Initial Inspection and Diagnostic Overview

Inspection and Verification

Preliminary Checks

NOTE: Always check the fluid level in the brake master cylinder reservoir before performing the test procedures. If the fluid level is not at the correct level, add High Performance DOT 3 Brake Fluid C6AZ-19542-AB or equivalent DOT 3 fluid meeting Ford specification ESA-M6C25-A.

NOTE: Prior to performing any diagnosis, make certain that the brake warning indicator is functional.

The first indicator that something may be wrong in the brake system is a change in the feeling through the brake pedal. The brake warning indicator in the instrument cluster and the brake fluid level in the brake master cylinder reservoir are also indicators of system concerns.
If a wheel is locked and the vehicle must be moved, open a bleeder screw at the locked wheel to let out enough fluid to relieve the pressure. Close the bleeder screw. This bleeding operation may release the brakes but will not correct the cause of trouble. If this does not relieve the locked wheel condition, repair the locked components before proceeding.

Brake Booster
Inspect all hoses and connections. All unused vacuum connectors should be capped. Hoses and their connections should be correctly secured and in good condition with no holes, soft or collapsed areas.

Road Test
Perform a Road Test to compare actual vehicle braking performance with the performance standards expected by the driver. The ability of the test driver to make valid comparisons and detect performance deficiencies will depend on experience.
The driver should have a thorough knowledge of brake system operation and accepted general performance guidelines in order to make good comparisons and detect performance problems.
Select a road that is reasonably smooth and level. Gravel or bumpy roads are not suitable because the surface does not allow the tires to grip the road equally. Avoid crowned roads.
A key factor in evaluating brake concerns is the deceleration rate. This varies from vehicle to vehicle and with changes in operating conditions. It is evident how well the brakes are working after just a few applications.
Avoid locking the brakes. Locked brakes are not an indicator of braking efficiency.





Visual Inspection Chart

Vibration When Brakes Are Applied
For vibration concerns when brakes are applied, carry out the following procedure.
1. Verify the concern.
^ Brake vibration concerns are caused by uneven disc wear or lining transfer and should be verified with a test drive since these conditions are difficult to measure with available shop tools.
^ Check Technical Service Bulletins for vehicle specific brake concerns.
2. Remove the wheel and tire assembly.
3. Remove the brake caliper.
4. Inspect the brake linings. Install new pads if the thickness of the lining is below the specification or if cracks in the lining wide enough to see through down to the backing plate are present.
5. Inspect the brake discs.
^ Install new discs if cracked.
^ Resurface the brake discs if the diagnosis has revealed vibration in the steering wheel, seat, or pedal while braking. Heavily scored brake discs, similar to that caused by linings worn down to the backing plate, should also be machined.
6. Measure the disc thickness and record the measurement. For discs that require machining, install a new disc if the thickness is less than 0.60 mm (0.02 in) above the minimum thickness specification cast in the disc. This will make sure that the disc will be above minimum thickness after machining. Do not machine new discs.
7. For vehicles with a two-piece brake disc and hub assembly:
1. Match-mark before disassembly.
2. Remove the brake disc.

3. CAUTION: Do not use an abrasive sanding disc since it will remove paint or other protective finishes from wheel and metal from mounting surfaces, adversely affecting corrosion protection and disc lateral runout.

Remove corrosion from wheel mounting surface, both disc mounting surfaces, and hub mounting surface. A die grinder with Scotchbrite surface conditioning disc, or equivalent, is recommended.
4. Align the match marks and reinstall the disc on the hub.

8. CAUTION: Do not use a bench lathe to machine brake discs.

NOTE: Read the entire operating manual and view the video shipped with the lathe before installing, operating, or servicing the lathe.

Machine the brake disc using Rotunda Hub-Mount Brake Lathe/Pro-Cut 201-00002, or equivalent.
1. Install the hub adapter and silencer belt, if necessary.
2. Install the cutting lathe.

3. NOTE: Total indicated reading target is 0.000 mm (0.000 in), maximum is 0.08 mm (0.003 in).

Adjust lathe oscillation using a dial indicator.
4. Center cutting head, adjust cutting bits, and install chip deflector.

5. NOTE: Depth of cut should be between 0.10 and 0.20 mm (0.004 and 0.008 in). Lighter cuts will cause the bit to heat up and wear faster. Heavier cuts will cause poor disc surface finish.

Maching the brake disc.
6. Remove the lathe and, if installed, the silencer belt.
7. Remove the hub adapter.
9. Remove metal shavings.
10. Install the brake pads.
11. Install the wheel and tire assembly.