle master cylinder.
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1968 Regatta Blue Squareback

[KTPhil]

The angle of the front inlet and the threads on the mounting holes (if that is what I am seeing) also suggest this. But you can see the port configuration is like one of the many T3 types.

The confusion continues...

[BSQUARE]

yes, the mounting holes are threaded. the inlet ports are set about 45 degrees from vertical, away from the reservoir. i found three different brands (brax, varga, and girling) of super master cylinders with the same configuration. this is most definitely NOT a type 3 master cylinder.
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1968 Regatta Blue Squareback

[jan72]

Hi, i know it's an old topic, but the problem is the same: do the lines connect to the ports with small holes and the switches connect to the ports with bigger holes on the left side?
Nevermind, got it:

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'72 Superbeetle
'72 Squareback

[Russ Wolfe]

Lines connect to the ports with the small holes.
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

[66311]

[Russ Wolfe]

Beetles were drum brake in the USA, but disc brake in Europe.
Also, the Type 1 Karmann Ghia had disc brakes starting in 1966 the USA. And dual circuits starting in 1967.
_________________
Society is like stew. If you don't keep it stirred up, you end up with a lot of scum on the top!--Edward Abbey

Gary: OK. Ima poop.

[jan72]

You don't need to rebuild a NOS pump, there are new ATE units available. Same part number 03.2119-3713.3. Still, the price is around 150$.
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'72 Superbeetle
'72 Squareback

[66311]

[Russ Wolfe]

[KTPhil]

[Ajvanloo]

Old thread, but maybe some of you are still checking it out... Anyone know what type of master cylinder this is? It came off my '73 fastback and the one I ordered is quite different. The one I ordered has 3 ports on passengers side and 2 on drivers side and 2 on top I believe. This one as you can see has all the ports on one side and on the top. Any clue?

[Bobnotch]

Judging by the lettering of the casting (below the plastic tube), I'd say it's a Varga. But it looks like a modified super beetle master cylinder, going off the above pics. Someone probably drilled out the mounting threads, and used it as a cheap replacement.
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120

[Ajvanloo]

Thanks Bob! I don't mind paying for the correct one, but first I need to figure out which one is correct. The switch on top isn't attached to anything so I figured they used it as a plug. There is also a plug on the top far right port (in first pic). I found some that are similar online. The number on the other side starts with a '0029'. I found a few trw (varga) replacements but were slightly different and started with '0025' or '0030'. If I can find the correct one I could probably match it to an ATE. I guess I'll just have to write down the correct ports and match it up with one...