Possible brake problem - hissing + metallic squeak

[DingosKidneys]

So, this started on my drive home from work today when I got down to non highway speed and could hear over the wind noise.

It's a kind of hissing noise that increases volume with speed, and is completely absent when standing still ( regardless of engine speed ). Also, some metallic squealing but only when just starting to move from a stop. It doesn't appear to impact handling characteristics - acceleration, steering, stopping all seem to be normal as far as I can tell. It seems like it's coming from the passenger front.

I thought maybe something stuck under the car or up in the wheel well etc.. took a look, not that. So possibly brakes? When I got home, put my hand close to the drivers side brake and passenger side brake in turn, the passenger side felt much hotter.

Any ideas? Can a disc brake become partially engaged? Anything I could do to test this out, anything I should check for before going to the mechanic? I'd rather not drive back and forth to work in case it's something that could be made worse

Appreciate your time, thanks

[nguy3nha]

perhaps your brake master cylinder is seizing up? Jack up the front of the car and place it on floor jacks and try spinning both your wheels manually. I would assume that the passenger side would be harder to turn??

If not, it might even be your wheel bearings.. It's best to to have a trusted mechanic to have a look at it since it sounds like something needs to be either replaced or serviced.. I hoping the latter for you

[peterm15]

Have you had your breaks serviced?

[Wes08M3]

Most likely the brake caliper is seized or the slider pins have seized up. Unless you have the mechanical skills to take the caliper apart and check to see if it is indeed seized and then replace it if need be, just take it to your mechanic to have a look. It's not difficult to do and shouldn't cost you much for diagnosis.

Edit: do it sooner rather than later so that you don't ruin the rotor and pads, that is, if they're still in good condition. But there's a good chance your mechanic will recommend replacing the pads and rotors at the same time.

[peterm15]

^^^
Or you can just jack up the car. Take off the wheel and have someone depress the pedal. You'll be able to see if it's moving.

[Wes08M3]

^^^
Or you can just jack up the car. Take off the wheel and have someone depress the pedal. You'll be able to see if it's moving.

True. But it is sometimes difficult for a novice to tell using this method, since the piston doesn't really move inwards by a very noticeable amount when you press the brakes.

If you want to keep it really basic, you can also jack the car up and see if it takes much more effort to spin the passenger side wheel (by hand) compared to the drivers wheel (press the brakes a few times first). That should give you a good indication if the caliper is seized.

[peterm15]

^^^.
True enough. Lol.

My only concern on that is a stuck pin. Rather then a seized caliper.

I guess the only way to be sure is to dismantle it and see if the caliper moves freely.

[Wes08M3]

^ Exactly. Fairly simple to do but not everyone has the mechanical skills to do it.

[DingosKidneys]

Thanks for the suggestions guys. I jacked up the front end and tried manually turning the drivers and passengers side wheels. The noise is definitely coming from the passenger side brake. It is difficult to turn. The drivers side is also difficult to turn but is quiet - I say difficult, I'm trying to remember what it's like when I change my wheels for summer/winter. I remember them just spinning freely when jacked up, whereas now I can push them around with my hand but they don't spin, they pretty much just stop as soon as I stop pushing.

It looks like the brake pads are touching the rotors, but I can't say I've ever looked that closely at it. Maybe it always looks like that.

I got a brake service ( recommended 48k maintenance ), that was only about 6000km ago.

Only thing that has changed recently was putting on the summer wheels, but I don't know how that could cause a problem, same ones I had on last year.

Although I'd like to dismantle a caliper just for fun, if I had time and didn't need my car, sounds like I'll be taking it to the shop :)

[peterm15]

If you have the tools and ability it only takes like 5 min.
You only need to remove 2 Allen key bolts to remove the entire caliper and pads.

From there you can see if it's for sure sized or if the pins are just stuck.

[Wes08M3]

Thanks for the suggestions guys. I jacked up the front end and tried manually turning the drivers and passengers side wheels. The noise is definitely coming from the passenger side brake. It is difficult to turn. The drivers side is also difficult to turn but is quiet - I say difficult, I'm trying to remember what it's like when I change my wheels for summer/winter. I remember them just spinning freely when jacked up, whereas now I can push them around with my hand but they don't spin, they pretty much just stop as soon as I stop pushing.

It looks like the brake pads are touching the rotors, but I can't say I've ever looked that closely at it. Maybe it always looks like that.

I got a brake service ( recommended 48k maintenance ), that was only about 6000km ago.

Only thing that has changed recently was putting on the summer wheels, but I don't know how that could cause a problem, same ones I had on last year.

Although I'd like to dismantle a caliper just for fun, if I had time and didn't need my car, sounds like I'll be taking it to the shop :)

The front tires don't really spin all that freely since your turning parts of the drivetrain as well, the rears will spin relatively freely. But if you noticed that it was harder to turn the passengers side wheel, you probably have a problem there.

The brake pads are ALWAYS in contact with the rotor, so no worries there, that's normal.

[DingosKidneys]

If anyone is curious about the resolution, apparently my tires picked up a rock that was jammed in the caliper, couldn't see it. All 'fixed', diagnosis and the fix a freebie from the mechanic :)

[peterm15]

If anyone is curious about the resolution, apparently my tires picked up a rock that was jammed in the caliper, couldn't see it. All 'fixed', diagnosis and the fix a freebie from the mechanic :)

Who'd a thunk it.

Good thing it all worked our easy.

[peterm15]

I have faced many problems like that i tried to fix them by myself and with the help of my friends but we were unable to fix it that why i am suggesting everyone that do not waste your time and consult you garage or reputed car care center.

Or if you have any mechanical ability.

The hardest part of a brake job is jacking the car up.