BVCRD wrote:
Daksport wrote:
I disagree. If I had just bled my brakes a year ago with a complete flush, there is NO need to do it again if I were putting on new pads
. Fluid lasts from 2-3 years depending on the amount of humidity in the air where it is driven. To safely bleed these brakes, just crack open the bleeder nipple, put a drain hose on it and catch it in a container. No pumping or that nonsense. Gravity bleed. Do rears first. Make sure the fluid doesn't get low in the master cylinder. Takes 1-1/2 hours to do it all.
Brake fluid should be tested at least once a year,water in the fluid is not the big issue as is corrosion is.Most shops have the test strips,they test for copper content which is a result of corrosion.Some auto makers have a service interval for brake fluid flushes,most are 2 years,but regardless you should have the fluid flushed at least every 3-4 years(and that is pushing it).
No need to flush/bleed the system unless you fluid is bad(test strips) or you break open the system(put on new caliper or master).There are many ways to flush/bleed the system and gravity bleeding is the worst,just a step worse then the old pumping method.There are other considerations depending on what type of master you have and how it is mounted in the vehicle.You want the end of the master(the end farthest from the brake booster) to be lower then the booster side,very important if you replaced any component.You also want to depress the brake pedal about 1"-2"(held with brake depressor) when flushing/bleeding as this will allow all the brake fluid to be flushed out of the master.
Compressing the caliper pistons without opening the bleeder can be bad,the reverse pressure can reach well over 100psi which can push the corrosion and sludge back into the proportional valve(and ABS pump is you have ABS) and master which can cause function issues.You would be amazed on all the crap behind the caliper pistons.
Reverse flushing/bleeding is the best as it pushes the air up and out the master,they way air wants to go and the easiest path for air.This is done by injecting fluid through the bleeder and filling the master(after removing most of the fluid from the master 1st).I use the Phoenix System and it works and works very well.
http://www.brakebleeder.com/