Squeaking sound from the wheels after taking out of storage

Question

I have a 1991 Mazda Miata that I have had stored in a Garage for the past 6 months or so. After taking it out of hibernation a few weeks ago, there has been a rather loud squeaking noise coming from the wheels that I can hear echoing off of cars as I drive down the highway in traffic, and on occasion I can hear it while driving through town.

It speeds up in frequency as I speed up, and slows down when I slow. It seems to be unrelated to RPM, and is not affected in volume when applying the brakes, or even the parking brake.

My initial thought is that I may have rusted out something related to the brakes, as it was rather damp in the garage, and I had the parking brake on the whole time it was stored, even though I didn't need it (my mistake, I know).

I don't have many tools at home, and I know very little about cars, but I was wondering if there was something that I could do or check to identify/resolve this issue, before/without bringing it in to a mechanic. Is it damaging the rotors to drive like this? How could I go about diagnosing the real issue?

I am able to provide more info if needed, you will probably have to tell me what to do in order to get you this info, as if I were a 5 year-old though :)

I have looked at Rhythmic squeaking sound from front wheels but I dont think that it is related to my issue, though I may be wrong. Please inform me if so.

Answer 1

There's a few likely culprits:

1. If the sound is coming from one of the back wheels it could be that the parking brake is not releasing properly. Most cars have a separate braking system for the parking brake, the Miata (i.e MX5 depending where you are) is different as it uses an alternative method for activating the parking brake, so I'll split this into 2 answers depending on what system you have:

   1.a The majority of cars parking brakes are a separate cable operated drum brake inside the rear brake rotors. In this case the squeaking sound would change by RPM but not by braking as it's a separate mechanism. If you pull the handbrake (while moving slowly and making sure you are clear of other cars) the squeaking sound would likely change. To clear it I would try pulling the handbrake up and putting it down repeatedly while stopped to see if I could free the mechanism. If it won't release you'll need to get a mechanic to take the brake rotors off and give the parking brakes a service

   1.b The Miata/MX5's rear brake has a separate cable operated mechanism to operate the brake piston. There is a spring which pushes the parking brake back out when released. Similar to the drum brake system this mechanism can become seized, although the sound may not change when you test the brake as described above. Exercising the parking brake may free it, if not you'll need to have someone look at it. If the spring and cable has some corrosion cleaning and lubricating it may be all it needs, if it's internal to the caliper it will need to be repaired or replaced.

2. A brake caliper could be seized on any wheel, front or back. The calipers squeeze the brake pads against the rotors when you press on the pedal, they are supposed to release when you let up on the pedal, if one is a bit rusty it may be keeping a pad held against the rotor, causing the squeal. Again you can try to exercise the brakes, stamp hard and release again and again. If it doesn't go away then you'll need to get the caliper serviced

3. It could be a wheel bearing, although that sounds less likely as they usually make a grinding noise rather than a squeak if they are about to go. There's nothing as a driver that you can do to remedy that, the bearing would need to be replaced

4. Most newer cars have electronic pad wear sensors, older ones have mechanical wear sensors which squeal once a pad has been worn past a certain point. You would have almost certainly have had the squeal before you put the car into storage if that were the case, the pads are going to wear in your garage

If I were to put money on it I'd go with the seized caliper first and then a seized parking brake. Fortunately none of that's hard to fix, provided parts are available. As for safety, you should get it fixed, it's safe to drive to a mechanic but not to live with.