A loose belt. Most likely the alternator belt, if it doesn't squeal when you make a sharp turn.
sometimes if the brakes are old
That depends on how, when and where it is squealing. For example, if the brakes squeal when applied, the brake pads are probably worn down. A squeal from the engine compartment whenever the engine is running could be a loose serpentine belt (especially if the squeal changes a little when you rev the engine).
When your tires squeal at a low speed it can mean a number of things. The tread on your tires may be almost gone or you may have low tire pressure.
No. Low tire pressure causes poor handling and poor tire wear.
You Dont Grease It Up enough
It can be several things, either by themselves, or in combination. 1) the belt has dried up and isn't as grippy any more. This causes it to slip and squeal. There are sprays available to restore grip on belts which might help. 2) the belt has stretched a little, which causes it to slip and squeal. Retension, usually by adjusting the alternator position and it should be OK. 3) one of the auxilliaries(alternator, power steering pump, water pump) is about to seize. If it's harder to rotate the belt will slip and squeal.
Pads worn out. Dust between pad and rotor. Leading edge of pad has 'feathered' and needs filing off. Pads fitted without anti-squeal shims.
I had this problem on two separate occasions. The first time it was because the big-O tires had put the wrong size tire on my car and it was rubbing. The second time it was because my CV (sp?) joint went out.
try checking the battery
Out of balance, bent wheel, defect in tire.
the right because it is getting the full weight of centrifugal force on it it will tend to slip hence the squeal