You can
do some maintenance and minor repairs on your own vehicle.
To check
the brake fluid level, raise the hood.
The
master cylinder (mc) is located on the driver's side near the firewall, just
under the windshield.
brake_fluid |
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 very
careful removing the caps.
It's best
to take 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, lets be
cleaning-freaks 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
hot.
Look at
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.
Now then,
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.
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 concentrate on changing the front lines at this time.
Remove
the lid, or caps, from the master cylinder.
Put 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.
Please
don't use adjustable wrenches or pliers...you will 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.
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.
Now, does
the pedal go down about half-way to the floorboard and have a "solid"
or "hard" feel to it? If it does, you're okay.
You can
replace the wheels and go shopping, for more tools, because we will discuss
radiators, heater cores, and hoses next time.