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I forgot to release the hand brake while I'm driving at around 4 to 5km. What will happen to my rear brakes?

4 Answers 4

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If this was a one time occurance the damage should be minimal. If the brake shoes were worn or damaged the lining material may have cracked from overheating. This is rare if they were in good shape.

The damage done will depend on the type of parking brake brake along with the extent of wear before the incident. The older design of parking brake used the service brake shoes (the one that normally stop the car) as the parking brake, they are activated by a cable system instead of the normal brake hydraulics system.

Typically if the brake shoes were in good shape a manual readjustment of the shoes will return everything to normal. The manual adjustment consists of turning an adjusting screw inside the brake drum. Most vehicles have an access hole so this can be done without removing the drum. If your car has rear disc brakes you may have a small set of brake shoes behind the rotor that act as the parking brake. If these shoes are worn they will have no effect on normal braking.

Similar to drum style brakes these are adjustable, however the adjustment involves removing the caliper and rotor to get at the adjuster. On some Subarus and Saabs the parking brake is part of the front brake caliper, it uses the normal brake pad as a parking brake. The pad is moved mechanically via a cable. In this type no readjustment is needed, as the pads self adjust with every use.

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  • I've had the parking brakes freeze "on" in my car a few times in the Winter. Taking it nice and slow I was able to limp the car home to my warm garage to thaw them out. Did generate a good deal of heat, but no obvious extra wear (and not enough heat to boil the brake fluid). YMMV of course, especially if you drove fast with them locked on. Nov 19, 2012 at 14:58
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Depending on to what degree of "on" you had it, anywhere from nearly none to possibly some. Leaving it on the last click (or two, or three, depending on how much slack there is) usually doesn't engage the brakes at all. Especially on older cars.

However, if you left it on fully engaged, then it could wear the brake shoes or pads prematurely, and cause damage to them. It would also probably start smelling as well.

So if your car wasn't on fire, you probably wore them out a bit more than usual but nothing to be concerned about. Especially if it didn't even smell like burning brake pads.

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  • Could you please describe more symptoms of this. Recently I changed a faculty parking brake sensor, but sometimes it is lit as 'On' in red. So how can I know the brake is on? I just thought it's acceptable for a Chinese knockoff. Sep 25, 2018 at 21:54
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    All the cars I've worked on, the parking brake sensor is separate from the actual activation of the brakes. That is, the sensor might be on the handle (or stem, if a pedal) of the brake lever itself, so as soon as the lever leaves the resting position the light comes on. But, the slack in the system is just being drawn up and actual pads won't really come into contact until a little before you can 'feel' the activation. Granted, this varies greatly between cars, new cars tend to be very taught and precise.
    – Nick
    Sep 25, 2018 at 23:22
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If car still brakes effectively without shuddering all should be well.Handy hint-if your car has discs and you're unsure when to change pads visually inspect.If pad material is thinner than the backing plate time to change.In any case you should hear screecher if they're are due but don't rely on it.Some are known to remove them

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...in other words: no damage, only that the parts would get a lot hot and some little degree of worn out for the brake shoes/pads. One thing very important tho: if that happens again NEVER pour water to the brakes, even if they smoke. Never do that, those metals will get very hot, if you water them, they will bend and in the typical scenario, they may crack.

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