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Pete
Pete, Auto Service Technician
Category: Ford
Satisfied Customers: 29116
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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I own a 2011 Ford Edge. I am having a brake problem. Braking

Customer Question

I own a 2011 Ford Edge. I am having a brake problem. Braking under normal conditions everything works great. The car comes to a nice smooth stop with no issues. The problem happens when braking hard. The driver side front brake feels like the caliper is constantly grabbing and fully releasing in long one second intervals making it impossible to stop quickly. The braking is very rough and it shakes and jerks the entire car. I have replaced the driver side caliper and both front rotors. Brake pads are still in good condition. Prior to this issue I had replaced the master cylinder and the brake booster. This issue started several weeks after the master cylinder and brake booster were replaced.
Submitted: 2 months ago.
Category: Ford
Expert:  Pete replied 2 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

What can happen is if the drivers front wheel speed sensor is sending a false signal on the wheel speed for that wheel this causes the anti lock system to engage and release this brake as it thinks this wheel is in a skid situation.

For example lets say your slowing hard from like 20 MPH.The other 3 wheel speed sensors are sending a signal of 20 MPH and down as you slow down but shows this signal evenly to the abs computer.The drivers front is going from 20 MPH to 0 MPH instantly so the computer thinks that wheel is skidding and in return it releases the brake to try and take it out of the skid and then re applies it.

What should be done is to have a compatible scan tool plugged into your vehicle to have the codes read out of the abs computer.The scan tool is also used to monitor the wheel speed sensor signal while this is occuring when stopping to see if the sensor is sending a false signal needing replaced.

Usually the master cylinder and brake booster will not cause this fault with only one brake acting up.It would have caused issues with either both front or both rear brakes or all brakes acting up.This sounds more like a faulty wheel speed sensor on the drivers front side.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated ( should be a link to click on here or above).You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 2 months ago.
I replaced the left front speed sensor today and that did not correct the problem.
Expert:  Pete replied 2 months ago.

Did you have the speed sensor signal observed with a scan tool to be sure it needs to be replaced?

Customer: replied 2 months ago.
No I didn't have the tool so it was cheaper to just replace it.
Expert:  Pete replied 2 months ago.

O.k.,no problem

Since this sensor was replaced, the caliper was replaced as well as the brake pads and rotor the only other cause I see is a fault with the anti lock brake ecu or anti lock brake hydraulic unit itself.The brake booster or the master cylinder if they were at fault would cause braking issues with all brakes.But the anti lock brake hydraulic unit controls each caliper individually and it may have an issue with air trapped in it needing to be bled out ( this is a bleed procedure that has to be done with a scan tool to run the automated bleed to purge air from it) or it has an internal mechanical fault needing replaced.

I would start with having the automated bleed procedure done to purge any trapped air in the hydraulic unit.Then if the issue continues it may need replaced.

Let me know if you need anything else and feel free to rate my help here or above ( should be a link to click on ) as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete