How To Change And Add Brake Fluid In Your 2015 Chrysler 300: A Step-by-Step Guide

Last Updated on 2025-10-13

Hello mate, it seems today you're doing some car maintenance work yourself. Sure, adding brake fluid might not be the most fun task. Still, it’s one of those little things that can keep you from a world of pain farther down the road. So, let’s get our hands dirty and do this right.

Why Brake Fluid Matters

So, here’s the thing—brake fluid is what actually makes your brakes work. The fluid transfers the pressure from the pedal to the brake calipers, which squeeze the rotors to slow down the car. Dirty or low brake fluid will cause your brakes to underperform. You definitely want to be aware of this before you’re cruising downhill.

Aside from that, brake fluid also absorbs moisture over time, which can negatively impact braking performance. So regularly checking and topping it off is essential.

How to Check If Your Chrysler 300 Needs Brake Fluid

Before we start pouring anything, let’s make sure your car actually needs more fluid:

Park on a level surface – Keep things steady so you get an accurate reading.
Pop the hood – The brake fluid reservoir is on the driver's side near the back of the engine bay.
Check the level – The reservoir is see-through with "MIN" and "MAX" lines. If it's close to or below "MIN," it's time to add more.
Check the color – Fresh brake fluid is almost clear or light yellow. If it’s dark brown or black, it’s time for a full flush, not just a top-up.

Finding the Brake Fluid Reservoir

Alright, let’s try to find that reservoir. Lift the hood and check around the driver’s side firewall. There should be a small container which says "Brake Fluid" or some kind of brake symbol (a circle with brackets). That is the item we are dealing with.

If you can’t find it, try turning on the flashlight on your phone; it makes a difference.

Cleaning Before Opening

Before you twist that cap, take a second to wipe it down with a clean rag. Brake systems are picky about dirt, and even a little bit of gunk getting inside can cause issues. Don’t use compressed air to blow off dust—just a clean rag will do the trick.

Adding the Brake Fluid

Alright, time to get to work. Chrysler 300s take DOT 3 brake fluid, so make sure you have the right stuff. Here’s how to do it:

Slowly open the cap – No need to rush. Just twist it off carefully.
Check the fill lines – Shine a light if you have to, but don’t overfill.
Pour in DOT 3 fluid – Add just enough to bring it up to the "MAX" line. Overfilling isn’t a good idea because brake fluid expands when it gets hot.
Close it up tight – Once you’re done, screw the cap back on nice and snug.
Pump the brakes – Press the brake pedal a few times to make sure everything is flowing properly.

Understanding DOT 3 Brake Fluid Specifications

What about DOT 3? It’s contributing to preventing brake fade due to its high boiling point and it is also glycol-based, so it absorbs moisture preventing rust and corrosion.

One key point to keep in mind is that, dampness isn’t eternal so if you haven’t changed it in 2 years, there’s a good chance a full flush is required instead of topping up.

When to Seek a Higher Calling: DOT 4 and Beyond

Thinking About an Upgrade? DOT 4 vs. DOT 3

While Chrysler recommends DOT 3, if you ‘spirit drive’ or tow your car, it may be wise to consider switching to DOT 4. Its higher boiling point means it can take more heat before it goes off the rails.

Just keep in mind, DOT 4 absorbs moisture even faster than DOT 3, so it will need to be replaced more often. And don’t forget that mixing in DOT 5 is a no-no, as it’s silicone-based and incompatible with both DOT 3 and 4.

Final Checks and Testing the Brakes

Alright, now that the fluid’s topped up, let’s make sure everything is working:

Pump the brakes a few times. The pedal should feel firm, not spongy.
Look for leaks under the car, especially around the brake lines.
Take it for a test drive – Find a safe spot and try some gentle braking to make sure everything feels right.

When to Call in the Pros

Topping off brake fluid is an easy DIY job, but if you notice any of the following, it’s best to let a mechanic take a look:

The brake fluid level keeps dropping – You could have a leak.
The brake pedal feels soft or spongy – You might need to bleed the brakes.
You hear squealing or grinding when you brake – Your pads or rotors might need replacing.