Hey guys,

I recently put a fresh battery into my 93 Accord. It's been without a fresh battery for a while and so I finally put on in. The car starts up fine like it always did except now the light that says BRAKE is on as soon as the car is started up and every minute thereafter.

The car is virtually unchanged since the battery went dead, the only thing that was replaced was the battery so I have no idea why this light is on. A family member drove it (I have yet to drive it, have to check today) and they said the brakes felt weird. No idea if they're just imagining things or not.

I'll go check the fluid level today but I thought this light was reserved for the parking brake. We attempted to lower and raise the parking brake repeatedly to see if maybe it was a stuck sensor, no dice. It's also extremely cold here these days since I'm in the north east.

To be clear this is the light to the left of the SRS light on the dash that says "BRAKE" on it. It is not the light on the car diagram.

 

The same lamp that comes on with the handbrake?

Check the brake fluid level. If it's actually low, then bleed your brakes. That's because you said the brakes "felt weird".

Maybe the brake pads are wearing out, causing the fluid level to be low in the reservoir. Check how much material is on your brake pads.

 

Yes. The one that says "BRAKE" in letters that's a box shape.

I didn't check the fluid level yet, going out to go do that now. The "weird feeling" might just be subjective since it was a family member driving and they might not know how the brakes feel.

But why would the pads and fluid be low if the car wasn't driven? Does this stuff evaporate or something? I thought it always stayed constant.

 

What do you mean the car wasn't driven? It's only a coincidence that the brakes are getting worn out just now. Not related to the battery replacement.

As the brake pads wear out, the caliper pistons extend further and further out, which takes fluid from the reservoir down to the calipers. The size of the reservoir is chosen based on how much fluid has to be stored to handle this.

You repeatedly worked the handbrake lever, but also check the little button switch below it. It's possible that it just got bent away or corroded or something.

It's also possible that the float-switch in the brake fluid reservoir is the culprit. Check that out if you find that the fluid level is OK.

 

I didn't get to check the physical brake components but I checked the fluid. I'll go check the float tomorrow. The fluid level seemed fine.

I mean it literally when I say the car was not driven since the battery died. This is what I mean: the car was fine, no funny brake feeling no brake light and then the battery died one cold morning. Then the battery was replaced yesterday and the car was started up and the brake light was on. The car was not driven while the battery was dead. The only thing that has occurred since time when brake light was off and when the brake light was on was a car that wasn't driven because of a dead battery, it just sat there. So I have no idea why the light would be on then because the brakes weren't even touched because the battery was dead.

I thought it might be some kind of brake "code" if that even exists, maybe because the battery was dead it reset something?

 

There are no codes for the brake light.

The two likely causes are the e-brake switch under the center console. Or the brake fluid reservoir level switch.

Try unplugging the two connectors to the brake master cylinder cap. If the light turns off, then there is something up with the float in the master cylinder.

 

An update: Apparently even though the fluid seemed fine, it was not. I put fluid in up to near MAX line and the light went out. Problem solved.

But the issue now is soft brakes, it was not this soft before the battery died.

The brakes go all the way down and the car does not stop on a dime. It's an unreliable feeling. It doesn't sink to the floor extremely fast with no pressure like the master cylinder issue, it's also very cold out. It travels downward with some pressure but doesn't stop fast or strongly.

Does it seem like a master cylinder issue? Or brake pads? I don't hear squeaking so I ruled out the pads. I checked for leaks at the master cylinder and brake booster and found none. Every time I push down on the brakes I can hear what sounds like air coming from where the pedal is. Especially when I jam on it multiple times in a row repeatedly to see if I could build up pressure.

 

Check all of the lines for leaks.

Car on, push the brake with "somewhat" firm pressure and try to hold, does the pedal "sink" to the floor?

 

Where are the lines? The ones running out of the master cylinder or are there more? I checked the ones running out of the cylinder and saw no leaks. Can I check for leaks by having someone push the breaks while I check inside the reservoir for air bubbles popping up?

I tried this, this does not occur. I would believe that if it did it would signal a master cylinder issue since I've experienced this first hand on another Honda I have with a worn master cylinder. On hot days with that car the pedal would travel all the way to the floor and then when it hits the bottom it sinks further in with no pressure at all kind of like the pedal is going into a swamp.

This definitely does not occur on this car that's experiencing soft brakes.

 

You might want to bleed the brakes and get fresh fluid in there. If the fluid was low enough, you could have pulled air into the system.

Just use a turkey baster to remove the fluid from the master cylinder reservoir.

Then go from wheel to wheel bleeding at each caliper until the fluid is clear. The bleeding order is rear passenger, rear driver, front passenger, then front driver caliper.

If the bleeders are rusty, soak them in penetrating oil like pb blaster, because the bleeder bolts can be sheared if you use too much force on them (guess how I know?).

It might be a good time to grease the sliding pins. Use silicone paste and not grease. Those little caliper grease packets at the counter of most parts stores are silicone paste (I think).

In the end, your problem could end up being the master cylinder.

A bottle of brake fluid is less than $10 and may be worth a shot.