Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSFORD1990RANGER 4WD L4-140 2.3L SOHCREPAIR AND DIAGNOSISBRAKES AND TRACTION CONTROLDISC BRAKE SYSTEMTESTING AND INSPECTION
1990 Ford Ranger 4WD L4-140 2.3L SOHC
Disc Brake System: Testing and Inspection
1990 Ford Ranger 4WD L4-140 2.3L SOHCSECTION Testing and Inspection
BRAKE PAD INSPECTION
Remove the pads/linings from the caliper and inspect for the following:
- The brake lining thickness should be at least 1/16 in (1.5mm) above the shoe backing or any rivet.
- Lining damage. The lining should not be cracked or glazed (shiny, glass or charcoal like appearance).
- Check the flatness of the pads/linings. Place the inboard and outboard lining surfaces together and check for a gap between the lining surfaces. This gap should not exceed 0.13 mm (.005-inch) at the middle of the lining surfaces. This applies to new or used pads/linings.
Replace the pads/linings if any problems are found.
The disc pads/linings have a wear indicator that makes a noise (metallic squeal) when the linings wear to a degree where replacement is required .
BRAKE CALIPER INSPECTION
Inspect the caliper for the following problems:
- Brake fluid leakage near or around the piston dust boot.
- Cracked caliper housing or piston.
- Uneven brake pad wear.
- The inner pad is worn more than the outer pad.
- The pads/linings from the left caliper are worn more than the right caliper (or vice versa).
- Missing or damaged mounting hardware.
- Caliper slide joints, slide pins, and bushings are free of corrosion and nicks
- Tears or cracks in dust boots around caliper pistons and slide assemblies.
- Evidence of excessive heat:
- Bluish purple discoloration of rotor or caliper housing.
- A thin brick red oxidation layer evenly covering all brake components on the hub assembly (not to be confused with the typical rough, and flaky oxidation caused by rust)
If any problems are identified with the above areas, the calipers should be replaced or rebuilt.
The Following Areas Should Also Be Inspected:
- Inspect the flexible brake hoses for cracks or signs of leakage. Replace if any defects are found.
- Inspect the splash guard around the rotor for damage or loose mounting bolts.
NOTE: The splash guard should not he permanently removed. The splash guard helps prevent debris and water from contacting the pad and caliper assembly and also helps funnel air across the brake components to assist in cooling.
- Inspect rear brake operation and adjustment. Rear brakes which are out of adjustment will require the front brakes to do more work, causing accelerated wear and possible overheating.
Remove the pads/linings from the caliper and inspect for the following:
- The brake lining thickness should be at least 1/16 in (1.5mm) above the shoe backing or any rivet.
- Lining damage. The lining should not be cracked or glazed (shiny, glass or charcoal like appearance).
- Check the flatness of the pads/linings. Place the inboard and outboard lining surfaces together and check for a gap between the lining surfaces. This gap should not exceed 0.13 mm (.005-inch) at the middle of the lining surfaces. This applies to new or used pads/linings.
Replace the pads/linings if any problems are found.
The disc pads/linings have a wear indicator that makes a noise (metallic squeal) when the linings wear to a degree where replacement is required .
BRAKE CALIPER INSPECTION
Inspect the caliper for the following problems:
- Brake fluid leakage near or around the piston dust boot.
- Cracked caliper housing or piston.
- Uneven brake pad wear.
- The inner pad is worn more than the outer pad.
- The pads/linings from the left caliper are worn more than the right caliper (or vice versa).
- Missing or damaged mounting hardware.
- Caliper slide joints, slide pins, and bushings are free of corrosion and nicks
- Tears or cracks in dust boots around caliper pistons and slide assemblies.
- Evidence of excessive heat:
- Bluish purple discoloration of rotor or caliper housing.
- A thin brick red oxidation layer evenly covering all brake components on the hub assembly (not to be confused with the typical rough, and flaky oxidation caused by rust)
If any problems are identified with the above areas, the calipers should be replaced or rebuilt.
The Following Areas Should Also Be Inspected:
- Inspect the flexible brake hoses for cracks or signs of leakage. Replace if any defects are found.
- Inspect the splash guard around the rotor for damage or loose mounting bolts.
NOTE: The splash guard should not he permanently removed. The splash guard helps prevent debris and water from contacting the pad and caliper assembly and also helps funnel air across the brake components to assist in cooling.
- Inspect rear brake operation and adjustment. Rear brakes which are out of adjustment will require the front brakes to do more work, causing accelerated wear and possible overheating.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.