This summer, I started changing the brake fluid in all my cars, including my Lincoln.
I followed the same procedure I used on my Cadillacs, but when I thought I was done, the car suddenly lost all its brakes and the brake warning light came on.
I was completely baffled. After a web search (or I should’ve just read the shop manual before I started bleeding), I found the answer in a Lincoln forum.
Turns out, you can’t bleed these brakes with a vacuum bleeder, according to the manual.
The correct way to do it is to pressure bleed it from the master cylinder.
There’s a metering valve underneath the car that you need to release if you run into problems.
The shop manual says you need a special tool, but a simple screwdriver worked just as well. Follow the brake lines to find the valve right in the center underneath the engine at a crossbar. The pin is underneath a rubber gasket. Pull it out and bleed the brakes.
After I did that, the brakes were working perfectly again. Interestingly, earlier years of the Mark III had a different valve that even needed calibration and was much more complicated. I’m glad I have a 71, which doesn’t have that system.

That's the valve you have to open

Tags:1971 Lincoln Continental Mark III, Repair, 1971, Brake Fluid, Bleeding, Lincoln Mark III Repair Tip