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George H.
George H., ASE Certified Technician
Category: Car
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1993 lincoln: the brake pressure switch..disconnect..recall..master

This answer was rated:

where is the brake pressure switch located on a 1993 lincoln mark VIII.I'm trying to disconnect it because of the ford recall on these switches.I don't see it anywhere on the master brake cylinder where most pictures show it located.

Hello I will help you with your question,


If you follow the metal brake lines from the master cylinder there is a brake proportioning valve near the steering shaft. The SCDS or brake switch is located on the end of the valve on your vehicle.


Here is a copy of the bulletin for the recall, let me know if you have further questions about this


Thank you


Table of Contents

SCDS Identification

The Speed Control Deactivation Switch (SCDS) involved in Recall 05S28 and the revised SCDS is illustrated below. See Figure 1.

Note that the revised SCDS has a different electrical connector. A jumper adapter (which is included in the parts kit) is required when replacing the old SCDS with the revised SCDS.

SCDS Location

In most late model year vehicles involved in this recall, the SCDS is located on the master cylinder. In early model year vehicles (1992-1998), the SCDS may be located on the master cylinder but is often found on a brake line distribution block or on the brake proportioning valve. If in doubt, just follow the metal brake lines from the master cylinder until the switch is found.

^On early model year E-Series vehicles, the SCDS is located on the left frame rail.


^On E-450 models only, remove the 3 screws and position the coolant degas bottle forward to allow access to the SCDS and servo.


^On F-53 vehicles, if the SCDS is not located on the master cylinder, it may be located in a brake line junction block approximately 457 mm (18 in) below the master cylinder. It may be necessary to reposition wiring harnesses and/or remove add-on equipment in order to locate the switch.


^On 1993 MARK VIII vehicles, the steering wheel intermediate shaft needs to be disconnected from the inside of the vehicle and the outside of the vehicle, and then positioned upwards to gain access to the SCDS.


-When the intermediate steering shaft is disconnected, the steering wheel must be in the LOCK position to prevent damage to the clockspring.


-During installation of the intermediate steering shaft, new bolts must be installed. Tighten the bolts to 49 Nm (36 lb-ft).


^On 1994-1998 MARK VIII vehicles, the SCDS is located underneath the right front fender splash shield in front of the right front wheel. It is not necessary to remove the right front wheel to access the SCDS. Turn the wheel all the way right and position the front of the fender splash shield aside.


^On all Mark VIII vehicles (except 1993), the speed control servo is located underneath the left front fender splash shield in front of the left front wheel.



The new universal fused jumper harness has a double fuse instead of a single fuse. See Figure 2.



NOTE :On E-15012501350 and MARK VIII, it may be necessary to lift the vehicle to disconnect the SCDS.


Disconnect the SCDS and inspect the harness connector (See Figure 3) for the presence of brake fluid.

^All vehicles except 1993 Mark VIII: If there is no evidence of brake fluid on the connector, install a Fused Jumper Harness.


-On 1993 Mark VIII vehicles with no evidence of brake fluid on the SCDS harness connector, replace the Speed Control Deactivation Switch but do not inspect or apply electrical grease to the speed control servo connector.


^If there is evidence of brake fluid on the connector, replace the Speed Control Deactivation Switch, inspect and apply electrical grease to the appropriate connectors.



1.Connect the fused jumper harness to the SCDS and the vehicle harness.


2.Secure the jumper harness to the existing harness with tie straps, making sure the fuse holders are positioned vertically with the cap facing upward. Wrap the tie straps underneath, then over the top of the existing harness and verify proper fuse holder orientation. See Figure 4.



NOTE :The brake pedal must not be depressed during the removal and replacement of the SCDS.


1.Check the brake fluid level at the master cylinder and, if necessary, fill to maximum fluid level.


NOTICE :DO NOT apply fluid to the electrical connector or damage to the connector may occur.


NOTICE : The 1994 Capri Brake Repair Kit contains a brass sealing washer. Install the brass washer onto the SCDS before installing it on the vehicle.


2.Add a few drops of Motorcraft High Performance DOT 3 Motor Vehicle Brake Fluid, PM1-1 or PM-1-C (US), CPM-1-C (Canada), to the fluid port at the threaded end of the new SCDS. See Figure 5.


NOTICE :Do not allow any foreign material to enter the master cylinder port once the SCDS is removed.


NOTE :Call the Special Service Support Center for assistance if brake fluid does not flow from the SCDS fitting when the SCDS is removed.


NOTE :If the new SCDS is not installed immediately after the original switch is removed, the master cylinder brake fluid could drop below the minimum level and air could enter the brake system. If this should occur, air must be bled from the brake system at all 4 wheels. In this situation, the labor to bleed the brake system will not be covered under this program.


3.Remove the SCDS.


4.With the brake fluid reservoir cap removed, observe for brake fluid dripping/draining from the SCDS fitting. As soon as brake fluid begins to bleed from the fitting, install the new SCDS.


5.Tighten the new SCDS as follows:


^18 Nm (159 lb-in) - all vehicles except 1994 Capri.


^13 Nm (115 lb-in) - 1994 Capri.


6.Check the brake fluid level at the master cylinder, fill to maximum fluid level and install the brake fluid reservoir cap.


7.Disconnect the speed control servo and inspect the vehicle harness connector for heat damage. See Figure 6.


^If no heat damage is found at the speed control servo connector (even if there is presence of brake fluid in the connector), proceed to the next step.


^If the speed control servo connector is heat damaged, call the Special Service Support Center for further instructions.


8.With the speed control servo disconnected, use shop air only to blow the SCDS harness electrical connector and the servo connector dry of any trace of brake fluid. Do not use any type of solvent to clean the connectors.


9.Cut approximately 3 mm (1/8 in) off the grease tube applicator tip.


10.Before installing the jumper harness, fill the vehicle harness end of the jumper (male pin connector end) with Motorcraft Electrical Grease II XG-15-A. See Figure 7.


11.Install the adapter jumper harness by connecting it to both the SCDS and the vehicle harness. Using the provided tie strap, secure the jumper harness to a nearby component such as the speed control cable or another wire harness.


NOTICE :Be sure to apply and adequate amount of grease to the vehicle harness connector only. DO NOT apply the grease directly to the connector of the servo module.


12.Apply a 5 mm (3/16 in) high bead of Motorcraft Electrical Grease II XG-15-A across the entire width and length of the servo vehicle harness connector. See Figure 8.



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