Quote:
Originally Posted by Kenth
Not if you bleed by gravity only.
I have found the fluid inlet often sits lower, close to the bottom of the "well", than the bleeder screw.
Change the fluid is best done by the "two person" method or pressurize the master cylinder or using the vacuum method at the bleeder valve.
The bad fluid needs to be pushed or sucked out of the system.
FWIW
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I've rebuilt plenty of calipers/wheel cylinders that were flushed by the 2 person method that were loaded with sediment. I always rebuild any brake components myself if the core is salvageable, so I've been inside of many hydraulic brake systems. If I can buy a kit for the vehicle I rebuild the part myself, simply because I don't trust the rebuilders. Unless the vehicle is low mileage, they all have sediment in them
Sorry, not buying that your going to remove all the crap in a caliper just by bleeding them with 2 people, I've seen the results myself.
Here in Ohio we have high humidity, and road salt 3-4 months of the year, flushing the hydraulic portion of the system could get you a tiny bit more life from the system, too many negative things in the environment here that just replacing fluid won't help.
One more thing, due to the road salt (recently we started getting liquid calcium, which is even more corrosive than just road salt) we live with year after year, the bleed screws are usually frozen, trying to bleed them may end up, either a very expensive proposition (parts replacement), or labor intensive drilling the bleed screws out and trying to save the core) when the bleed screw shears off.
Try explaining to your customer that you were going to flush the brake fluid for them, and now the bill is $500 because of the damage you did trying to save them money by flushing the brake fluid.
Did you save them any money overall? Did you make any money, or did you donate a lot of time, and not get paid for it?
That goes over like a lead balloon, who pays the bill? Do you eat the parts, and labor to keep the customer? Or do you charge them for parts, and labor, and piss them off so they never come back?
Explain to them up front that the flush could be between $50 to $500?
If it makes you feel better to flush systems, then have at it, the parts wear no matter how much you flush the system. I don't recall seeing any vehicle go 200,000 miles with out rebuilding/replacing something in the hydraulic portion of the brake system.