Quote:
Originally Posted by Sirrotica
You're forgetting that the main reason people post about bleeding brakes is that they can't seem to get the air out of the system. Gravity bleeding does it more efficiently than other forms of bleeding, most times once is all that is required.
The vacuum method, and pressure bleeding, either with pedal movement, or with an air pushing fluid through the system many times don't work the first time, and are repeated over and over to purge the air. Gravity will purge air at the master cylinder as well as the bleeder because without pressure against the fluid column the air will travel upwards to the master cylinder, and you effect air letting at both ends of the fluid column instead of forcing all the air downward through the bleeder multiple times.
Pressure bleeding still ends up on the floor if you're not abundantly careful, and has the potential to squirt fluid all over the undercarriage, so the argument that gravity bleeding is going to remove paint, and is messy is a weak point.
Efficiency is why I prefer to use gravity bleeding, it works quickly and most time once is all that is required to completely purge the system. Even if someone isn't in a production setting, it's still the best choice of, one and done, and that is the main point, to get it done the first time correctly, and move on.
BTW, pumping the pedal to remove air is a great method to remove paint on a fender, inner fender, and firewall. I've seen more paint on left fenders ruined by using this method than I can count by trapped air forcing the fluid back through the system when the pedal is released during the bleeding process. It's much easier to touch up undercarriage paint than it is the paint on the top of the fender. All it takes is leaving the cover off the reservoir one time while bleeding to cause a ruined exterior paint job.........  |
i've never had a problem getting air out of the system doing it manually, either adding a new caliper, new lines or a whole new system with a new master & prop valve, manual works perfect & is clean as can be with a hose & jar with some fluid in it.
never had fluid on the floor or "squirt all over the undercarriage" with just a basic set up of a hose fit tightly on the bleeder & a box wrench to open & close it, worst case you put a piece of cardboard down in case you knock over the jar or the hose pops out but thats very rare if ever in my experience.
however i have watched friends do gravity bleeding & watched the fluid drain all over the caliper, spindle & lower control arm or the backing plates & axle tubes then drip onto the ground. worked great but i chuckled at how messy it was & realized i would never do that on a clean or restored car. that isnt an "argument" just stating why i prefer to do it manually & pointing out that unless you are "abundantly careful" gravity bleeding is messy & fluid can/will eat paint if/when it touches it.
BTW, the whole trapped air pushing fluid & eating paint on a fender & firewall thing makes no sense, who leaves the cap off the master when bleeding??? never heard of that one but i suppose it can happen... so the argument of trapped air eating paint on a fender/firewall is definitely a weak point.
bleeding brakes isnt rocket science, you can do this how you want & others can do it how they want, both ways work fine & doing it manually is also one & done & is usually much cleaner when its done right.