No Brakes After Changing Pads? (Mechanics advice)


Foot to floor and heart rate through the roof…why aren’t we stopping. No brakes even at low speeds can be alarming. Changing brake pads isn’t a difficult job but it is important to follow correct procedures. In this post we’ll solve your problem.

No brakes after changing pads? The top two common causes of no brakes after changing brake pads include:

  1. Incorrect brake pad bed in procedure
  2. Air in the brake system

In this post you’ll learn the common causes of no brakes after pad change, you’ll learn how to diagnose your brake problem and how to fix it.

1 Incorrect Brake Pad Bed-in Procedure

New brake pads fitted

Brake pads ride close to the rotor ready to apply force at the touch of the pedal, new pads won’t naturally take up this position after a brake job, they need to be prepped. Part of the process of fitting the brake pads is as you know pushing back the caliper pistons. When the pistons are fully retracted they allow for the extra space needed for the new fatter brake pads.

As the caliper pistons are fully retracted, the excessive free-play between the new pad backing and the caliper piston must be removed. Failing to remove the gap will cause the brake pedal to sink to the floor with little or no brake capability.

In addition, the friction surface of the brake pads need to mate to the rotors and until they do, braking efficiency will be poor.

Lack of performing a proper break-in procedure is a cause of no brakes after replacing brake pads.

Bed-in Procedure

Pumping car brake pedal

Bedding in the brakes isn’t difficult and doesn’t require any tool or much effort. Follow the steps outlined below:

Pump brakes – pump brakes several times until the pedal is firm. This action closes the gap between the caliper piston and pads. Failing to close the piston to pad gap before driving is dangerous, the vehicle won’t have a brake pedal. The brakes still won’t feel right, but the pedal will be firm.

With a firm pedal, test drive the vehicle at low speeds about 30-50 mph and brake lightly, heavy braking risks overheating and damaging the brake pads. The brake pedal will begin to improve and after 5 to 6 applications the pedal will feel normal.

2 Air In The Brake Lines

opening brake bleed nipple

Some brake pad fitting techniques may instruct opening of the bleed nipple when retracting the piston. This technique prevents potentially contaminated fluid moving into the master cylinder and requires bleeding the system after wards.

If the hydraulic system is opened, it must be bled. Air in the system will cause a low pedal with little or no bite.

Brake Bleeding Procedure

There are several different ways to bleed your brake system, but by far the easiest and most reliable is the vacuum brake bleeding tool. This is a one man job and requires only a basic bleed kit.

Proceed as follows:

  • Remove the reservoir cap, set aside and fill the reservoir to the very top with brake fluid.
  • Bleed the wheel farthest from the reservoir and finish with the wheel closest.
  • Clean the bleed nipple, fit the bleed kit pipe and open the bleed nipple.
  • Apply vacuum and bleed until no further air is seen in the pipe, check and top up reservoir regularly.
  • Repeat on all brake calipers/cylinders.
bRAKE FLUID CHART

Related Question

Can I drive on grinding brakes? Grinding brakes are caused by worn brake pads or debris trapped between the rotor and caliper. Driving on grinding brakes is a safety hazard. Brake performance is reduced and brake components such as rotors and calipers will be damaged.

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of classic car ownership, from tires to roof aerials and everything in between.

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