Antilock Brakes - Pedal Feels Like It Has Extra Travel
Article No.94-5-5
03/09/94
BRAKES - ANTI-LOCK - PEDAL FEELS LIKE IT HAS EXTRA TRAVEL
FORD:
1993-94 TAURUS
LINCOLN-MERCURY:
1993-94 SABLE
ISSUE:
The brake pedal on models equipped with Anti-Lock Brakes may feel like it has long travel. This may be caused by air or leaks in the brake system or by the master cylinder or the valve block.
ACTION:
Inspect brake system for air and/or fluid leaks and repair if found. Refer to the appropriate Taurus/Sable Service Manual, Section 06-03, 06-04 and 06-06. If No leaks exist bleed the entire brake system. Refer to Service Manual, Section 06-09. If the above has not corrected the concern, a bypass condition may exist. Replace the master cylinder or valve block as required. Refer to the Service Manual, Section 06-09 and to the following procedure for service details.
1. Verify the concern - ABS brake pedal feels like it has extra travel.
2. If the concern is verified, inspect brake system for leaks and repair if found. Refer to the appropriate Taurus/Sable Service Manual, Section 06-03, 06-04 and 06-06. Bleed the entire brake system. Refer to the appropriate Taurus/Sable Service Manual, Section 06-09
3. If no leaks exist, bleed entire brake system. Refer to the appropriate Taurus/Sable Service Manual, Section 06-09.
4. If the above steps have not corrected the concern, a bypass condition may be caused by a faulty master cylinder or a faulty valve block. To determine which component is at fault, perform the following test:
NOTE:
IT IS NECESSARY THAT THE FAULT BE REPRODUCIBLE FOR THIS TEST TO PINPOINT THE FAULTY COMPONENT.
a. Remove the low pressure feed hose at the master cylinder and plug the reservoir feed to prevent brake fluid from leaking onto paint and wiring (use dealer-fabricated plug).
b. Secure the low pressure hose above the level of the Hydraulic Control Unit (HCU), Figure 1.
c. Have an assistant apply the brake pedal and watch for brake fluid level rise in the low pressure hose while the pedal travels excessively.
d. If the brake pedal travel is excessive and brake fluid is flowing out of the low pressure hose, replace the valve block (2C266), Figure 2. Refer to the appropriate Taurus/Sable Service Manual, Section 06-09 for hydraulic control assembly removal and installation procedure. Refer to step 5 below for valve block removal procedure.
e. If brake pedal travel is excessive and brake fluid is not flowing out of the low pressure hose, replace the master cylinder assembly (2140). Refer to the appropriate Taurus/Sable Service Manual, Section 06-09 for master cylinder removal and installation procedure.
f. If brake pedal travel is not excessive, the problem is intermittent and the faulty component cannot be pinpointed until the fault is reproducible.
5. After removing the (HCU), use the following procedure to replace the valve block.
NOTE:
THE HYDRAULIC CONTROL UNIT MUST BE REMOVED BEFORE REPLACING THE VALVE BLOCK.
a. Using Ford Metal Brake Parts Cleaner (F3AZ-19579-SA) or equivalent, clean all dirt or other foreign material from the HCU assembly as required to prevent entry of contamination into system when valve block is removed.
b. Dry component thoroughly with shop air.
c. Using light clamping force, hold the HCU assembly in a vise, valve block facing up.
d. Remove the three (3) valve block-to-pump attachment bolts using a no. T-40 Torx driver, and remove the valve block from the pump/motor assembly, Figure 3.
NOTE:
DO NOT DISASSEMBLE THE VALVE BLOCK. ONLY THE THREE (3) BOLTS SHOWN IN FIGURE 3 NEED TO BE REMOVED FOR COMPONENT REPLACEMENT.
e. Install a new metal gasket (EODZ-2C254-A), observing the correct location of the gasket locating tab (TAB TOWARD THE WHEEL PORT SIDE), Figure 3.
WARNING:
INSTALL THE METAL GASKET ONLY AS SHOWN. FAILURE TO INSTALL THE METAL GASKET CORRECTLY WILL RESULT IN BRAKE FLUID LOSS AND/OR POOR BRAKE PERFORMANCE.
f. Position the new valve block on the pump/motor assembly and install the attachment bolts.
g. Tighten attachment bolts to 29 N-m (21.4 lb.ft.).
h. Reinstall the HCU into the vehicle by reversing the removal procedure.
i. Using the Anti-Lock Brake Adapter (T90P-50-ALA), bleed all air from the brake system. Refer to the appropriate model year Service Manual, Section 06-09 for correct brake bleeding procedure.
NOTE:
THE MASTER CYLINDER AND HYDRAULIC CONTROL UNIT MUST BE BLED USING THE ANTI-LOCK BRAKE ADAPTER T90P-50-ALA. IF THIS PROCEDURE IS NOT FOLLOWED, AIR WILL BE TRAPPED IN THE HYDRAULIC CONTROL UNIT, WHICH WILL EVENTUALLY LEAD TO A SPONGY BRAKE PEDAL
Parts Block
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS:
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
940505A Diagnose And Replace 1.1 Hrs.
Master Cylinder
940505B Diagnose And Replace ABS 1.6 Hrs.
Hydraulic Control Unit Valve
Assembly
DEALER CODING
BASIC PART NO. CONDITION CODE
2140 08
OASIS CODES: 301000