Brakes go to floor sometimes

2001 FORD EXPLORER
163,000 MILES • 0.5L • 6 CYL • 4WD • AUTOMATIC
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DROCK72
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Recently I have been having problems with my brake pedal going to the floor. I have had new brake pads put on and the master replaced. Still it does not always want to stop right away. Especially if I am turning and need to stop (like into a driveway).
Brake booster appears to be working and there doesn’t appear to be any leaks.
As I said I’ve had it has been in the shop 2 times in the last 2 weeks to have new brake pads put on and master replaced. (Along with other service).
When the brake pedal fades it almost feels like the anti-lock brakes are trying to kick in.
I am planning on changing the front axles and hubs next because of the article about axle bearings being a potential problem.
Jul 21, 2020 at 4:16 PM
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KASEKENNY
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Just to clarify the issue, when this happens and the pedal drops, does it feel like it is vibrating as well and you hear a buzzing noise?

The fact that you are thinking it feels like an ABS activation is probably what is happening. If this seems like it happens in a turn then most likely you have a speed sensor issue and the ABS thinks that one tire is slipping and so it pulses the brakes. When this happens the pedal does feel like it drops. Have they found any codes when this happens?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Also, is there a chance that you just replaced one or two tires?

The way to rule this out is to graph all the wheel speed sensors with a scan tool and then make turns to get this to act up and watch the graph. Each of the wheel speed signals should remain steady and pretty even. Clearly they are going to vary a little bit but we are looking to see if one or two of them are a different speed by more then 2 or 3 MPH when this happens. Obviously we are going to need to have a scan tool capable.

Let me know about this info and we can go from there. Thanks
Jul 21, 2020 at 4:30 PM
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DROCK72
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ABS light has never come on.
All tires are newer Hankook.
When it happens it as you’re coming slowly to a stop or slowly making a right hand turn.
Also, I noticed if I pump the brakes quickly 1-2 x before coming to a stop it usually does not happen.
Jul 21, 2020 at 5:25 PM
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