1. Brake Hose: A restricted or internally damaged brake hose can prevent the caliper piston from retracting fully. The hose could be collapsing internally, restricting flow. This is a highly probable cause given your other replacements. Replace the brake hose completely. Don't just try to "bleed" it, as internal damage is likely not easily remedied.
2. Brake Line: Similar to the hose, a restricted or damaged brake line leading to the caliper could be the culprit. Carefully inspect the line for kinks, rust, or damage. If damaged, replace the entire section from the distribution block to the caliper.
3. Caliper Piston Problem (despite replacement): While unlikely if you've replaced the caliper, there's a very small chance the new caliper is defective or isn't properly seated. Double-check the caliper installation, making sure it's correctly bolted and the slide pins are moving freely with lubrication. A sticking piston could still be an issue in this scenario despite the part being new.
4. Master Cylinder: While less likely, a faulty master cylinder could be applying excessive pressure to the left front brake circuit. However, if other brakes are working fine, this is less probable. Check for leaks and uneven pressure application across all brake lines.
5. Wheel Cylinder (if applicable): Is this a drum brake system? If so, a sticking wheel cylinder needs to be checked.
6. ABS System (if equipped): If your truck has an Anti-lock Braking System (ABS), a problem within the ABS system could be causing this issue. A malfunctioning ABS sensor or module could lead to uneven brake application. This is less likely but worth considering if you have an ABS system.
Troubleshooting Steps:
1. Visually inspect the brake hose and line: Look for kinks, rust, swelling, or any signs of damage.
2. Replace the brake hose: This is the most likely solution at this point.
3. Bleed the brakes: After replacing the hose (or any other component), carefully bleed the brakes to remove any air in the system. This is crucial for proper brake function.
4. Inspect the caliper installation: Ensure the caliper is properly installed, the slide pins move freely and are lubricated, and the caliper piston is properly retracting.
5. Check for fluid leaks: Inspect all brake lines, hoses, and connections for leaks.
Important Safety Note: Working on brakes is dangerous. If you're not comfortable performing these repairs yourself, take your truck to a qualified mechanic. Brake failure can lead to serious accidents.
