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Bleeding Jeep Brake System

Author: ThePhantum

***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.
Vacuum pump used to bleed Jeep 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:
Connect the hose to the bleeder screw
Use the pump to draw brake fluid from the system

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.***

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