Dumb Mistake: Air in ABS System

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NC_Taycan

NC_Taycan

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Yes - bleeding brakes or flushing the fluid is totally a DIY-possible process (provided you don't get air in). This adventure did not need to happen.

Porsche does use DOT 4 fluid. One DIY note - if you are hoping to completely flush out old fluid, you will not be able to flush it all. Some will remain in the various ABS pump and valve assemblies. I don't consider this a problem. The reason to flush the fluid is to ensure the older fluid that has absorbed some moisture is removed from the hottest parts of the system (hoses, calipers). Brake fluid does not circulate so even old fluid in the ABS pump and chambers will not boil. If you have some other reason to need to flush all the fluid including what's in the ABS pump/chambers, this is a dealer process as the PIWIS tester is needed to actuate the ABS valves.
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r553

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NC_Taycan,
Do you know if a one liter container of DOT 4 is enough for an uneventful brake fluid change? I can understand the dealer went through a lot of fluid getting all the air out of your brake system.
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bsclywilly

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Updating an old thread… Had an interesting experience last weekend swapping brake pads and doing a brake fluid flush for an HPDE event. If anyone finds themselves needing to activate the abs pumps without a PIWIS or scan tool, putting all wheels in the air and applying the brakes will set off the abs. The reason is that the front and rear motors will pulse to try to allow the car to creep at low speed but the front and rear do it out of sync. If you try to activate the brakes it will think one axle is slipping and engage the abs. The only problem with doing this is that it’ll throw some red transmission failure warnings since the computer can’t make sense of the scenario. These clear as soon as you put the car back on the ground.

I had to do this in order to engage the hydraulic circuit to push the pistons back against the pads after I had retracted them fully to fit my track pads. It’s strange that with the ignition off that the hydraulic circuit doesn’t seem to engage so I couldn’t “pump the pedal.”
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