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Rear Brakes Stick While the Car Is Parked

Vlad Soare

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Hi guys,

Before Christmas I left the Mustang parked with the handbrake engaged - as I always do - and went on holiday. I returned three weeks later. The next time I wanted to drive it I released the parking brake, shifted into first and started releasing the clutch. As I approached the engagement point nothing happened, I lifted the pedal further, still nothing, until eventually the car sprang forward with a loud bang. As I started driving I noticed a rhythmic noise coming from the rear wheels, and the brakes made an awful noise when applied. Both of these noises went away after braking several times.
What happened is clear. The rear brakes had stuck due to the car having been parked outside in the winter with the handbrake engaged. Mistake. I shouldn't have done that.
I've been using the handbrake religiously in all my cars for over twenty years, all of them being parked outside all year round, and never had a problem. Whenever I heard someone saying "don't use the handbrake in the winter lest it stick" I used to scoff at them. But the Mustang seems to be an exception.
Oh well, lesson learned.

But here's the strange thing. I haven't been using the handbrake since then. I turn the engine off, shift into first, release the clutch and take my foot off the brake. There's a bit of a slope where I park, and after taking my foot off the brake the car moves forward for a fraction of a second, before stopping due to it being in gear. So I'm confident that at the time I get off the car the brakes are really released, and the only thing that keeps the car from moving is the gearbox.
And yet the rear brakes still stick while the car is parked! The next day I press the clutch pedal, and the car, despite being on a slight slope, isn't moving. I start the engine, start releasing the clutch, and it springs forward with a loud clunk.
How come?

What could cause this? And most importantly, what can I do to avoid it?

Thank you.
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Iā€™ve driven in very snowy winters since the car was new in 2016, and I had the same issue. Even with the hand brake off, still the big pop when first moving.

I think itā€™s a result of the rotors glazing with rust, and sticking to the pads. This is my best guess as I didnā€™t have the issue with my new slotted rotors and ceramic pads this last winter.

Of course, my new garage is warmer than the last, so itā€™s possible that water freezing the pads and rotors together may have been the problem too.

By the way, I really enjoyed my time in Bucharest, and I spent a few months in Sibiu and the FĆ¢gĆ¢raș mountains...beautiful country.

- Mike
 
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Vlad Soare

Vlad Soare

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What I don't really get is how the pads can stick to the rotors if the brakes are off. They're not touching the rotors, are they?
Now, if I washed the car after having parked it, and water got in between the pads and the rotors and froze overnight, it would make perfect sense, of course. But I'm not doing that.

How does the handbrake work in the Mustang? Does it use the same caliper and pads as the regular brake? Or are there little shoes inside the rotor? If it's the latter, then maybe it's the shoes that are acting up, or maybe the return spring or something?

By the way, I really enjoyed my time in Bucharest, and I spent a few months in Sibiu and the FĆ¢gĆ¢raș mountains...beautiful country.
I'm happy to hear that. Bucharest is OK-ish, though not very tourist-friendly, but the Sibiu-Făgăraș area is very nice indeed. We have a small holiday house near Brașov, and we often drive to Făgăraș and its surrounding area. I love that place.
 
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GuardEcoBeast

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The rear caliper is the emergency . When you pull the lever, the piston spins out of the caliper. It is probably seized if the noise and feel is still there.
 

cmxPPL219

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Hi guys,

Before Christmas I left the Mustang parked with the handbrake engaged - as I always do - and went on holiday. I returned three weeks later. The next time I wanted to drive it I released the parking brake, shifted into first and started releasing the clutch. As I approached the engagement point nothing happened, I lifted the pedal further, still nothing, until eventually the car sprang forward with a loud bang. As I started driving I noticed a rhythmic noise coming from the rear wheels, and the brakes made an awful noise when applied. Both of these noises went away after braking several times.
What happened is clear. The rear brakes had stuck due to the car having been parked outside in the winter with the handbrake engaged. Mistake. I shouldn't have done that.
I've been using the handbrake religiously in all my cars for over twenty years, all of them being parked outside all year round, and never had a problem. Whenever I heard someone saying "don't use the handbrake in the winter lest it stick" I used to scoff at them. But the Mustang seems to be an exception.
Oh well, lesson learned.

But here's the strange thing. I haven't been using the handbrake since then. I turn the engine off, shift into first, release the clutch and take my foot off the brake. There's a bit of a slope where I park, and after taking my foot off the brake the car moves forward for a fraction of a second, before stopping due to it being in gear. So I'm confident that at the time I get off the car the brakes are really released, and the only thing that keeps the car from moving is the gearbox.
And yet the rear brakes still stick while the car is parked! The next day I press the clutch pedal, and the car, despite being on a slight slope, isn't moving. I start the engine, start releasing the clutch, and it springs forward with a loud clunk.
How come?

What could cause this? And most importantly, what can I do to avoid it?

Thank you.
Yeah, there are a lot of various factors at play that have made you experience this for the first time in the Mustang, all probably coming together to form the perfect storm, if it were - factors such as the specific rear pad compound, any precipitation like rain or snow, wind, temperature, humidity, length of time, etc., etc.

You can definitely do what you have outlined to prevent it in the future (and maybe add a wheel chock or a brick for extra security).

As for still experiencing the issue, I find that a good amount of driving and using the brakes (also, braking relatively harder than usual) will be required to remove the surface rust/corrosion when this particular binding issue occurs. I'm not sure how often you drive the car, but if it isn't often, try this out - it might work. The friction from using the brakes continuously should scrape it all off.

On a related note, this can also happen when washing the car at home, and temps are cool; if the car isn't driven after thoroughly washing it, and just parked up, this binding can happen to both front and rear brakes, because of all the water on the rotors and pads that is just there to sit.

What I will usually do to prevent this, is drive around the street and press the brakes continuously; or, even just driving it forward and backward on the driveway, using the brakes to remove some water and the surface rust on the bare rotor.
 

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Vlad Soare

Vlad Soare

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As for still experiencing the issue, I find that a good amount of driving and using the brakes (also, braking relatively harder than usual) will be required to remove the surface rust/corrosion when this particular binding issue occurs. I'm not sure how often you drive the car, but if it isn't often, try this out - it might work. The friction from using the brakes continuously should scrape it all off.
You may be right about that. I thought a short drive was enough to scrape all the rust off, but apparently it wasn't. Yesterday a took a longer drive and braked more - and harder - and this morning the brakes weren't stuck.
Thanks. :like:
 
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cmxPPL219

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You may be right about that. I thought a short drive was enough to scrape all the rust off, but apparently it wasn't. Yesterday a took a longer drive and braked more - and harder - and this morning the brakes weren't stuck.
Thanks. :like:
Np!
To add, sometimes you can even see if there is any rust/residual surface corrosion left over when you see the pad shape burnished on the rotor face, and the rest of the rotor face is very clean.
Glad this was a simple fix for you :thumbsup:
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