30,000 Miles and a Brake Surprise

I have owned my 1967 Eldorado since 2009. I bought it with around 27,000 miles on the clock, and I have always pampered it because I wanted to keep the mileage low.
The Odometer Turns Over
Today, 17 years later, the odometer rolled over to 30,000 miles, which I did not enjoy very much. But these cars need to be driven.
Fresh Fluid, No Pedal
The brake fluid was due for a change as well, so I used my vacuum bleeder. When I finished and wanted to check the brakes, the pedal went all the way down to the floor.
The Valve That Tripped
My Eldorado has the optional front disc brakes, and with them comes a metering/distribution valve that triggered during bleeding, so the bleeding did not work. A look into the shop manual revealed that I should have secured the valve before I started. There is a special GM tool for this, which you screw in instead of the brake light warning switch before bleeding.
I solved the problem by pushing in a small prong underneath the valve and bled the brakes again.

When using a vacuum bleeder on a 1967 Cadillac Eldorado, you must manually hold the front metering valve pin pulled out while bleeding the front calipers, and use Teflon tape or grease on the bleeder threads so false air bubbles don't trick you.

1. Prep the Metering Valve (Front Brakes Only)

• Why: A vacuum bleeder only pulls ~10–15 inHg of suction, which is not enough pressure to overcome the internal spring inside the 1967 metering valve. Without holding it open, almost no fluid will draw through the front disc calipers.
• Pull and hold: Peel back the small rubber dust boot, carefully grip the stem with needle-nose pliers (avoid gouging or nicking the smooth shaft so you don't tear the internal O-ring seal), and pull the pin outward.
• Keep it held: Hold the pin outward—or slip a small slotted spacer/clip behind the pin's head to keep it pulled out—while drawing fluid through the front calipers with your vacuum bleeder.
• Do not force it inward: If the pin bottoms out immediately when you try to push it, that confirms it is the pull-out style; pushing harder will only damage the internal valve seat.
• Test if vacuum still pulls fluid: Some mechanics note that low-vacuum bleeders (~10–15 inHg) do not always trip the valve shut in the first place. If fluid flows freely through the front calipers without touching the pin, you do not need to force it at all.

2. Seal the Bleeder Screw Threads
• Why: Vacuum bleeders suck air around loose bleeder screw threads, creating endless tiny bubbles in your clear hose even after all air is out of the brake lines.
• What to do: Remove each bleeder screw one at a time, wrap 2–3 turns of Teflon plumber's tape around the threads (keeping it clear of the bottom tip/hole), or dab heavy grease around the base of the screw before reinstalling.

3. Step-by-Step Vacuum Bleeding Sequence
1 Top off the master cylinder with fresh DOT 3 fluid and leave the cap resting loosely on top so vacuum can form in the lines without collapsing the rubber diaphragm.
2 Start at the Right Rear (then Left Rear, Right Front, Left Front). (Note: You do not need to touch the metering valve for the rear drums).
3 Pump up vacuum: Attach the vacuum bleeder hose to the bleeder nipple and pump the hand gun to 10–15 inHg of vacuum.
4 Crack the bleeder open: Open the bleeder screw 1/4 to 1/2 turn. Watch fluid flow into the catch cup while continuing to pump the hand vacuum to keep suction steady.
5 Close while under vacuum: Once you see clean, bubble-free fluid (or a solid stream without large air pockets), tighten the bleeder screw BEFORE releasing the vacuum on the gun.
6 Check master cylinder: Refill the master cylinder reservoir after every single wheel—vacuum bleeders pull fluid quickly and can run a reservoir dry in seconds.

4. Final Pedal Check
• Because vacuum bleeding draws fluid gently, small micro-bubbles can occasionally cling inside the calipers. After finishing all four wheels, pump the brake pedal with the engine off—if it feels slightly spongy, finish with two quick manual pedal-pump cycles per front caliper to purge any stubborn trapped air.

Just rolled over to 30k

It rolled over when I returned from this show


Bleeding brakes

The pin underneath the distribution valve you have to pull out when bleeding the front brakes on a disc brake car with a vacuum bleeder.

Tags:Disc Brakes, 1967 Cadillac Eldorado Repair Tip, 1967 Eldorado, Bleeding, Vacuum Bleeding, Metering Valve, Distribution Valve