Flushing Fluid From ABS Circuit
#1
Racer
Thread Starter
Flushing Fluid From ABS Circuit
When I flush the brakes on my motorcycle, I use a computer program that activates the ABS circuit to ensure that the fluid that is trapped there is flushed from the system.
So I was wondering how folks flush the brake system on their 991.2? Is a computer program or other device or method used to ensure all the fluid from the ABS circuit is released and flushed?
Thanks!
Jason
So I was wondering how folks flush the brake system on their 991.2? Is a computer program or other device or method used to ensure all the fluid from the ABS circuit is released and flushed?
Thanks!
Jason
#2
Burning Brakes
When I flush the brakes on my motorcycle, I use a computer program that activates the ABS circuit to ensure that the fluid that is trapped there is flushed from the system.
So I was wondering how folks flush the brake system on their 991.2? Is a computer program or other device or method used to ensure all the fluid from the ABS circuit is released and flushed?
Thanks!
Jason
So I was wondering how folks flush the brake system on their 991.2? Is a computer program or other device or method used to ensure all the fluid from the ABS circuit is released and flushed?
Thanks!
Jason
Cheers!
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raaizin (10-10-2021)
#4
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The 991 workshop manual does not direct use of PIWIS for scheduled brake fluid replacement. According to the WSM, PIWIS is needed only if the ABS pump is replaced.
FWIW.
FWIW.
#5
Racer
Thread Starter
Jason
#6
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The way I look at it, we never get 100% fluid replacement no matter what, short of separating all components and lines, flushing with solvent, and drying. The key question is the volume of fluid isolated in the ABS part of the circuit, and what percent this is of the total system. Same as with oil changes.
#7
Racer
Thread Starter
However, the brake fluid in the ABS circuit will not circulate with the fluid in the remainder of the system unless the ABS valves are activated and the brake pedal is depressed multiple times as the ABS valves are being cycled. This is best achieved with the use of device to activate the ABS valves.
How much fluid is trapped in the ABS circuit is unknown to me. But my concern is that stagnant fluid harboring moisture in a delicate circuit is harmful, hence my query for a program/tool/device to more effectively flush the brake system.
Jason
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#8
Racer
Thread Starter
Deleted duplicate post.
#9
Rennlist Member
I agree with "activating the ABS manually" to flush the fluid. I have done it on several other cars with good results. Fill and bleed the system, then drive and brake hard enough to activate the ABS several times and re-bleed. Most tracked cars never have to worry about this since ABS is activated frequently.
#10
Racer
Thread Starter
I agree with "activating the ABS manually" to flush the fluid. I have done it on several other cars with good results. Fill and bleed the system, then drive and brake hard enough to activate the ABS several times and re-bleed. Most tracked cars never have to worry about this since ABS is activated frequently.
Since I don't track my car, I think I'll continue my search for a tool that will manually activate the ABS system.
Jason
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#13
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Unfortunately, the fluid in the ABS chambers only cycles internally when the ABS is "activated". To actually move fluid through both major chambers, you'll want to have upstream pressure, downstream bleed path open while cycling the ABS unit. So the dirty fluid has a place to go. No good opportunity to do that while driving.
#14
RL Community Team
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Indeed, when changing the oil in a 991.2 there appears to be a considerable quantity of "dirty" oil that remains in the oil cooler and the oil lines that connect it to the engine. But this oil is immediately circulated with the "clean" oil when the engine is started. So dilution is the solution in this case.
However, the brake fluid in the ABS circuit will not circulate with the fluid in the remainder of the system unless the ABS valves are activated and the brake pedal is depressed multiple times as the ABS valves are being cycled. This is best achieved with the use of device to activate the ABS valves.
How much fluid is trapped in the ABS circuit is unknown to me. But my concern is that stagnant fluid harboring moisture in a delicate circuit is harmful, hence my query for a program/tool/device to more effectively flush the brake system.
Jason
However, the brake fluid in the ABS circuit will not circulate with the fluid in the remainder of the system unless the ABS valves are activated and the brake pedal is depressed multiple times as the ABS valves are being cycled. This is best achieved with the use of device to activate the ABS valves.
How much fluid is trapped in the ABS circuit is unknown to me. But my concern is that stagnant fluid harboring moisture in a delicate circuit is harmful, hence my query for a program/tool/device to more effectively flush the brake system.
Jason
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Carlo_Carrera (03-18-2020)
#15
Racer
Thread Starter
Thanks for posting the video!
Jason