Brake Bleeding Sequence-sense

[mechtech2]

The Gospel , mantra, and general rule for years is to always bleed the farthest wheel cyl first, then work your way back to the nearest to the master cyl.
But I can't see why, after much thought.
It doesn't make hydraulic sense.

OK. Let's say you bled your brakes farthest to nearest.
That means the next time you do it, your nearest was first bled! Or somewhere in the middle, depending.

If you have ABS, follow whatever the manual says - they can be fussy.

 

[cchase]

I believe the reason they specify to do the furthest from the master cylinder first is because....

Imagine bleeding the closest brake first. You could conceivably get this line running clear. However, the furthest line may now have dirty fluid near the caliper and clean fluid in the line. If you then move on to another caliper, you may end up with dirty fluid entering the furthest line again.

Thus, when you go to bleed the furthest caliper, you may see clean fluid coming out, but in actuality have dirty fluid upstream and not a fully flushed system.

By working from most distance to least, you insure that when you hit clean fluid, it's fresh the whole way back to the master cylinder.

 

[Audi Junkie]

Just drain the whole thing and start over. The sequence thing is bunk.

 

[bdcardinal]

Originally Posted By: Audi Junkie
Just drain the whole thing and start over. The sequence thing is bunk.


makes it incredibly complicated on ABS systems where you need a scan tool to override, especially on hybrids. the sequence on my car is lf, rf, lr, rr. made even more complicated by the clutch sharing the reservoir and each caliper having dual bleeders (factory Brembo 4 piston on all 4 corners).

 

[bepperb]

I doubt it matters much.

For what it's worth, on both my cars the ABS actuator is above the passenger front wheel. This means the brake line to the FR is shorter than the FL, the opposite of tradition, but it doesn't stop Toyota from recommending rr, lr, rf, lf and Honda lf, rf, lr, rr.

Drain an ABS system? Enjoy your trip to the dealer. Or maybe you have a better scan tool than I.

 

[bigmike]

I just bleed them twice, going from farthest to closest. I bleed them, go for a drive, activate the ABS on a back road, bleed them again. Works great. I'm sure having a scan tool would be easier, but then again it removes some of the fun.

 

[brianl703]

Originally Posted By: bepperb

Drain an ABS system? Enjoy your trip to the dealer. Or maybe you have a better scan tool than I.


The Snap-On Verus scantool can perform an ABS bleed on a '97 Crown Vic. That's only necessary if the ABS hydraulic module has been replaced.

 

[J. A. Rizzo]

I have seen a few manuals that do not recommend the "furthest wheel first" pattern. I think the 07 Subaru Forester says to start with the driver's front, go to passenger, then the furthest, then the driver's rear. I don't get that logic at all. But I did it like the conscientious brake fluid changer I am and everything is working great. Just not sure why it would be that way.

I have also done cars using the "furthest wheel first" mentality, passenger rear, driver's rear, passenger front, driver front, on a car that recommended a different pattern and everything also turned out fine. I dunno.

 

[1 FMF]

Originally Posted By: bigmike
I bleed them, go for a drive, activate the ABS on a back road, bleed them again. Works great.

that won't purge air out of the system,
the bleeders are closed at the calipers and brake fluid is not moving through the lines.

it does not matter on 4 wheel abs where individual brake lines are leaving the ABS modulator then going to each wheel.