GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

How to fix/improve low soft Brake pedal with Residual Pressure Valves and seal lube

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Awesome!!

FWIIW- I bought the very same red grease to rebuild my stock PP calipers for sale. After all my research that was what I came up with to be the best. Got mine from Amazon.

Touched base with Todd from TCE Performance and he said that was the right lube to use on calipers.

Appreciate you sharing. This took some time to science out.

For some reason inner pads always get worn faster/more than the outer pads. This may be part of the reason.
 

emichel6888

Go Kart Champion
Location
TX
Awesome!!

FWIIW- I bought the very same red grease to rebuild my stock PP calipers for sale. After all my research that was what I came up with to be the best. Got mine from Amazon.

Touched base with Todd from TCE Performance and he said that was the right lube to use on calipers.

Appreciate you sharing. This took some time to science out.

For some reason inner pads always get worn faster/more than the outer pads. This may be part of the reason.

Yes, it seems to be the caliper grease most use, even on many of the track BBK's so i am thinking it should be fine. I am curious, with your BBK do you know the piston displacement? How is your pedal height and feel? Do you get the soft pedal drop when you start the engine?
 

emichel6888

Go Kart Champion
Location
TX
I updated the what this modification does theory drawing to hopefully give a better understanding how and why this works:

Brake pedal theory.jpg

Not only does reducing the piston retraction raise the brake pedal, but apparently if you reduce it enough the stepped MC remains in stage one which also raises pedal height/travel and firmness. So stage two is essentially what you have, and with these minor changes you get stage one. As with many things in life, a high hard one is a lot more fun than soft and low. 😂
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Yes, it seems to be the caliper grease most use, even on many of the track BBK's so i am thinking it should be fine. I am curious, with your BBK do you know the piston displacement? How is your pedal height and feel? Do you get the soft pedal drop when you start the engine?
Pedal height is better than stock. There is still the softening of the pedal when you start the car. I really noticed that when I did a two man brake bleed. You think you have rock hard pedal. 😃 Go to start and its softens up. Hah! Frustrating it’s better with the BBK but it’s there for sure.

With the PP brakes I alway gave them a quick pump headings into the brakes zones to compensate. I carried that over to The BBK out of habit. You will see a lot of pro driver tap tap the brakes with there left foot heading into the brake zone. I can’t left foot brake for shit. Have no finesse With the left foot. Lol

I will need to check on the piston sizes.
 

emichel6888

Go Kart Champion
Location
TX
Pedal height is better than stock. There is still the softening of the pedal when you start the car. I really noticed that when I did a two man brake bleed. You think you have rock hard pedal. 😃 Go to start and its softens up. Hah! Frustrating it’s better with the BBK but it’s there for sure.

With the PP brakes I alway gave them a quick pump headings into the brakes zones to compensate. I carried that over to The BBK out of habit. You will see a lot of pro driver tap tap the brakes with there left foot heading into the brake zone. I can’t left foot brake for shit. Have no finesse With the left foot. Lol

I will need to check on the piston sizes.

It sounds like these modification's would work well with your caliper's. If the pedal height improved with just the calipers; I would guess they have standard cut seal channels and or possibly less piston displacement. Do you know if the seals are lubricated?
I would try it in stages, either install the RPV's first and see what effect that has, or if not already done just try lubricating the piston seals. The inner seal channel on these Brembo calipers are straight cut, and I was able to lube the seals and use the RBV's without pad drag, so I think you should be able to do both for maximum effect.

Left foot braking is one of those things you just have to get used to doing, if you practice it driving on the street until it feels normal... It is just like learning to write with your none dominant hand, you just need to practice. Having a higher firmer pedal does help.
 

GTIfan99

Autocross Champion
Location
FL
Pedal height is better than stock. There is still the softening of the pedal when you start the car. I really noticed that when I did a two man brake bleed. You think you have rock hard pedal. 😃 Go to start and its softens up. Hah! Frustrating it’s better with the BBK but it’s there for sure.

With the PP brakes I alway gave them a quick pump headings into the brakes zones to compensate. I carried that over to The BBK out of habit. You will see a lot of pro driver tap tap the brakes with there left foot heading into the brake zone. I can’t left foot brake for shit. Have no finesse With the left foot. Lol

I will need to check on the piston sizes.

Did you end up doing Macan or something else?
 

emichel6888

Go Kart Champion
Location
TX
Bill, or anyone else with the Stoptech ST40 kit, do you experience the pedal drop when you start the engine? I am guessing no, am I right?
 

GTIfan99

Autocross Champion
Location
FL
It is in his signature, he has "PowerBrake 330x32 BBK". Not sure what they cost, but looks like a nice setup.

I'm on my phone, sig doesn't show.
 

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Did you end up doing Macan or something else?
I have PowerBrakes 330x32 4-piston BBK. I shaved 2-seconds off my lap time at VIR with these brakes.

With Apex wheels new 17” SM-10’s clearing the 350x34 6-piston, I may go to the larger rotor and pad
 

SouthFL_Mk7.5

Drag Racing Champion
Location
South Florida
Car(s)
2019 GTI S
I’d argue 75% of what was achieved here in terms of modulation/feel could have been done by experimenting with different pad compounds. Interesting process nevertheless. Lots of work put into it!
 
Last edited:

Mini7

Autocross Champion
Location
Charlotte, NC
Car(s)
2017 GTi Sport PP
Modulation is very much down to pad compound/driver preference. I don’t care for super aggressive pads as they tend to be an on/off switch. Making them difficult to modulate and finesse brake. Great for hard straight line braking but tricky for trail braking. plus they tend to be hard on rotors in terms of wear.

This thread is more about the mechanical variables. Having a high firm brake pedal right out the gate. This is about master cylinder size and caliper piston size coupled with the mechanical pedal ratio. Not to mention the electronics behind the scene influencing the feel. I’d argue that this is more about engineering and science.
 

SouthFL_Mk7.5

Drag Racing Champion
Location
South Florida
Car(s)
2019 GTI S
Modulation is very much down to pad compound/driver preference. I don’t care for super aggressive pads as they tend to be an on/off switch. Making them difficult to modulate and finesse brake. Great for hard straight line braking but tricky for trail braking. plus they tend to be hard on rotors in terms of wear.

This thread is more about the mechanical variables. Having a high firm brake pedal right out the gate. This is about master cylinder size and caliper piston size coupled with the mechanical pedal ratio. Not to mention the electronics behind the scene influencing the feel. I’d argue that this is more about engineering and science.

Agreed.
Over the years I’ve come to prefer a pad with good modulation as opposed to a hard initial bite as well.
 

scrapin240

Drag Racing Champion
Location
IzzaGolf
Car(s)
Golf
I’d argue 75% of what was achieved here in terms of modulation/feel could have been done by experimenting with different pad compounds. Interesting process nevertheless. Lots of work put into it!
I thought so too, but I was wrong. There isn't enough pressure/bias to move all the pistons. The bottom 2 pistons in each caliper were not being fully pushed out.

see my findings here: https://golfmk7.com/forums/index.ph...de-thread-read-first-post.371028/post-7519084

bottom line: i'm going back to the stock calipers
 
Top