* Low Brake Fluid: This is the simplest and most likely cause. Check your brake fluid reservoir (usually a clear plastic container near the master cylinder) – if it's low, you need to add fluid *immediately*. However, simply adding fluid is only a temporary fix; you need to find the *source* of the leak. Low fluid points to a leak somewhere in the system (wheel cylinders, calipers, lines, master cylinder).
* Leaking Master Cylinder: The master cylinder is the heart of your braking system. A leak here will drastically reduce pressure, leading to a hard pedal. This often manifests as low brake fluid as well.
* Leaking Wheel Cylinders or Caliper Pistons: These are located at each wheel. Leaks here will cause fluid loss and a spongy or hard pedal depending on the severity.
* Leaking Brake Lines or Hoses: Corrosion or damage to the brake lines or hoses can lead to fluid leaks and a hard pedal. Inspect them carefully for any signs of rust, bulging, or cracks.
* Air in the Brake Lines: Air in the brake lines will compress, preventing proper pressure buildup. This usually results in a spongy pedal, but a significant air leak can lead to a hard pedal.
* Faulty Brake Booster: The brake booster uses engine vacuum to assist in braking. A malfunctioning booster will make the pedal feel very hard, requiring much more effort to stop the vehicle. This is less common than fluid leaks.
* Restricted Brake Lines: Extremely rare, but heavily corroded or clogged brake lines could restrict fluid flow.
What to do:
1. Safety First: If your brake pedal is hard, drive the vehicle as little as possible and only when absolutely necessary. The brakes may fail completely.
2. Check Brake Fluid: Inspect the fluid level in the reservoir. If it's low, *carefully* add DOT 3 brake fluid (the type specified for your Caravan in your owner's manual). Do *not* overfill. Adding fluid does not solve the problem, only addresses the symptom.
3. Inspect for Leaks: Carefully examine all brake lines, hoses, calipers, and wheel cylinders for leaks. Look for wet spots, stains, or dripping fluid.
4. Professional Help: Unless you're very experienced with brake systems, it's crucial to take your Caravan to a qualified mechanic to diagnose and repair the problem. Brake failure can be dangerous, so don't attempt major repairs yourself unless you're qualified.
A hard pedal indicates a serious problem. Don't drive the vehicle until the problem is addressed by a professional.
