Q: Brake pedal slowly becomes firm to press after short period of driving

asked by on

I had an issue with one of my rear rotors / pads, so I replaced both rear pads and rotors. I plan to do the front ones tomorrow, but i'm having an issue with the pressure building up in the brake system. The brake pedal gets firm / hard to press down after maybe 5-10 minutes of driving. When this happens it feels like the brakes are constantly being applied, and I will have to press the pedal down pretty hard to be able to shift into reverse. If the car sits parked for awhile the pressure slowly goes back to normal. My initial research tells me that this could be due to a bad / damaged flex hose. Not sure if bleeding the lines / air in the system could possibly cause too much pressure as opposed to too little. I will bleed the system when i'm doing the front brakes tomorrow anyways, but just looking for some input with this problem.

My car has 116000 miles.
My car has an automatic transmission.

Hello and thank you for your question.
The problem lies within the proportioning valve in the brake system. The valve could be plugged up with debris in the system making the valve stick. If the proportioning valve is okay and working correctly, then the brake controller plungers has some debris in the system. I suggest getting two large bottles of brake fluid Dot 3 and flushing out the entire system with all new brake fluid. This will help remove any debris in the system and help keep the system clean. If the system is still being pressurized after flushing out the entire brake system, then you may have to replace the proportioning valve or brake controller to keep the system from building up. If you need assistance with diagnosing your brake system, then seek out a professional, preferably a professional from Your Mechanic to help you with your brake system.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Brake pedal slowly becomes firm to press after short period of driving

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Ac compressor leak

A/C leak sealant is only good if you have a rubber seal that is dry and hard and a sealer that is designed to soften the seals. It may help, but in most cases it will not seal a compressor...

Q: 2007 galant es blower motor resistor or transistor

Your vehicle is equipped with a blower motor resistor block. It is a modular, replaceable assembly and the part is different for Galants with and without A/C systems. If your blower motor is not functioning, failure of the resistor block...

Q: My alarm is randomly going off

There are numerous reasons this may be happening. However, there is a technical service bulletin (TSB) #09-BE-026 pertaining to alarm system self activation due to a defective hood switch pad. The TSB states: The vehicle alarm system may intermittently...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...