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Will Car Brakes Work Without Fluid? (This is important)

Hydraulic brakes

Having your car break down is a pain but having your car brakes go out is a terrifying experience. Brakes are mission-critical kit and must be kept in good condition.

A car’s foot brake is a hydraulic system and will not work without brake fluid. The parking brake or E brake is a separate brake system and will work without brake fluid. The parking brake, however, is not a reliable source of braking.

In this post you’ll learn why your car brakes won’t work without fluid, you’ll also learn the most common brake problems and what you can do to fix them.

Hydraulic Brakes

Top up brake fluid

Hydraulic brakes have been adopted by all car manufacturers since the 1950s. Prior to that, brakes were cable-activated, very similar to bicycle brakes.

Hydraulic brakes are common for good reason, they have some really huge advantages over cable-operated brakes. The hydraulic brake is like a force multiplier, a little force at the foot pedal equals a force much greater at the wheels.

Old cars were heavy so good brakes were very useful when trying to pull up a couple of tons of metal in a hurry.

The hydraulic system is safer, more consistent, reliable, and not prone to complete failure. All great things when you’re talking about parachutes and brakes, right!

Pascals Law

The laws of hydraulic – discovered by French mathematician Blaise Pascal in 1647. He discovered when pressure is applied to any part of a liquid in an enclosed system, the force will be transmitted equally in all directions.

So what does that mean?

It means our foot pedal force is multiplied many times at the brake caliper. If we had to rely on our own leg strength to pull a car up, we’d find it close to impossible.

Pascal discovered by reducing the size of the master cylinder and increasing the size of the brake caliper cylinder, he could multiply force.

All of this of course would be impossible without a noncompressible fluid-like brake fluid.

No Fluid Equals No Brakes

As you push your brake pedal, force is applied to the brake fluid inside the master cylinder. The force on the fluid is transmitted through the brake lines to the calipers or drums.

Pads and caliper

The caliper or drum houses a piston and also the brake pads. The pads are positioned against the spinning wheel rotor. The force on the fluid acts immediately to displace the caliper piston, which in turn pushes the pads forcefully against the spinning wheel rotor, slowing the car down.

The Parking Brake

Parking brake sensor

The parking brake or E-brake (Emergency) is designed as a second brake source, independent of the hydraulic system. The parking brake allows you to apply a vehicle brake without manually holding it. Makes good sense when hill parking.

The brake was also conceived as a backup brake should all the hydraulics go out. While it is possible to use the e brake as a braking source, it will be pretty ineffective and actually dangerous.

The reason is simple, the e brake tends to be a blunt tool, the application of the brake won’t be smooth like your foot brake. Very often pulling the e brake while driving will simply lock up the wheels.

In addition, the e brake only brakes two wheels, the rear and if the roads are wet, icy, or surface loose, it will cause the car to swap ends in heartbeat.

No Brakes

Holding down brake pedal

Brakes going out thankfully isn’t very common. Car brakes are usually very reliable, but like all systems, have their weakness.

Here’s a list of the causes of no brakes, and what you can do to fix them:

  • Pads worn out – Replace.
  • Brake fluid leak – Replace brake lines and flexi hoses.
  • Air in the system – Replace fluid and check unions for leaks.
  • Incompatible brake fluids – Flush the system and replace fluid.
  • Master cylinder failure – Replace.
  • Brake booster failure – Replace.
  • Brake caliper or cylinder failure – Replace.
Brake inspection chart

Common Brake Complaints

Brake fluid

Brake system complaints are common, but rarely very serious. Here are the most common problems:

  • Brake noise – Remove the pads and replace them or de-glaze them. Clean the brake carrier and use Moly or Graphite dry grease on the pad arms and backs.
  • Brake pedal pulsing or vibration – Check your rotor run-out, and wheel bearings. Buckled rotors are the more common cause.
  • Steering vibration under breaking – Check wheel bearings and ball-joints before checking rotor run-out.
  • Dragging brake – Remove caliper and check for frozen pins or seized caliper.
  • Seized brake – Replace caliper.
  • Soft brake pedal – Replace fluid.
  • Hard pedal – Check brake booster and vacuum hose.
  • Pedal fade – Bleed brakes and check booster operation.
  • ABS light on – Scan ABS control module for fault codes.

If you are undertaking your own brake repairs, you’ll need tools, check out the “Brake repair tools page” and check out the Amazon link below for quality brake system parts.

Amazon Brake Parts

Related Questions

Can you just add brake fluid to your car? You can simply top up your brake fluid so long as the fluid level is not below the Min level. However, a low brake fluid level is commonly caused, not by insufficient brake fluid but instead, by worn brake pads. Replacing the pads will return the fluid to the full position.