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?

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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Clutch not engaging

Hi there! It sounds like there may be a a little air left in the clutch hydraulic system. Air in clutch lines will cause the exact scenario you describe. The air will be moved to a different location in the...

Q: Air conditioner parts exchange - Will AC parts from a 1994 fit a 1989?

Just because both have the D21 motors you will still need to verify the mountings to the compressors are the same. The connections and hoses may all be different since body style and engine compartment has changed over the years....

Q: while in park it acts like its in gear what could cause this

Hey there. Most likely the shift linkage or cable is worn, which is causing the gear selected to not match what the transmission is in. I recommend having the shift linkage checked by a mechanic like one from to...

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...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.