Why is it that some parts on this car, list a Part Number in the PIM, but they do not look like the part as shown? Even better the stock replacement parts match neither sketch or what is on this car.
PIM Manual Sec. 5 Page 100 sends me to Page 112 (for Manual Disc Brakes). I have two hold down spring clips, clipping into the sides and the PIM shows one spring clip clipping into the front and rear.

I suppose they grabbed whatever one was on the assembly cart, the day it went through that section of the factory.

So much for identical replacement, I will go with a rebuild kit and see if I can find the correct cap seal.
No, the original one I have is not leaking a drop (probably should just leave it alone).

Car has all original brake components - less front pads and rear shoes.

This car will never be a 100 point car, nor is that my goal here. But if a car does not have the exact original parts, how could it be judged at 100 pts.

 

If you still need help with the correct original parts, I can help
I have the experience and parts also.
By the way for 1971 the correct master for disc brake automatic cars is code BE

 

They did not randomly install parts on the assembly line. Olds had to warranty and service these cars when new. Configuration management problems like that would have caused all sorts of problems in the service and parts networks. The reality is that the engineering drawings in the PIM were all hand drawn on drafting boards. Engineers and drafters are lazy and we reuse as much as possible, especially as opposed to having to draw new by hand. There are a LOT of examples in the PIM where the drawings reused prior year artwork that did not match the new parts. So long as the part numbers were correct, there was no need to change the image. FYI, the technology then was called wash-off mylars. The original print would be reproduced on a mylar using special water soluble ink. The drafter could erase portions of the mylar drawing using a special sponge with a water reservoir and an electric eraser. We then would ink the changes to reflect the needs of the new drawing. If the older parts of the drawing were close enough, send it. Don't lose a lot of sleep over stuff like this. Go by the part number. Also keep in mind that those part numbers evolved or were superseded as time went by, so even an NOS part you buy today that matches the original part number may appear to be different based on the part number history. That's a whole separate set of books, by the way.

 

The master cylinder you described with 2 clips sounds correct for a 71/72 W-30 with manual disk brakes. As you stated the drawing in the PIM manual is not correct for 71. Going from memory the code is ST for the manual disk master cylinder. RocketDevo noted BE is correct for power disk brakes.

Don W

 

After multiple searches, I finally found a new master cylinder that matches the casting of the original on this car ('71 manual disk), I have no idea where it was manufactured. Purchased from YearOne (NG1124 (and I will hold on to the original as I have with every Item I'm replacing)).
The casting number on the original looks like 6488105-1 and is on the bottom -



Reading the post from Joe, it seems strange and different from the very large Engineering firm I work for (that builds aerospace products and other goodies) Our computer models and drawings of today, started out on paper and mylar over 100 years ago (here in the PNW). My usage of those older drawings and mylars, only date back to the 1950's for products and some that are still in the air today, every revision made is and still is recorded and in vaults (now servers).
I do understand the processes required in automotive with such quick turns in generational changes.