Ok, last night I disassembled my original '66 manual disc brake "jelly jar" master cylinder. I have a '66 shop manual, which shows how everything is put together. Figure 33 on page 2-32 shows the valve, spring, primary cup, piston, secondary cup and snap ring. I also had two small black washers that were in front of the valve. The diagram doesn't show them. A diagram on the previous page shows one such washer and calls it a valve seat. So what is correct. Should there be one valve seat, two valve seats or no valve seat. Thanks.