That would be the brake "squealer" making that noise. It's telling you the brakes pads are worn down and in need of attention.
The rear brakes of the Caravan are adjusted automatically. Each time you set the emergency brake slack will be taken up. You can speed up this readjustment while parked, engine off, by "pumping" the emergency brake while pulling out the brake release. Adjustment may take some time as the slack takeup is small with each use of the emergency brake. A good habit is to use the emergency brake at least twice a day to avoid a low parking brake pedal.
When you install new brake cylinders they will have to be fully compressed in order to allow you to put them back onto the rotor complete with brake pads. After having bled the brake system, it is necessary to pump the brake pedal several times until a good amount of resistance is felt on the pedal (a firm pedal, not a squishy one) in order to extend the cylinders to the operational position. This is normal, and should not be taken as an indication that you've done something wrong. If you never get a firm pedal, or if the pedal still feels squishy even after extensive pumping you may still have an air bubble or leak somewhere in the system.
On most cars, you have to have your foot on the brake to be able to shift out of park while the car is running. Look to see if there is a switch connected to the brake pedal/brake pedal assembly somewhere that may have become dislodged and is not making contact. Some cars have a finger-operated switch that allows the driver to bypass the brake pedal switch and allow the car to be taken out of park without the brake pedal being engaged. If this helps, please 'Recommend Contributor'
Brake calipers are what house the brake pads and fit over the rotor. If you are working on the brakes, usually the calipers need to be taken off in order to work.
More than likely a small spring broke in the e-brake pedal assembly. The assembly is not designed to be taken apart and fixed. You will need to replace the assembly with a new one from the dealer or a used one from a wrecking yard.
Even though the brakes were recently changed, I would have the brakes taken apart and inspected. Something may have gone wrong.
You have to adjust the rear brakes, after you adjust the rear brakes the slack will almost be gone and you'll find the brake lever will grab almost at once. The cable going to the brake lever can be adjusted with a 10mm socket, but adjust your rear brakes first, the remaining slack then will be taken out by tightening the cable.This adjustment is located under the rubber cover, covering the bottom of the brake lever.
If front brakes are working properly - no frozen caliper or restricted brake lines with proper fluid flow to caliper - try check rear brake and parking adjustments to make sure they are not dragging and operating
If you brake system seems spongy, it most likely air in your brake fluid. To remove this simply jack up your Jimmy and proceed to remove the front wheels. After this has been done, and your tires have been properly removed, it is time to change your brake fluid. Buy the proper brake fluid and have a suction-pump or a friend at hand. The brake fluid cap is located under the hood. Remove this cap. If you fluid is a clear liquid, or is just turning a slight brown, then your fluid is good. If your fluid is black and groggy then it is time for a change. Proceed to pump out the brake fluid. If you do not have a pump, (which can be made homemade), then have a friend to sit behind the wheel. There should be a valve on the side of your brake system that allows you to drain your fluid. DO NOT EVER open this valve without the brake pedal being pressed. Air pockets form in your brakes and if not done properly, your brakes could fail. Making sure your buddy has the pedal pressed firmly to the floor, open the valve until the fluid looses its pressure. Tighten the valve. Pump the brakes for pressure, then hold to the floor. Repeat until the fluid is a clear color. Make sure that your brake fluid does not run out or you will have to inject it manually, which can be a pain. Having your brake fluid flushed is about $60-$100 in a shop, when you could just as easily do it yourself. Make sure the fluid is flushed when needed. If it is not properly taken care of, your brakes collect moisture which forms rust which could result in internal damage.
You can try pressing on the brake pedal as some cars require this before they can be taken out of Park. Otherwise, you may have a malfunction that requires a mechanic to fix.
Happened to me once when I changed exhaust in my car- hot exhaust near brake line expanded fluid, locked up brakes. Another thing comes to mind, drum brake master cylinder on disc brake car, did you replace master cylinder before having problem? Any time a brake friction component comes into contact with a braking surface, heat is generated. If the shoe or pad generating that heat is not removed from contact with the drum or rotor for an adequate period of time between applications, heat is built up to an excessive level. This creates both a glaze upon the contact surfaces and a boiling condition of the fluid within the brake cylinder or caliper. This boiling increases the pressure exerted upon the braking surfaces further, leading to brake lockup; and, should the brakes be applied, the glazing which has occurred prevents normal friction action from slowing the vehicle as intended. This condition results in more pressure being applied to the service brake pedal in an effort to control the vehicle, which creates yet more heat, and more pressure inside the system. What is felt at the brake pedal is increased resistance due to these factors. This is the 'hard pedal' associated with the condition of 'brake fade'. If a caliper is sticking on its slides, or a brake shoe is adjusted too tightly, the result will be as depicted above. In addition; should the master cylinder be overfilled, not allowing for the expansion of the brake fluid when hot, this can occur. Brake fluid which has absorbed an excess of water will also cause this, due to the lowering of its boiling point by that water; and, since it is hygroscopic, brake fluid can absorb as much as 3% water by volume in a sealed plastic sales bottle in a year's time just through the pores in the plastic. Taken together, these things make it all too clear what can happen when brake systems are left without maintenance monitoring; and, if your car is "right", the car of the guy coming toward you may be faulty in this regard. Be safe; keep a professional eye on the brakes: A short-cut here is a short-cut nobody should take...
Brake warning lights need to be taken very seriously - it could mean, as you say, that your brakes need to be renewed. You should not drive the car until you have it checked by an authorized dealer - it could mean your brakes are about to fail or may not work properly, especially if used in an emergency situation. Driving in this state is risking your life and the lives of other road-users.