1991 Lincoln Mark Vii BRAKE ISSUE


Pulling into the driveway I lost all brakes, pedal went hard. So replaced pads, rotors, calipers, bearings, fluid is up where it should be and guess what....pedal is still hard. Any help here with what might be the problem???



Theresa, these have a very common hydraulic pressure pod failure (block ball looking thing). I'll have to do some research but if the pod fails, I believe you lose all power assist and get a stiff pedal (no power brakes type feeling).

Sound about right?


El Presidente
Staff member
Paid Member
You need to have the system checked with a diagnostic scanner such as the Star II tester. It is likely a malfunction in the accumulator or hydraulic pump, part of the ABS system.


The hydraulic pump maintains a pressure between 14,000 kPa (2030 psi) and 18,000 kPa (2610 psi) in the accumulator and is connected by a high-pressure hose to the booster chamber portion of the hydraulic actuation assembly and a control valve. When the brakes are applied, a scissor-lever mechanism activates the control valve and a pressure, proportional to the pedal travel, enters the booster chamber portion of the hydraulic actuation assembly. This pressure is transmitted through the normally open solenoid valve through the proportioning valve to the rear brakes. The same pressure moves the booster piston against the master cylinder piston, shutting off the central valves in the master cylinder. This applies pressure to the front wheels through the two front, normally open, solenoid valves.

The electronic controller monitors the electromechanical components of the system. Malfunction of the anti-lock brake system will cause the electronic controller to shut off or inhibit the anti-lock feature in the brake system. However, normal power assisted braking remains. Malfunctions are indicated by one or two warning indicators inside the vehicle.

Loss of hydraulic fluid or power boost pressure will inhibit the anti-lock brake system.

The 4-wheel anti-lock brake system is self-monitoring. When the vehicle ignition switch is placed in the RUN position, the electronic controller will perform a preliminary self check on the anti-lock electrical system indicated by a three to four second illumination of the amber Check Anti-Lock Brakes indicator in the instrument cluster. It is possible that both the CHECK ANTI-LOCK BRAKE and BRAKE warning indicators will stay lit for up to 60 seconds after the ignition is placed in the RUN position, while the pump runs to fully charge the accumulator. During vehicle operation, including normal and anti-lock braking, the electronic controller monitors all electrical anti-lock functions and some hydraulic operations.

In most malfunctions in the anti-lock brake system, the amber "CHECK ANTI-LOCK BRAKES" and/or "BRAKE" indicator will be illuminated. The sequence of illumination of these warning indicators combined with the symptoms can determine the appropriate diagnostic tests to perform. However, most malfunctions are recorded as a coded number in the controller memory and pinpoint the component needing service.

Have you had any "CHECK ANTI-LOCK BRAKES" and/or "BRAKE" indicator warnings?


Where might I find one of these "pods", I do think that is what the problem is. Also thank you for all the info you have already given me.....:)


I had this same issue with my 1989 Mark LSC, I replaced the ABS system with a Mustang booster and master cylinder. The conversion works great and is easy to do.


I had the same problem with ATE Teves II pump in 1987 Tunderbird Turbo Coupe (the same pump as in Mark VII and Fox-Continentals) and it turned out it just needed new pump relay. This article is very helpful to diagnose problems with these units: http://www.turbotbird.com/techinfo/TEVES II ELECTRO-HYDRAULIC BRAKING SYSTEM 87-88 TCs.htm

Try this first:
"Locate the pump relay in the plastic housing under the vacuum tree. It should be the front relay, having GY/Y, T/Y, GY/R, and PK/LB wires going to the relay socket. Remove the relay from the plastic housing, and remove the relay from its socket. Use a heavy gauge jumper wire to jumper the T/Y and GY/R wires in the socket. The pump motor should run. Do not run the pump for more than 10 seconds!"

If brake pedal operates normally after that (you will be able to depress it ony 2-3 times until it will get hard again), I'm 80% sure you need a new relay. If you don't know where this relay is located I'll take you a pic under the hood of my '87 Continental on Tuesday.
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