got the ARB0 brake hose recall and WPK0 PSM reprogram done

[hifi239]

Called to schedule, and my Massachusetts dealer said they book a week out to have time for parts to arrive. They got the hoses six days later and did the work. They report doing the ARB0 and WPK0. The hoses are longer and the inboard mount is different. I had no complaints with the brakes before and I didn't feel much difference in braking action for my car. Others have said there is an improvement. Actually, after a couple of days, I do feel that at low speed, the brake pedal is higher and firmer.

LEFT BEFORE

LEFT AFTER

RIGHT BEFORE, sharp bend at the fitting (true for both sides)

RIGHT AFTER - much better (true for both sides)

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[Fonndu]

Great pics. Thanks

 

[lcarron]

Called to schedule, and my Massachusetts dealer said they book a week out to have time for parts to arrive. They got the hoses six days later and did the work. They report doing the ARB0 and WPK0. The hoses are longer and the inboard mount is different. I had no complaints with the brakes before and I didn't feel much difference in braking action for my car. Others have said there is an improvement.

LEFT BEFORE

LEFT AFTER

RIGHT BEFORE, sharp bend at the fitting (true for both sides)

RIGHT AFTER - much better (true for both sides)

I did not feel any pedal difference except a much better linear stopping deceleration between 20 and 0 mph. Less squeak Noise as well on my PSCB rotor. Overall this is a good resolution.


Here is the description of the recall:

DURING ROAD TESTING NO ABNORMAL BRAKING NOTED. BRAKE PEDAL FEEL BE IMPROVED FOLLOWING COMPLETION OF ARBO AND WPKO CAMPAIGNS. ALSO NOTE INFORMATION FROM TECHNICAL BULLETIN, "Brake Symptom ? Brake Pedal Travel Perceived as ?Too Far?: Observe Specified Procedure (SY 90/21)" REGARDING BRAKE PEDAL FEEL, "?Stiff Learning Routine? function During regenerative braking (recuperation) , the electric braking torque of the electric machine has to be replaced with the hydraulic braking torque of the wheel brakes (?blending?) at least once during braking, usually shortly before the vehicle comes to a standstill. In order to eliminate longitudinal deceleration fluctuations and brake pedal irritations during ?blending?, the actual stiffness of the brake system must be known as accurately as possible to the control units involved (Porsche Stability Management (PSM) and Electric Brake Booster (eBKV) ) .
If the stiffness learning routine is activated automatically too rarely, the following causes may have been present: The vehicle has not been charged for a long time.
The temperature of the brake discs was > 100~C (212~F) when the learning process was attempted and that of the brake calipers was > 55~C (131~F) .
The front wheels were regularly turned in too far when leaving the vehicle.
Generally, pedal travel is longer when maneuvering.
In order to improve the metering action of the brakes while parking, a smaller brake master cylinder (HBZ) is installed in the Taycan compared with the PHEV vehicles, which extends the pedal travel in order to ensure better metering when parking and maneuvering. In addition, both brake circuits are opened fully at speeds of < 12 km/h/ 7 mph for noise, vibration and other comfort reasons, which also results in longer pedal travel.
Poor friction coefficient of Porsche Ceramic Composite Brake (PCCB)

 

[M3Taycan]

I felt an improved brake pedal feel. Brake travel was shorter and hard , in comparison to brake pedal feel prior to brake hose replacement.

 

[figure1a]

I suppose it could depend where people are in their brake flush maintenance. If they haven't done the flush for 2 years (or possibly longer), then the recall which includes flushing the brake fluid could make their pedals feel firm again.

 

[hifi239]

I felt an improved brake pedal feel. Brake travel was shorter and hard , in comparison to brake pedal feel prior to brake hose replacement.

After a few days, I agree now. The low speed braking to a stop is as above - higher pedal and not as squishy.

 

[romofan]

Thanks for sharing the info and pics. Really helpful to see the differences.

 

[alex_bell]

anyone knows the part number for new hoses? I want to DIY myself

 

[hifi239]

anyone knows the part number for new hoses? I want to DIY myself

Why? This sounds like a bad idea. The work is free.

 

[alex_bell]

Why? This sounds like a bad idea. The work is free.

The dealership is way too far from me, making it too expensive in time*money to drive there for just brake hose replacement

 

[gtm]

The dealership is way too far from me, making it too expensive in time*money to drive there for just brake hose replacement

Since you can obviously get to the hoses just examine them. Pull back the spiral metal sheathing and check for cracks. No cracks then let it go until you need to go in for other work. And you will. Multiple recalls and workshop campaigns require a visit to the dealership. Save it up for one visit. Chances are your hoses are fine and the replacement isn't urgent.

 

[alex_bell]

Since you can obviously get to the hoses just examine them. Pull back the spiral metal sheathing and check for cracks. No cracks then let it go until you need to go in for other work. And you will. Multiple recalls and workshop campaigns require a visit to the dealership. Save it up for one visit. Chances are your hoses are fine and the replacement isn't urgent.

I just have this issue with stopping near traffic lights and sometimes I need to push it harder. My hoses doesn't have cracks, but its bent almost at like 90 degree which definitely isnt good for braking

 

[hifi239]

I just have this issue with stopping near traffic lights and sometimes I need to push it harder. My hoses doesn't have cracks, but its bent almost at like 90 degree which definitely isnt good for braking

Nope, that itself would not cause this. It’s going to be even worse if you replace these yourself because i believe the factory diagnostic computer is needed to properly bleed the brakes after. What you are experiencing will be improved after the dealer replaces the hoses and bleeds. There might even be a computer update available for your VIN that makes braking even better than just bleeding alone. I’d wait until it’s time to get other work done and make the trip.

 

[gtm]

You need to head to the dealer. There are two issues. The cracking brake hoses are one. Workshop campaign WPK0 - "Brake pedal travel perceived as too far" is the other and separate from the brake hoses. And you need to specifically mention this campaign. The dealer might not automatically do it without you mentioning the pedal travel. WPK0 updates the software for the PSM and calls for a "ventilation" (Porsche's term) of the brake system/fluid. The ventilation procedure is fairly involved and requires the PIWIS. Not all Taycans seem to suffer from the pedal suddenly doing nothing and requiring and extra panic push but it's a known problem and WPK0 will almost certainly fix it for you. Totally transformed my brakes when it was done.

Edit: Replacing the brake hoses gets the front lines bled to remove any air. The entire hydraulic system is not bled/ventilated. It's not necessary when the hoses are changed. WPK0 addresses the software and "proper" ventilation.

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