Why Does My Brake Pedal Go To The Floor?

When you begin to feel like your brake pedal is soft, spongy, or drops to the floor when braking, there are a few components to pay attention to. Any one of these parts could be the source of the problem:

Front disk/drum assembly
Master cylinder
Brake lines/ hoses
The brake pedal
Rear disk/drum assembly

Before you start digging into these components, bear in mind that auto brake systems are vacuum-based systems. In other words, to work right these systems must be sealed against ambient air.

How To Check For Source Of Soft Brake Pedal

Step 1 – Investigate The Master Cylinder Reservoir

Look for a low level of brake fluid or drips and leaks in/around the reservoir.

Step 2 – Check Lines/Hoses

If the reservoir looks ok, get under the vehicle and look for signs of puddles. In this case, there could be an issue with lines/hoses or fittings. If there is, check out this article.

Step 3 – Inspect Sealed System

You want to investigate the stability of the sealed system because air-leakage could come from any component within the system including fittings and connectors. If you pump the pedal and brake tension increases, this is a tell-tale hallmark of air leakage.

Step 4 – Look At The Master Cylinder

If all of those focus areas fail, it is likely that the Master Cylinder is at fault.

Step 5 – Pay Attention To Slave Cylinders

If the master cylinder appears ok, next look at the slave cylinders. Vehicles use individual slave units at each wheel, which creates back pressure in the overall system.

Step 6 – Say ‘No’ To Brittle Hoses

Check for leakage associated with any brake booster unit, including any affiliate hose components. In this case, brittle rubber due to extended heat-cycles can be a cause.

Were you able to find the cause of your soft brake pedal? If not, give us a call. We’d be happy to give you more guidance.