Ford Bronco ABS Wheel Speed Sensor Guide for 1987-1996 Models
Fix your ABS light, erratic speedometer, and hard shifting by replacing the single sensor on your rear differential.
- The single ABS sensor on the rear differential is the most likely cause for a combination of an ABS light, dead speedometer, and hard shifting.
- Replacement is a very simple DIY job, requiring only a 10mm wrench and about 30 minutes.
- For this part, premium aftermarket brands like Delphi, NGK, and Standard Ignition offer reliable, long-lasting performance.
- Before replacing the sensor, always check the attached wiring for any visible breaks or corrosion, which can cause the same symptoms.
Understanding the ABS Sensor in Your Bronco
Most 1987-1996 Ford Broncos use a simple but effective Rear-Wheel Anti-lock Brake System, often called RWAL. Instead of a sensor at each wheel, this system uses a single sensor mounted on the rear differential housing. This sensor, also known as a Vehicle Speed Sensor (VSS), reads the speed of the rear axle and sends that information to the truck's computer. This one signal controls the anti-lock brakes, the speedometer, and the shifting for automatic transmissions like the E4OD. Some later models (1993-1996) were available with optional four-wheel ABS, which adds sensors at the front wheels, but the rear sensor is the most common failure point 🎬 Watch a mechanic replace the VSS on a similar Ford. and affects the most systems.
Symptoms of a Failing Rear ABS Sensor
When this sensor starts to fail, it typically causes a distinct group of problems. You will likely experience more than one of these at the same time:
- ABS Warning Light: The 'ABS' light on your dashboard will illuminate and stay on.
- Erratic or Dead Speedometer: The speedometer may bounce around, read incorrectly, or stop working altogether.
- Harsh Transmission Shifting: If you have an automatic transmission, it may shift very hard or at the wrong RPMs because it doesn't know how fast the truck is moving.
- Flashing Overdrive Light: The O/D off light may start flashing in combination with the other symptoms.
Is It the Sensor or Something Else?
While the rear ABS sensor is the most common culprit for these symptoms, a broken wire leading to the sensor or a failed Programmable Speedometer/Odometer Module (PSOM) inside the instrument cluster can cause identical issues. Always inspect the wiring for damage before replacing the sensor. If a new sensor doesn't fix the problem, the PSOM may need to be investigated.
🎬 See how to calibrate your speedometer after a repair.Choosing the Right Aftermarket ABS Sensor
For a vehicle of this age, the original Motorcraft sensor is often discontinued or hard to find. Aftermarket parts offer excellent value and are readily available. The technology is straightforward, and several reputable brands produce reliable replacements. Here’s how they generally stack up:
- Premium Aftermarket (Delphi, NGK/NTK, Standard Ignition): These brands are well-regarded in the industry and are often considered OEM-equivalent in terms of quality and reliability. They are trusted by professional mechanics and are an excellent choice for owners who want the best fit and longest service life.
- Standard Aftermarket (Dorman, Holstein): These brands provide a cost-effective solution that meets OEM specifications. They are a popular choice for DIY repairs and offer a good balance of price and performance, often backed by a solid warranty.
Pro Tip: Easy Installation
Replacing this sensor is one of the easiest repairs you can do on your Bronco. It is held in by a single 10mm bolt on top of the rear differential. The hardest part can be removing the old sensor if it's seized. Spray it with penetrating oil and let it soak before gently prying it out. Clean the mounting hole and apply a little grease to the new sensor's O-ring for an easy installation.
🎬 Watch this step-by-step walkthrough of the rear sensor replacement.Aftermarket ABS Sensor Cost for 1987-1996 Ford Bronco
| Part Tier | Estimated Price |
|---|---|
| Premium Aftermarket (Delphi, NGK, Standard Ignition) | $40 - $66 |
| Standard Aftermarket (Dorman, Holstein) | $22 - $39 |
| Shop Labor (Estimated) | $50 - $120 |
Frequently Asked Questions
Can I still drive my Bronco with a bad ABS sensor?
Yes, but with caution. Your anti-lock braking function will be disabled, meaning your wheels can lock up during a panic stop. More importantly, the erratic transmission shifting can cause unnecessary wear and be unpredictable. It is best to get the sensor replaced as soon as possible.
Is this sensor the same as a Vehicle Speed Sensor (VSS)?
Yes. For this generation of Bronco, the rear ABS sensor is also the Vehicle Speed Sensor (VSS). It provides the speed signal for the ABS, speedometer, and transmission.
Why is my speedometer not working but my ABS light isn't on?
It's possible for the sensor to fail in a way that only affects the speedometer signal initially. However, it's more likely that the issue lies with the instrument cluster itself (the PSOM) or the wiring between the sensor and the cluster.
Are there any recalls for the ABS sensor on my Bronco?
No, there are no active recalls or Technical Service Bulletins (TSBs) from the NHTSA for the ABS wheel speed sensor on the 1987-1996 Ford Bronco.
Helpful Videos
Technical Specifications
OEM Part Numbers: F85Z-9E731-AB
Location: Rear Differential Housing. System: Rear-Wheel Anti-Lock (RWAL). Common Tools: 10mm socket/wrench.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Ford Bronco:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding the ABS Sensor in Your Bronco
- Symptoms of a Failing Rear ABS Sensor
- Is It the Sensor or Something Else?
- Choosing the Right Aftermarket ABS Sensor
- Pro Tip: Easy Installation
- Aftermarket ABS Sensor Cost for 1987-1996 Ford Bronco
- Frequently Asked Questions
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