The two bleeders Options

[emerygt350]

I just popped on my newly remastered rear brake calipers from PMB and was wondering if there was a point to the lower bleeder? I only ever bothered with the top bleeder before but now that it's bone dry I was wondering if that might be why the second bleeder exists? I will be bleeding the brakes tomorrow morning.

[technicalninja]

Disagree. You have to look at this from a manufacturing perspective.

Take a look at the inboard side casting, it is symmetric. The casting is not handed until the machining operations are done for the handbrake.

Having lived and worked in a manufacturing environment, my best educated guess is that the piston bore and the bleed screws were machined before the park brake bore.

This allows the casting to remain unhanded for easier inventory management. Since ATE was suppling these calipers to other OEMs there would be an advantage to not having handed calipers until as late in the machining process as possible.

In this day and age, no one would do two matching operations and provide two bleed screws. It amounts to giving away money. But back in the 70s before computer inventory management and just in time delivery of parts there would be a great deal of value in minimizing handed parts.

I'm in agreement with this. They made one casting each for the inside parts of both front and rear calipers to reduce tooling costs.

Now, with the information that Davep provided regarding servicing, this should have been included with ALL caliper designs.
Not just Porsche ones!

My Dad once had a 964 S4 that had been heavily modified. It had the Porsche "cup" suspension on it and the "Big Red" brakes. Whoever installed these did not get a matching "kit" as it had two front left calipers and those puppies only had one bleeder.
The right-side bleeder was pointing down which made it impossible to bleed unless you knocked it loose, stuck a piece of wood between the pads. and held the caliper bleeder up for the bleeding process.
That worked fine but it was a bit of a PIA to do.
Had they had the dual bleeder set up it wouldn't have been a problem...