Skip the auto shop - Our mechanics make house calls

Q: Brake lines have air, bled many times

asked by on

My truck constantly gets air in the brake lines. They have been bled multiple times but the issue reoccurs. I had the master cylinder replaced. The system is pressure tested as well. There are no leaks. What might be wrong?

A: Hello. Moisture in the brake fluid is being...

Hello. Moisture in the brake fluid is being boiled off as steam when your brake system temperature gets above 212 degrees (at sea level). The steam re-condenses as water in the system BUT air pockets can be created and remain inside. You might need to bleed the system with new fluid quite a few times to be sure all moisture is removed. Be sure to keep fluid level in the reservoir is at "full" level when done.

Was this answer helpful?
Recommended services
Get a Quote

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: Leak in the braking system

Generally, that's the brake master cylinder, and when they leak, they leak into the booster. So what you might try to do is take the master cylinder off and see if the inside is wet. Take a flashlight and look...

Q: Doorlock and door opener broken

It sounds like the door latch needs to be removed and replaced. The door latch and locking mechanism are built into the same part and can easily be replaced. I would recommend having a technician from YourMechanic come out and...

Q: Car won't start there's an blue led light that blinks twice everytime i turn the key

Hi there: It's possible that your 1996 Honda Accord is experiencing an electrical relay problem in the ignition lock cylinder that might be causing the starting issues. The problem might also be caused by a drained battery or an alternator...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...