Bleeding
Jeep Brake System
***DISCLAIMER - Please note that this
writeup reflects my experiences only and anyone using it for reference
or as a guide, etc. does so at their own risk. You may link to this
writeup, but you must obtain my permission to re-post it elsewhere.***
While overhauling my
Jeep
Cherokee's front brake system, it was
necessary to bleed the brakes. So if you didn't replace your
calipers
(or otherwise open up the system to the air), you're probably asking
why you should bleed your brakes. Just like any other fluid in your
Jeep, brake fluid should be changed periodically. One quality about
brake fluid is that it absorbs moisture, which not only makes the fluid
less effective...it lowers the boiling point. If the fluid boils, gas
is released and suddenly there's air in the line. Bleeding every so
often (1-2 year intervals) helps prevent this.
There are tons
of writeups and methods for bleeding brakes (just do a
google search). I prefer to use a vacuum pump. It allows one person to
do the job and there is no necessity to touch the brake pedal, allowing
me to watch the master cylinder (it should NEVER be run dry) as well as
what is coming out of the system. Also, like the c-clamp it serves
other purposes besides just bleeding brakes...it works anywhere you
need to create a vacuum. You can pick them up at most auto parts stores
for around $50...I think Wal-Mart even sells them.
Some people are
going to chime in about speed bleeders which are very
sweet and make quick work of bleeding brakes...but if you're like me
and have 4 vehicles to maintain, consider buying a set of speedbleeders
for each one at around $50 per vehicle. Then compare that to a $50
vacuum pump that has other uses as well.
Anyway, back on
point...this is the vacuum pump in the configuration
used for bleeding brakes.
A few general
rules first, always start at the wheel with the longest
hydraulic line to the master cylinder and work around the vehicle to
the shortest. For us here in the States it would be right rear, left
rear, right front, left front. Never let the master cylinder run out of
fluid, so make sure to have plenty on hand. Also, don't re-use the
fluid...would you drain the oil out of your engine and then turn around
and pour it back in?
The process
itself is simple but time consuming, connect the end of the
hose to the bleeder screw, use the pump to create a vacuum and then
slowly and slightly open the bleeder screw:
Check the master
cylinder often and add fresh fluid as necessary. When
the fluid runs clear and you see no air coming out of the line, close
the bleeder screw and move on the the next wheel in sequence.
After all four
corners have been bled, start the vehicle and step on
the brake (you might have to pump them to compress the new pads onto
the rotors and bring the pedal up), then turn off the engine and hold
the pedal down. If the pedal does not sink after 15-20 seconds, you're
set. If the pedal does sink, the system should be bled again.
Once that's
done, install your wheels and take the vehicle for a test
drive, but go easy at first. If something is going to fail, it will
most likely be right away. Besides, you don't want to glaze over your
brandie new pads.
Stoppin' on a
dime,
Steve
***DISCLAIMER - Please note that this
writeup reflects my experiences only and anyone using it for reference
or as a guide, etc. does so at their own risk. You may link to this
writeup, but you must obtain my permission to re-post it elsewhere.***
