Brake bleed order ...

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par

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I always thought that starting at the longest brake line and working towards the shortest was the way to bleed brakes. But someone mentioned that it varied from vehicle to vehicle. Is this true?
 
some systems need a computer attachment to properly open up the ABS system valves and drain the ABS computer before/during the fluid replacement procedure.

Unfortunately, only euro cars have threaded master cylinder reservoirs which allow for easy pressurized attachment and quick bleeding.

JMH
 
Some newer vehicles, especially ABS equipped cars like JHZR2 said, have special procedures required.

The general rule is still longest line first.

Most modern car makers say that the system never needs to be flushed, which is of course complete nonsense.

John
 
quote:

Originally posted by mechtech:
Actually, most common cars have a split diagonal braking system [RF + LR, and LF + RR]. You don't bleed longest to shortest, but rather the sequence: RR,LF,LR,RF.
The service manual should be checked, but this is by far the most common brake system of the non specialized ABS type.


Correct me if I'm wrong, but with a "split diagonal braking system" bleeding from the longest to the shortest line would achieve the same thing, since the RR/LF is independent from the LR/RF?
 
Actually, most common cars have a split diagonal braking system [RF + LR, and LF + RR]. You don't bleed longest to shortest, but rather the sequence: RR,LF,LR,RF.
The service manual should be checked, but this is by far the most common brake system of the non specialized ABS type.
 
It depends on the car. For example, rear wheel drive Volvos need to be bled from the longest to the shortest. Front wheel drive Volvos need to be bled from the shortest to the longest.


Ken
 
427 - If you are pressure or vacuum bleeding, it probably doesn't matter which sequence is used.
If you are pumping the pedal the reliable old fashioned way, then you can compromise the fluid with air or debris, becuse you can cause movement of fluid to an area that you just purged, or to the master cyl[while you are modulating the pedal to do the other leg]. You'd might have to do it over and over, to get it really right.
This is a poorly worded, memory reduced, late night version ,of the reasoning given in a Bendix brake class some years ago.
They recommended gravity bleeding as a viable method, BTW.
[insert beer drinking icons here > < ]
 
If the vehicle is ABS equipped and the master cylinder is already primed (mounted and filled) you don't need to do anything special. You only need a scan tool to cycle the ABS valves when you mount a new/ rebuilt master cylinder.
 
quote:

Originally posted by Ken2:
It depends on the car. For example, rear wheel drive Volvos need to be bled from the longest to the shortest. Front wheel drive Volvos need to be bled from the shortest to the longest.

Ken


Really? What's the reasoning behind this requirement?
 
quote:

Originally posted by par:
I always thought that starting at the longest brake line and working towards the shortest was the way to bleed brakes. But someone mentioned that it varied from vehicle to vehicle. Is this true?

To answer the question, its true.

Some vehicles are happy with the longest to short route or the Z-pattern bleed.
Others want to be bled in an X-pattern.
Its up to you to research your vehicle. The factory service manual is the best source for bleeding info.
 
quote:

Originally posted by road_rascal:
If the vehicle is ABS equipped and the master cylinder is already primed (mounted and filled) you don't need to do anything special. You only need a scan tool to cycle the ABS valves when you mount a new/ rebuilt master cylinder.

Good info.

Be sure to check your service manual. My 03 Civic's order is LF, RF, RR, LR. Totally different that anything that anyone's mentioned yet in this thread.

[ March 25, 2005, 03:05 AM: Message edited by: noob ]
 
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