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99 Ford Mustang Braking Issue

I have a 1999 Ford Mustang, automatic, 6 cyl. Several months ago, the passenger’s rear brake started to rub. Figured it was the pads so I changed them. About two weeks later, it started again. I had a shadetree mechanic look at it and ended up putting two different brake calibers on. Each time, the pads would wear within a couple of weeks.

I took the car to a shop. It’s a pretty reputable shop in my town. I since taken it up there 4 different times, each with the same issue. The mechanic told me the 99 mustang had a recall on the parking brake (which was for a manual trans - mine is auto) and he checked everything he knows to check. Not too long ago, he refunded my money for the service.

The rotors have been turned, the lines replaced, calibers replaced (several times), and the master cylinder has been checked.

Just from my driving, it seems that there is just too much force on the caliber and it is wearing out the pads too fast. I’m wondering if it could be the parking brake causing this. If it is the parking brake, would it be safe just to disable it since I don’t use it? Also, what else could be causing this. I really need it fixed because my wife drives the car more than I do with my kids.

Thanks for any help in advance.

Try disconnecting the vacuum line to the booster. Clip it so that the engine doesn’t experience a vacuum leak. Leave the connection at the booster vented. See if the problem goes away.

Post back the result.

Note: If you do as The Same Mountainbike suggests you will not have any power assist to your brakes. You will still have brakes, but they will require considerable extra effort to work. Be careful.

What you are checking for is to see if the vacuum booster is applying pressure to the brakes even when your foot is off of the pedal.

Possibly the emergency brake cable is hanging up. Do you use the emergency brake?

Have you tried raising both rear wheels off of the ground, shifting the gear lever into neutral, and then spinning the wheels by hand to see if one or both is badly dragging?
I’d have to think that with pads going that quickly the wheel, or wheels, should be hard to turn.

If dragging then one might suspect a park brake cable problem or a sticking caliper slide pin. If the calipers were changed the pins should have also been changed at that time and lubricated before installation.

Every time the calibers were changed, the pins were also. I was thinking it may be the parking brake but I’ve never used it. That is why I was wondering if I could just disable it and still have functioning brakes.

Both tires have been lifted and only the passenger rear is hard to turn in neutral.

Possibles; bad caliper not releasing, collapsed rubber brake line not releasing pressure, bad master cylinder, bad power brake vacuum system, parking brake not releasing, ABS or trac control applying braking on that wheel.

Since you have tested most of the other possibles, what about the ABS/trac control system? A bad wheel sensor could be telling the system to stop the wheel from spinning. Perhaps you need to take this one to a Ford dealer to sort out and repair.

If you haven’t replaced the flexible rubber hose at the affected caliper, I would try that first. Those can cause exactly what you are experiencing.

How is the braking power, in general? Have the front brakes been inspected during this time and are they working normally? Wearing normally? Is this all only the passenger’s side? Can you please clarify whether or not the rear flexible lines have been replaced? If so, and given all of the other work, I’m wondering about the proportioning valve, though I confess to knowing too little about them to speculate.