Quote:
Originally Posted by DracoFelis
If you don't want to pay a mechanic to change your brake fluid, then get a cheap "turkey baster" in the dollar store, and use that to suck all the brake fluid you can out of the place you add the brake fluid. You can then put in fresh brake fluid, replacing the fluid you sucked out (don't ever use that turkey baster for cooking, keep it for your car). This "turkey baster method" is considerably less effective than a full "brake flush", but it is still much more effective than doing nothing. And (unlike a full brake flush), the "turkey baster method" can be done by virtually anyone (i.e. doesn't require a skilled mechanic)...
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If you do it that way, you'll miss the fluid in the lines and brake slave cylinders at each wheel. I agree, it's better than nothing, as the new fluid will eventually mix in with the old, replacing some of it. Though, doing a brake system flush is within the grasp of the average person - you don't need any preticularly special or expensive tools, just the know-how, a little common sense for basic safety (don't crawl under a car only supported by a jack, ect.) and a desire to try something new.
So, here's the know-how... You'll have to supply the common sense and sense of adventure.
Unless ABS cars are drasticly different, all you need to properly flush a brake system (the same process as bleeding air out of it) is:
- Two people
- Box-end wrenches of the proper size for your car's bleeder screws
- A ~2 ft. length of clear tubing that fits on the bleeder screws' barb
- An empty soda bottle
- A quart or so of brake fluid
- Your car's jack and lug wrench
First, you want to keep the brake fluid level in your master cylinder reservoir between the low and full lines. If it drops too low, you'll pull air into the brake system and have to start the bleeding process over again.
Pour an inch or so of brake fluid in the bottom of the soda bottle. You just need enough to keep the end of the clear tubing covered. Slip your box-end wrench onto the first bleeder screw, attach one end of the clear tubing to the screw's barb and put the other end in the brake fluid in the soda bottle.
You'll probably have to remove the wheel to reach the bleeder screw - check your owner's manual for instructions on proper jacking and removing the wheel. Which bleeder screw you start with probably depends on the vehicle, but in the case of CRXs, you start with the wheel furthest from the master cylinder (the passenger rear wheel). From there, you go to the diagonally opposite wheel (driver's front wheel), the remaining rear wheel (driver's rear) and the remaining front wheel (passenger's front).
It's done this way because CRXs (and Civics I imagine) use a dual diagonal brake system - two separate brake circuits powering diagonally opposite wheels. If one circuit fails, you still have a front and rear brake to stop you (in theory anyway). If both braking wheels were on one side, the car would swerve in that direction when you apply the brakes, so they're on opposite corners instead. Anyway, this isn't a strictly Honda site, so I'll stop there.
Back to the bleeding/flushing. You have your tube attached to a bleeder screw, and stuck in the soda bottle with a little brake fluid in the bottom. Have your assistant apply constant pressure to the brake pedal. Use your wrench to loosen the screw a little.
The screw may be stubborn if it's been a while since anyone's done brake work... Make sure you use the loop "box" end of the wrench, and that it's all the way on the hexagon portion of the screw. The crescent end can actually bend out slightly under alot of force, applying alot of stress to just the points of the hexagon, rounding them off. Removing a rounded-off fastener can be a major pain. If you're buying wrenches to do this job, get 6-point box end wrenches, rather than 12-point, if you can. The more wrench in contact with the fastener, the less likely it is to round-off.
Anyway... pressure on the pedal, loosen the bleeder screw. Brake fluid should come out of the screw and flow down the tube into the bottle. Have your assitant call out when the brake pedal reaches the floor. Close the bleeder screw (tighten it), and tell your assitant to release the pedal. Make sure they know not to release the pedal before you say so, or you will pull air back into the system (a not-good thing).
Keeping the end of the tubing submersed in fluid minimizes the amount of air that gets pulled back in if you mess up, but a little bit still gets pulled in through the bleeder screw threads unless the screw is closed. It's not a big deal if you miss closing the screw once in a while - the air should get expelled on the next cycle, but it's counter-productive, so try to keep it to a minimum.
Once the pedal is released, have your assitant apply pressure again and repeat as above.
It's not as tedious as the description makes it sound - you just need to pick short commands to call back and forth and get a rhythm going. Assitant: "Up." (applying pressure, open the screw), You: "Open." (opened the screw), Assitant: "Down." (pedal is at the floor), You: "Closed." (closed the screw, release the pedal), repeat. Remember to keep an eye on the fluid level in the master cylinder reservoir, and top it up as necessary.
Watch the fluid going down the clear tube. If you were bleeding the brakes, you would be watching for air bubbles - once the bubbles stop and you get just fluid, you would move on to the next wheel. Since were flushing the system, you're watching for clean brake fluid. Once you get clean fluid, close the bleeder screw and move on.
Each time you finish a wheel, or any time all the bleeder screws are closed, the brake pedal should feel solid. If the pedal sinks, you've got a leak some place... One of the bleeders may not be closed all the way. If it feels spongy, you've got air in the system. A little bit of give is normal due to the rubber brake lines at each wheel, preticularly once the engine is on and the brake booster is working, but if you bleed all four wheels and have more give than you're used to, you need to go back and bleed the system again.