Bleeding the Brakes on My ’71 Lincoln: What I Wish I’d Known First

This summer I refreshed the brake fluid in all my cars — including my 1971 Lincoln Mark III. I started with the method that always works on my Cadillacs: vacuum-bleeding each wheel until the fluid runs clear. Everything went fine… until it didn’t.
After bleeding the Lincoln lost all braking power and the brake warning light came on. After some head-scratching and a dive into the shop manual and forum threads, I learned the key detail I’d missed.
The Problem: Vacuum Bleeding Doesn’t Work on These Cars
After some head-scratching (and finally checking both the shop manual and a Lincoln forum), I learned something that would have saved me a lot of trouble:
You cannot bleed a 1971 Lincoln using a vacuum bleeder.
According to the factory manual, these cars must be pressure-bled from the master cylinder. If you vacuum-bleed the system, the front brake metering valve can trip. When it does, it shuts off fluid flow—instantly giving you that “no brakes at all” moment I experienced.
How to Reset the Metering Valve
Luckily, resetting the valve is quick and straightforward.
The metering valve is mounted underneath the front of the car at the crossmember, roughly centered under the engine.
On the ’71 Lincoln you must pull the pin out and hold it out. That opens the metering valve so fluid can flow — and while it’s held out, you can even vacuum-bleed the system safely.
The manual mentions a special tool for this, but in practice a small screwdriver or a pair of pliers does the job. The crucial point is to hold the pin open during bleeding so the valve stays open for continuous fluid flow. If the pin is not held out, the valve will block flow and you can end up with the “no brakes” moment I experienced.
Where to find it and how to do it

1. Crawl under the front of the car and follow the brake lines to the center at the front crossmember (underneath the engine).
2. Look for the metering valve — you’ll see a small rubber boot covering the pin.
3. Pull the boot back, grab the pin (a screwdriver or pliers works), and pull the pin out.
4. Hold it out while you vacuum-bleed each wheel (or clamp/pin it so it stays out).
5. When bleeding is complete and no air remains, reinstall the pin and boot, then test the brakes carefully.

Tools & tips

• Special tool: listed in the shop manual, but not strictly necessary.
• Practical substitutes: small screwdriver, long-nose pliers, or a hooked tool to pull and hold the pin.
• Hold the pin open the whole time you’re bleeding (don’t just press it).
• If unsure, perform a final pressure-bleed from the master cylinder or get a pro to confirm.

Safety first
Brakes are critical. After bleeding, always check pedal firmness and perform a low-speed test in a safe area before driving normally. If the pedal feels spongy, or you’re not confident in the job, stop and have a professional inspect the system.
Final note
Earlier Mark III models used a more complicated valve that required calibration. I’m glad the ’71’s simpler pull-out pin made this fix straightforward — once I knew what to do. One pulled pin and a proper bleed later, the brakes came back to life.

That's the valve you have to open

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