Easiest way to see the level is to put a small light directly on top of the reservoir with the light shining into the reservoir. The opaque material of the reservoir can make it very hard to see the level without a light.

As brakes wear down your fluid will drop in level a bit as an fyi. Dont panic no need to top off.

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Use a bright flashlight. You might have to shine the light BEHIND to get a better idea of the level.

It could be a clogged brake line somewhere, I'd go ahead and bleed your brakes (there's videos on YouTube for this), and see if any of the bleed valves have extra air/dont let out brake fluid. Could be your problem, you'd need new brake lines at that point. (I've done this like four times on my cobalt, it's fairly simple & cheap, especially if you're able to figure out which line & replace just that one.) It could also maybe be your brake master cylinder failing to cycle brake fluid through all of your brake lines. But to me, from what you've listed as issues I would start with bleeding your brakes to see if you can find a blockage somewhere.

I’m with the other guy, definitely bleed the brakes, and if they have been squealing since you put them on, check to see if your brake caliper is seized. Mine didn’t squeal but it was like a metallic rubbing noise. My brake pads didn’t release all the way with the caliper, also did you only replace the front? The rear drums also have a tendency to squeal pretty bad as well, depending on mileage and road conditions. I lived on a dirt road and they got abused regularly, a pot hole ended the life of one of my drum brakes due to the force.

Also, YouTube YouTube YouTube, these cars have so many videos on them in my opinion, can almost find anything. For repairs I like 1A auto but they don’t cover everything.

If your fluid is below minimum, add fluid and see if light goes out. That brake light might also be used to indicate your parking brake is on.

Do you have a mechanic you trust? Or a friend who is actually knowledgeable about working on cars?

The brake fluid has to have gone somewhere. I imagine there must be a leak in the system, or somehow the fluid wasn't topped up when the brakes were last serviced.

Make it a habit of checking brake fluid levels maybe every other gas fill up when you are in the engine bay checking your engine oil and coolant levels.

Get yourself a bottle of DOT4 brake fluid and fill the reservoir back up to the full line. Having the fluid too low will introduce bubbles and may stop your brakes from working entirely.

As for the squealing, an inspection of each wheel is in order with that corner of the car jacked up securely.

Hi! Idk how to edit the post but updateeee. Took it to the shop and they flushed the breaks and topped up the break fluid and she’s running like a champ, thank you everyone for your comments!!!

Basically, the multimeter is measuring the presence of water. This is also how those specialty brake fluid testers work.

If the brake fluid is still good, all you'll need to do is top up and you're fine. If the brake fluid has begun to go bad, its good to know this early on because the solution, if caught early can be as simple as a fluid replacement, instead of a costly fluid system flush.

Dude why does this even matter lol, a huge bottle of brake fluid is 6$ at autozone. You should flush your brakes when you do a brake pad replacement. Brake fluid is designed to absorb water, it just lowers the boiling point, which in almost every case bar high performance cars it doesn’t make any significant performance difference.

Could you test your fuel for moisture content by using a multimeter?

How

The level is right below the word MAX, which is fine. The brake fluid should only be at the MAX line if you have just installed brand-new pads and rotors on all four wheels. As the brake parts wear, more fluid is needed to make everything touch and slow you down. That’s normal. You don’t need to add fluid at this time.

The color looks reasonable. It starts out clear and yellows as it ages. The fluid picks up moisture from the air, especially if the cap isn’t tight. Moisture ages the fluid and makes it work more poorly. Generally it should be replaced every three years as it will pick up too much moisture to work well by that age. If it looks brown, it’s way overdue or your brakes are badly overheating.

It’s easier to check if you hold a light on the far side of the reservoir. The light makes the fluid easier to see.

That is most definitely a kia **BRAKE** reservoir.

I just shine a flash light to better see the level. Yours looks fine. Do flush it periodically - every 3-4 years, regardless of mileage. The red filter piece does not come out (easily). I use a motive power bleeder to do mine. Makes it a one person job. In the stinger without brembo's, 1 32oz bottle was enough to do all 4 calipers.

The fluid appears to be right about at the bottom of the word "MAX".

Put a flashlight on container to light it up

There's a big gap between Max and Min so fill to where you think is near the max and you'll be fine. From the photo it looks like you are perfect where it is.

Flush. When brake fluid becomes dark it is time to change. It breaks down over time.

Flush it anyways, not bad to do it every 3 years. Coloration does not tell you everything. Most oems recommend it every 3 years. Brake fluid loves water and moisture and likes to rust your shit from the inside out.

Thank you all very much. I learned a lot from everyone's responses. I will definitely check the brake pad and will also do a flush since it's been awhile. Good to know about not just topping it off.

As long as you don't hear any grinding, just top it off. A flush is just a scam from the dealership to suck some more money out of your pockets. 400k on my old chevy, never a flush, never a problem.

Check your brakes, if they are under 3mm swap the pads and rotors, and since you have the tires off, flush the brake fluid

Are you asking how to check the reservoir? Or the caliper’s? Brake fluid starts out clear and will darken over time. There is a service interval recommended in the users manual for your specific model.

Brake fluid is hygroscopic (absorbs atmospheric moisture over time), this is bad for a number of reasons (corrosion, ice-locking in the lines in freezing temperatures - can prevent brake application, etc..), so it is important to replace it as recommended by the service manual (usually every 2 years/ 40,000km).

Just do it based on the service interval and you'll be fine. If not to at least crack the bleeders open so they don't get seized.

Hint, don't do this on an old car unless you're prepared and ready to replace calipers lol

When i changed mine the fist time i LOOKED okay in the resevoir But when i bled the lines rusty muddy brake fluid came out. Definitely do it.

It's not just the color you need to check. It's the amount of water in the brake fluid like these. Brake fluid absorbs moisture when open to the atmosphere.

Phoenix Systems 8006-B Double-Ended Coolant + Brake Fluid Test Strips (15 foil wrapped test strips), 1 Pack https://a.co/d/9RnFd1U

Brake fluid goes bad because it accumulates water over time. While color and level are important, you cant look at brake fluid and know if its bad. You need to test it to measure the water content.

Looks fine. Mine turned from clear to this color in 5000 miles.

There should be min and max marks on the side of the reservoir. If anything that looks a little high.

Color looks ok. A little darker than I would expect for 20k miles but at that point you’re about halfway through the typical lifespan of a normal synthetic fluid.

I don’t see anything here that needs to be urgently addressed but you want to avoid having the cap off/loose. Take another pic at your next maintenance interval and compare.

It can wait but it's surprisingly dark for only 3 years / 20k miles. Humid area. Okay.

Keep an eye on it, maybe do it next year.

Shit. Mine looks like used oil. I better change ASAP

The leak may very well be out the backside of your master cylinder INTO your brake booster. Unbolt the master and pull it forward just a little bit... does brake fluid run out? Or can you dip the end of a ty-wrap in and see if there is brake fluid on the end... There shouldn't be.

But then again, the ABS unit, if you have one, might be leaking from a position that doesn't make the leak obvious.

Some cars and truck are more likely to have this problem than others but you didn't bother to tell us... So Good Luck with your diagnosis.

Probably the brake booster. There's probably a vacuum tube coming out of it in the engine bay you can pull out and check for wetness. You can also check the firewall for brake fluid inside the cabin where your feet go

This dude may be on to something. I’ve had master cylinders leak into the booster causing mysterious brake fluid loss before. Stick a zip tie down the vacuum port in the booster and see if it comes out wet. If so, there’s your problem.

Youndid not post the make model and year of car. it matters.

Brake system are a closed system, meaning that you should never have to add fluid.  In a good system, low fluid indicates that the wear surfaces (pads/shoes) are worn down and need to be replaced.  

The fluid has left the reservoir to take up the space of the worn components in the caliper pistons or wheel cylinders. Replace the wear surfaces. 

The Pistons get pushed back and the fluid level and the reservoir goes back up. 

If this isn't the case, then you definitely have a leak and sometimes it can be tricky, especially on rear wheel cylinders where the dust and dirt can absorb the fluid of a slow leak making it difficult to spot.