Here are a few important mechanics tips on how to check your car brake fluid level.
First, raise the hood. The master cylinder (mc) is located on the driver's side near the firewall, just under the windshield. Most master cylinders have two small round caps that you can twist off. Some have one rectangular cap that either snaps on or has a metal bar that clips over the cap.
You can remove the metal clip by inserting a screwdriver under the clip and lifting up on the handle. The plastic rectangular cap can be removed by popping it off with your thumbs.
Be extra careful removing the caps.
It's probably best to use a paper towel and clean around the filler caps before removing. Trash, dirt, or water can cause a lot of problems with your brake system. so, take extra time and effort in cleaning when we work on the brake system, especially the master cylinder. If the brake fluid in the master cylinder with the small round caps is up to the ring at the base of the filler neck it is okay.
In the master cylinder with the one cap the level should be at least one-quarter inch from the top. You don't want to fill the master cylinder too full, it needs room to expand when it gets very hot.
Inspect the fluid. What color is it?
Clean fluid will be clear with a slight shade of yellowish. If the fluid is dark, or blackish, you may have rubber hoses deteriorating inside. The front brakes have a rubber-like hose from the caliper to the metal line coming from the master cylinder...if you have rear disc, they have a rubber line also. Over a period of time, and heat, these lines will deteriorate inside. Disc brakes generate an excessive amount of heat. If it's where you can, poke your finger into the master cylinder and rub the bottom.
Okay, now take a look at the end of your finger. What is that?
If you have black deposits on your finger you need to clean the master cylinder. A note about anti-lock brakes (ABS), just clean the master cylinder with paper towels the best you can. Be sure not to leave any paper particles inside, they could stop-up a line. It is recommended that you change these two rubber lines, because they will only contaminate the master cylinder again.
CLEANING THE MASTER CYLINDER
When you remove the lines you will loose the fluid in the master cylinder: this would be the time to clean the master cylinder and flush the entire brake system. Some master cylinders have two compartments: one for the front brakes (the largest) and one for the rear brakes (the smallest). We will only consentrate on changing the front lines at this time.
First, remove the lid, or caps, from the master cylinder. Place a paper towel over the master cylinder to keep contaminates out. You may want to raise the vehicle and remove the front tires. If you do, be sure to block the rear tires, set the emergency brake, and put stands of some sort under the body of the vehicle just behind the front tires on front wheel drive vehicles. On rear wheel drives you can put your stand under the lower control arm (where the shock is bolted). You will need the proper tools to break the lines loose.
Side point: Don't use adjustable wrenches or pliers ot you could ruin the shoulders on the nuts.
It's best to use a "line" wrench to break the nuts loose and then use the open-end wrench. Don't get any brake fluid on the car body paint...it will peel the paint. Once you have the old lines off and the new lines on, open the bleeder valves on the calipers and fill the master cylinder with the proper brake fluid, most use Dot3.
You may have to wait several minutes for the fluid to come through the lines and out the bleeders. Once the fluid has started running through the bleeders you can close the one on the driver's side and then the one on the passenger side. Check the fluid and add some if it is quite low--never let the master cylinder run out!
You will have air in the line and sometimes it's a bugger to get it all out. After you check the level of the fluid, replace the covers, or caps. Crank the engine and apply pressure on the brake pedal.
Side point: If the pedal feels spongy , you need to open the bleeder on the passenger side.
If you have help, let them press the brake pedal down slowly. As they press the pedal, fluid will rush from the bleeder... tighten it.
Did you see any air bubbles coming out?
Try this two or three times, then go to the driver's side and bleed it in the same manner. Be sure to inform your helper not to let the pedal up until you have the bleeder closed, otherwise, you will get more air in it. Watch the fluid as it comes out, by standing away from it... it smarts the eyes when it gets into them, but fresh water will do the trick to get it out. In face, water is all you need to get it off your hands.
Okay, does the pedal go down about half-way to the floorboard and have a "solid" or "hard" feel to it?
Disclaimer: All information on this site is provided for informational purposes only! By no means is any
information presented herein intended to substitute for the advice provided to you by any health care or other professional
or organization.
