What is The Purpose of Bleeding the Brakes in My Honda Accord or Any Car?

Reader Question Hi Austin,
I came across your webpage while searching the Internet to find out why one needs to bleed the brakes.

I have a 2003 Honda Accord (with ABS) and I have been having this one issue for a while now and I have not had any luck with any of the mechanics (including the dealer). Problem is when I step on the break pedal, break does not respond to first inch or so – the pedal feels really soft. Then after that the it break really hard and suddenly.

I was thinking that there might be some air/moisture in the break line and maybe thats what is causing the problem – if thats what water and moisture do?

I have other cars and I brake very smootly on other cars but on this car I have never been able to get use to this car’s breaks. Even the passengers complain that I am break too hard.

I am not sure if I have explained the problem clearly or not as I am not too good at explaining things 🙂

Any feedback from you would be greatly appreciated.

With best regards,
-uday

Hello Uday,

Thanks for your email. I have seen/felt this complaint before on an Acura at my shop. The problem with that car was the brake master cylinder was faulty, we replaced it and the problem went away. I have also seen a similar complaint with a Chevrolet truck, and we replaced the two front brake calipers and brake hoses, and the problem went away.

Air can become trapped in the brake system, but it can really only get in there if there is a brake fluid leak somewhere…you would be loosing fluid, and eventually the brakes would stop working all together. Or after your last brake job the mechanic did not “bleed” the brakes properly…but that would mean the problem would have shown up right then.

Bleeding the brake system is just letting air, that was introduced when the brake system was worked on, out of the system. There are bleeder screws on each wheel that allow the mechanic to open up and allow the brake fluid to drain out…pushing out the air.

Air in a brake system usually makes the brake pedal very low, you really have to push the pedal down a long way before the brakes begin to work. This happens because you have to push the air out of the way of the brake fluid before the brakes work. I don’t think that is the complaint you have.

I would first start by inspecting all four brakes, and make sure all the brake pads and shoes look ok. If things look ok, I would replace the brake master cylinder. The brake master cylinder on this car is pretty inexpensive, and if this problem really bothers you, I would take a guess and replace the master cylinder.

Keep me posted.

Blessings,
Austin C. Davis

Follow Up
Hi Austin,

Thank you VERY MUCH for replying to my email and the time you took to explain the different scenerios in so much detail.

Though I did not do a good job of explaining, You nailed the problem exactly when you wrote “Air in a brake system usually makes the brake pedal very low, you really have to push the pedal down a long way before the brakes begin to work.” because that is what I was trying to describe.

Taking your advice I inspected all 4 breaks (pads etc) and they all looked fine. Then I replaced the break fluid and bled the system and since then the breaks have been like “normal” breaks – smoother and predictable.

I REALY want to THANK YOU for your help.

If you ever have ANY computer related question please feel free to contact me and I will do my best to help you out.

With best regards,
-uday