[T3] Master Brake Cylinder, cont'd...

Jim Adney jadney at vwtype3.org
Fri Nov 17 22:42:10 PST 2017

On 18 Nov 2017 at 0:03, J. Jonik wrote:

> Found one spare Master Cylinder with the same configuration of brake
> lines and electrical ports.   Number embossed on the body is "61"...or
> "19"...depending on how you look at it.   No other numbers visible.  
> Does that number say that it's for a '71 specifically?

It's a 19, which is the bore diameter (3/4") to the nearest 
millimeter. All Type 3 MCs, except for a few 3/16" in very early 
ones, came with 3/4" bore MCs.  

> This spare wasn't drippy, had rusty end under the rubber boot, and had
> two electrical things screwed lightly in...hand loose.  The holes for
> the electrical things looked no different from the brake fluid line
> holes. 

Look at the bottom of the port, the small drilling that goes into the 
center of the MC. That's the part that's dramatically different.

> Then, taking it apart and re-assembling looks tricky...out of my
> league at least because I have nothing to hone the inside (if needed),
> and no cone tool to slip on new rubber rings...IF I can even find a
> re-assembly kit. 

No special assembly tools needed, if you just want to inspect the 
bore and rubber parts. A hone is cheap. There's a lot to be learned 
by just looking inside. Up to now you seem to be looking at this as a 
black box and thinking "What could possibly go wrong?" Take it apart 
and find out.

> I'm thinking to just do the job of taking a chance and put in this
> rusty (on the outside) master cylinder into the car and see what
> happens.   OR...are re-built or new ones available?   I couldn't send
> my existing MC to anywhere for core exchange or anything because then
> I'd have no car for however long it takes. 

I rebuild more MCs and calipers than anything else. You could send 
the one in your hands to me. It might not be rebuildable, but you'd 
only be out the shipping.

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

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