Why my car's brake is hard?


On an evening a couple of weeks ago, I had to drive my car (2002 Honda Accord v4)over a very icy area, but just for a few minutes. In the morning next day, my brake was very hard to push and it did not work properly (takes much longer to stop). I immediately had the car checked at a shop and they told me to replace the brake booster. So I told them to do that but my car still has the same problem these days. However, only on very cold mornings when I first start driving. After half our driving, the brake works fine. I did some research online and it seems that the brake fluid might need to be changed. So I went to the same shop and asked them if my brake’s problem is really the brake fluid, not the brake booster. They checked my brake fluid but said they can’t tell for sure because they filled the reservoir the other day when they were replacing the brake booster. My question is: is that possible the old brake booster was fine and I just need change the brake fluid? Why they did not think of checking the fluid in the first place? Is that logic to think a bad brake booster is the only reason for a hard brake (they did say they checked the pads and they are fine)? Thank you very much.

First thing I’d do is replace the brake fluid. Brake fluid can absorb moisture. What may be happening is there’s enough moisture in the line that it’s actually freezing on cold mornings and it’s causing this problem.

It’s likely that the brake booster was fine and the “shop” that you are using is not good at diagnosing problems.
I suppose it might be too much water in the brake fluid (when was it last changed?), but it could be the caliper slides or some other issue.

I agree with Mike.

As to why the shop did not change the brake fluid, you would have to ask them, but my guess is that uninformed car owners may have accused them of “gouging” them when they did do brake fluid changes.

Unfortunately, a lot of car owners will accuse a shop of gouging for anything other than very basic repairs. Sometimes mechanics will skip items that they would like to do, rather than argue with irate customers who don’t actually know anything about car repair.

Make mine another vote for the brake fluid, for exactly the reason Mike mentioned.

The part that always saddens me about posts like this is that the booster is so easy to check. Simply push the pedal repeatedly with the engine off until it hardens, then, while pushing the pedal, turn the engine on. You’ll feel the pedal soften.

Add me to the list of people saying to have the fluid replaced.

An alternate thought.

Maybe the check valve is freezing up. If the booster gets no vacuum, it will not work to assist the brakes. Once the engine heat thaws the check valve, the system works fine.