The customer reported a loud clunk noise when the 4-wheel drive was engaged and disengaged, poor brake function, and very poor fuel mileage. Our inspection found that the 4-wheel drive system was operating normally, but found both front brake calipers were seized and the brake hoses were collapsed. The brake repair was completed, and the customer noticed a dramatic difference when driving.
Diagnosis
The vehicle was in good condition and seemed to be cared for with regular maintenance. However, pickup trucks are often used for light-duty driving, and their 4-wheel drive and heavy-duty brake systems do not get used frequently enough to keep them functioning correctly.
The reported symptom was a clunk noise when the 4-wheel drive system was operated, and the truck felt like it was pulling to one side when driving.
The technician did a test drive and attempted to replicate the clunking noise. The only noise heard was the normal sound of the actuator engaging and disengaging the 4-wheel system. The pulling of the steering to one side was also confirmed.
During the test drive, our technician noticed when the vehicle was stopped, it would not move forward with their foot off the brake pedal. A significant amount of throttle was required to make the vehicle move. This hinted at a problem with the front brakes.
Inside our auto repair shop, the technician connected a computer scan tool and found no error codes. When the 4x4 transfer case was engaged and disengaged, there were no odd noises. This indicated the transfer case was operating normally. This strongly indicated no problems with the 4-wheel system and the problem was with the brakes.
However, the technician had a strong feeling there was something wrong with the brakes. They also noticed the brake pedal felt very hard when depressed, and the brakes did not seem to have much braking power compared to the pressure applied to the brake pedal. This hinted that there was a major brake drag problem.
Next, the technician inspected the vehicle for evidence of a brake problem. The steering pulling issue and having to use an above normal amount of throttle to get the vehicle to move were strong indicators of a brake problem. Both front wheels were removed and an attempt to compress both front brake calipers showed that they were seized and holding the brakes partially applied. This definitely would cause the brake drag and a slight pulling of the steering.
The brake pads and rotors were near the end of their life so our technician recommend a complete front brake service including brake caliper replacement, brake pad replacement, brake rotor replacement, and a brake fluid flush and replacement.
Due to the vehicle's age and high mileage, and what looked to be original parts, brake hose replacement was done on both sides. Brake hoses deteriorate over time and can cause plugged brake lines and dragging brakes. It is best practice to replace the brake hoses when a vehicle exhibits symptoms of sticking brake calipers and dragging brakes.
Cause
There are two common causes for stuck or seized brake calipers: corrosion caused by moisture-contaminated brake fluid and collapsed brake flex hoses not releasing the brake fluid pressure holding the calipers partially applied.
Brake caliper pistons need to move freely so that they can retract when the brake pedal is released. If the brake caliper pistons are corroded into the caliper housing and can not move freely, the brakes will drag on the brake rotor and prevent the wheel from rotating freely.
The second most common reason for a stuck brake caliper is a blocked brake flex hose. The inner lining of the brake hose separates and restricts or blocks the flow of brake fluid. This hydraulic fluid blockage prevents the brake caliper from releasing the brake pads.
The clunking noise when the 4-wheel system was engaged and disengaged resulted from the brake calipers and brake pads moving when the front wheels were connected to the power from the transmission by the 4x4 system.
The steering pull was caused by one brake caliper being seized to a greater degree than the other side, which caused the steering to pull towards the side with the tighter brake caliper.
FAQ
What are the symptoms of a dragging caliper?
The symptoms of a sticking brake caliper include:
- vehicle pulling to one side during braking,
- steering pull to one side when driving straight ahead,
- uneven wear on brake pads,
- brake pad over-heating,
- burnt brake smell or unusual odors after driving,
- decreased fuel mileage.
Can a stuck caliper piston cause brake drag?
Yes. The caliper piston can stick inside the caliper housing. When the brakes are applied, the piston is forced out and sticks in the applied position. The dragging brakes cause friction, and the excessive heat generated can damage brake pads, brake hoses, brake rotors, axle seals, and wheel bearings.
Brake Repair
Front Brake Service
Our Ford truck brake technician removed the defective brake calipers and worn brake pads. The worn brake rotors were removed and replaced with quality new brake rotors. New brake calipers with new brake pads and mounting hardware were installed.
Front Brake Hose Replacement
The technician replaced the brake hoses on both sides. First, they disconnected the brake hoses and then let the old brake fluid drain before installing the new brake hoses.
Brake Fluid Replacement
The old brake fluid was drained, and the brake hydraulic system was flushed with new brake fluid, including the master cylinder, ABS pump, brake calipers, brake hoses, and brake lines. The brake system was filled with new brake fluid, and then the brake system was bled to remove any air.
Quality Inspection
A final inspection of the brake work performed was done, the wheels were installed, and the wheel nuts were torqued to factory specifications. Next, the vehicle was road tested, and a brake pad break-in procedure was done. A final inspection of the vehicle was done before the vehicle was released to the customer.
Tips
Truck brakes typically last much longer than the average car or SUV. There are two services that can extend the life of the brakes and prevent brake problems. Depending on the driving conditions the vehicle operates in, a brake inspection and brake hardware cleaning and lubrication will help prevent seized brake calipers and unsafe brake function. The second recommended brake service is a brake fluid flush every two years, regardless of the distance driven. Regular brake fluid replacement is based on time and prevents brake fluid contamination, which causes brake caliper seizures and costly premature brake service.
Replacing brake hoses when a brake service is done can prevent unsafe brake problems. The original brake hoses on Ford trucks fail more often than other vehicles. Replacing the hoses is a good preventative action and can prevent premature wear of replacement brakes and brake problems.
Contact State Street Auto Service for all Ford truck brake service and repair in the Ann Arbor, MI area. We are a Ford truck specialist.