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Wilwood BBK Spongy Pedal Help

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
I had the Wilwood 6 piston bbk installed on my 2017 GTI SE. The kit is technically for a mk6 but a very reputable shop around LA said it is compatible and they have installed many before. After I picked up my car, the brake pedal is spongy and soft the first time I press the brakes, and if I depress and re-engage in quick succession the pedal feels stiff and very solid (how I expected it.) I called the owner and he said it probably needs to break in over the next 100-200 miles but if it doesn't go away then I could return to get the system re-bled. Any advice if this is normal or if there is a problem? The brakes stop well even with the spongy pedal but I do not have much confidence in them.
 

burgerkong

Go Kart Champion
Location
Ontario, Canadeh
Bleed it again, also M/C may be too small, and then there are some that recommend adding check valves. But bleed it first as per manual, with 30 psi, and also tapping the calipers.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
Thank you for the advice, I'm going back to the shop hopefully Monday to bleed the system again, I read on some Audi forums it could be the ABS pump that also needs to be bled. My thought with the M/C is since it's compatible with the MK6 which has a smaller M/C, there should be no problem with the bigger MK7 one.
 

burgerkong

Go Kart Champion
Location
Ontario, Canadeh
Thank you for the advice, I'm going back to the shop hopefully Monday to bleed the system again, I read on some Audi forums it could be the ABS pump that also needs to be bled. My thought with the M/C is since it's compatible with the MK6 which has a smaller M/C, there should be no problem with the bigger MK7 one.

Welllllllll, about that. Turns out there maybe two DIFFERENT MK7 M/C's lol. One has a 23.81mm diameter piston, the other is 25.4mm. But that requires a little more research/validation.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
Welllllllll, about that. Turns out there maybe two DIFFERENT MK7 M/C's lol. One has a 23.81mm diameter piston, the other is 25.4mm. But that requires a little more research/validation.
Oh... Then I have no idea, isn't 23.81mm the same or slightly bigger than the MK6 GTI?
 

jmason

Go Kart Newbie
Location
Frederick, MD
Bleed it again, also M/C may be too small, and then there are some that recommend adding check valves. But bleed it first as per manual, with 30 psi, and also tapping the calipers.
Manual also specifies engaging the ABS after bleeding. Be ready to go through the process multiple times!
 

ketoi12345678

Ready to race!
Location
FL
I have Wilwood BBK on my Alltrack. In my opinion, you definitely need to re-bleed the brake system again, then do the VCDS brake mods (google for this). If this still happens, you may need to bleed the ABS pump. Normally you don't have to bleed the ABS, but if someone works on the brake and leave the brake lines open to the air for too long, this could happen. I left the driver's side brake line open to the air overnight and still be fine. I didn't bleed the ABS pump.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
Manual also specifies engaging the ABS after bleeding. Be ready to go through the process multiple times!
I have no idea if the shop bled the ABS pump or not, but when I go back I'll make sure that's done.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
I have Wilwood BBK on my Alltrack. In my opinion, you definitely need to re-bleed the brake system again, then do the VCDS brake mods (google for this). If this still happens, you may need to bleed the ABS pump. Normally you don't have to bleed the ABS, but if someone works on the brake and leave the brake lines open to the air for too long, this could happen. I left the driver's side brake line open to the air overnight and still be fine. I didn't bleed the ABS pump.
They did half install the brakes and then leave for an hour to find a longer bolt, so I fear some air would've gotten trapped during that. I'll have them re-bleed to start and then road-test the vehicle and see if the ABS pump needs to be bled or not. Which VCDS mods are they? I see from the Macan thread the straight ahead brake stabilization one.

Also can I ask in which order you bled the brakes, especially inboard-outboard on the fronts with the top and bottom bleeders?
 

jmason

Go Kart Newbie
Location
Frederick, MD
LF, RF, LR, RR, outside caliper then inside.

There are two bleed techniques. One is using a power bleeder set to 30 psi. The other is to have an assistant press and hold the pedal forcefully as you open and close the bleeder. This should be done at least 5 times per caliper.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
LF, RF, LR, RR, outside caliper then inside.

There are two bleed techniques. One is using a power bleeder set to 30 psi. The other is to have an assistant press and hold the pedal forcefully as you open and close the bleeder. This should be done at least 5 times per caliper.
So closest to MC to furthest? Ok I'll ask them if they can do it this way, I'm not sure if they use a pressurized bleeder or not but I'll ask, this time I'll watch more closely.
 

ketoi12345678

Ready to race!
Location
FL
They did half install the brakes and then leave for an hour to find a longer bolt, so I fear some air would've gotten trapped during that. I'll have them re-bleed to start and then road-test the vehicle and see if the ABS pump needs to be bled or not. Which VCDS mods are they? I see from the Macan thread the straight ahead brake stabilization one.

Also can I ask in which order you bled the brakes, especially inboard-outboard on the fronts with the top and bottom bleeders?
I bled Rear Passenger, Rear driver, Front passenger outside then inside, Front driver outside then inside. For VCDS brake mods:
Hydraulic Brake Assistant
Hydraulic Brake Booster
Brake Booster

The old way to bleed ABS pump is: you go to dirt road or while in rain, you try to brake hard which made ABS pumps active, repeat few times, then go home and bleed just like normal.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
I bled Rear Passenger, Rear driver, Front passenger outside then inside, Front driver outside then inside. For VCDS brake mods:
Hydraulic Brake Assistant
Hydraulic Brake Booster
Brake Booster

The old way to bleed ABS pump is: you go to dirt road or while in rain, you try to brake hard which made ABS pumps active, repeat few times, then go home and bleed just like normal.
Thank you I'll check out the VCDS mods, I heard that for ABS you can also do it through VCDS, but I am going to try to engage ABS today on a quick road-test but I'm on 240 treadwear tires and I haven't engaged it on this car before.
 

Rafiki76

Ready to race!
Location
Los Angeles
Car(s)
MKVII GTI
Thank you for all the advice, I went back today and they bled the system again including the ABS pump and they found and removed some air bubbles, the brakes now feel incredible.
 
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