How to retro-fit the 312mm front brakes to a Mk7 Golf

[golfdave]

While I haven't looked at the ROW cars, it is important to note that for USA, the master cylinder and reservoir ARE different for the Sportwagen with 288mm brakes vs the Alltrack with 312mm brakes:


AT master cylinder is 8V1611021B
AT reservoir is 5Q1611301 or 5Q1611301C (depending on build date)

GSW master cylinder is 5Q1611021A
GSW reservoir is 5Q1611301B or 5Q1611301D (depending on build date)

I then looked up a 2015 A3 Quattro 2.0T, a car which we know comes with the 312mm brakes and it lists the same exact part numbers as the AT, which makes sense since they share the same 312mm front brakes.

So yes, the hydraulics are different between the two different rotor sizes. If you put 312mm brakes on your GSW or Golf, you are not matching them to the correct hydraulics. What the effects are, if any, I do not know.

Looking at ETKA for Europe market
Master cylinder 8V2-611-021(ATE type) or 021 B (TRW type).... has the following PR codes to cover front discs:-
1ZA & 1ZD = 312mm (GTD & DCC cars)
1ZE & 1ZF & 1ZP = 288mm

Master cylinder 8V2-611-021 A.... has the following PR codes to cover front discs:-
1LJ & 1LM = 340mm (R & PP)
1LV & 1ZB = 312mm GTI with 300mm rear discs

So this how to guide is written correctly & my new 312mm brakes are correctly matched to the master cylinder fitted at the factory for the 288mm originals..

Looking at ETKA for USA market
In USA the Master cylinder 8V1-611-021 or 5Q1-611-021 A.... has the following PR codes to cover front discs:-
1ZA & 1ZD = 312mm (GTD & DCC cars)
1ZE & 1ZF & 1ZP = 288mm

https://nemigaparts.com/cat_spares/etka/volkswagen/go/746u/611000/

So a GSW fitted with 288mm brakes in USA will have a master cylinder which will work with 312mm brakes...you are WRONG!!

& to finally knock this on the head it doesn't matter WTF the master cylinder is ...

IF your caliper has "57" stamped on it that caliper is what is used for both the 288mm & 312mm brake disc set-ups as it has a 57mm dia piston, & therefore the hydraulics are the same!! I just had to get a new caliper CARRIER.

Before trying to correct my "How to guides" please read them thoroughly as there is information covering this at the start of this thread!!

 

[tigeo]

golfdave - is the reason that we can't change the disc size in VCDS/OBDEleven b/c it's related to some other coding setting somewhere in the system (based on those PR codes you were talking about)?

 

[tigeo]

I went back to the drawing board and golfdave, as always, is right. I stand corrected. I think we need to make golfdave a moderator.

Dude...don't f with golfdave...hahahahaha. Solid shizzle in this DIYs.

 

[golfdave]

golfdave - is the reason that we can't change the disc size in VCDS/OBDEleven b/c it's related to some other coding setting somewhere in the system (based on those PR codes you were talking about)?

Shouldn't be elsewhere as its mainly the ABS module (can't see why any other module would need the info as it gets it from the ABS unit)...I need to get out & have another VCDS bash at the car,....It could be a "fixed" parameter which is linked to component protection (totally wild guess)

I went back to the drawing board and golfdave, as always, is right. I stand corrected. I think we need to make golfdave a moderator.

Not always right, I do make mistakes.......

once every blue moon!!

 

[chrislane31]

This thread has been very helpful. I have a North American 2015 Golf TDI with 288mm front brakes. I was lucky enough to find some new Euro GTE blue 312mm calipers and carriers.

The swap went fine with new rotors and Hawk pads. I did not change the splash shields because per VW the 288mm TDI cars have the same splash shields as the 312mm cars. Now when driving in hard rain on the highway for long periods when I hit the brakes and it takes a second to dry/clear the water. Only happened twice on long trips with lots of rain and not touching the brakes for long periods of time.

Just seeing if any other TDI guys went through this. Going to try and get the part numbers of the existing shields.

In the dry or not torrential rain the brakes are great.

 

[golfdave]

I did not change the splash shields because per VW the 288mm TDI cars have the same splash shields as the 312mm cars. Now when driving in hard rain on the highway for long periods when I hit the brakes and it takes a second to dry/clear the water. Only happened twice on long trips with lots of rain and not touching the brakes for long periods of time.

Just seeing if any other TDI guys went through this. Going to try and get the part numbers of the existing shields.

In the dry or not torrential rain the brakes are great.

Confussed......So you removed the splash shields??

 

[chrislane31]

Confussed......So you removed the splash shields??

I did not remove the splash shields. Left the stock ones in place. All of my research showed that the US 288mm cars had the same splash shields as the 312mm cars. Now not really sure. At this point not even sure my car had the 288mm brakes. Need to check the old calipers.

 

[golfdave]

I did not remove the splash shields. Left the stock ones in place. All of my research showed that the US 288mm cars had the same splash shields as the 312mm cars. Now not really sure. At this point not even sure my car had the 288mm brakes. Need to check the old calipers.

er??..you think you swapped from 288 to 312 & don't really know??..

288mm discs usually got fitted with the large splash shields for the 312mm discs......so if you had 288mm as factory & you fitted blue GTE calipers/carries then it will fit all ok, & the splash shield will hardly protrude from the disc..

 

[chrislane31]

Hoping to check it out later today. Had a buddy install the blue GTE brakes while doing a service. Otherwise not sure why I only have this issue while driving in hard rain.

 

[chrislane31]

Didn't get the car on the lift, but the shields look to be the same or a little larger than the rotors. At a loss now what can be causing this.

 

[golfdave]

Didn't get the car on the lift, but the shields look to be the same or a little larger than the rotors. At a loss now what can be causing this.

The problem being that when the brakes are totally soaking for hrs in rain & with little usage, that when you do use them it takes a second or so to get "bite"....totally normal..they are bigger discs, more disc to clear of water.....

 

[Faceman]

Didn't get the car on the lift, but the shields look to be the same or a little larger than the rotors. At a loss now what can be causing this.

I've noticed this with the smaller rotors as well. Nothing new, but just may be slightly worse now.

 

[chrislane31]

I upgraded my previous car from 321mm to 345mm and for 200k miles never felt anything like this. It is a frightening 1-2 seconds before the pads bite. I have to just keep hitting the brakes while on the highway in the rain to burn off the water.

 

[chrislane31]

Went in with VCDS and checked my Disc wipe for the brakes and it was set to weak. When the wipers are on it will barely apply the brakes to get rid of water and apply every few mins. I set it to medium to see if that helps.

 

[golfdave]

I upgraded my previous car from 321mm to 345mm and for 200k miles never felt anything like this. It is a frightening 1-2 seconds before the pads bite. I have to just keep hitting the brakes while on the highway in the rain to burn off the water.

I reckon that your pads are sticking or air in the system, or the sliders are sticking.....I've had my 288-312mm conversion for several years now & run both Brembo & ATE discs & pads..& where I live we get loads of salt/snow/rain...& never had the problems of 1-2 secs before initial bite....

If I stamp on the brake pedal in any condition the bite is instantaneous.....if I feather the brakes in cold, wet conditions with the brakes cold then there is a spit second delay...but any brake set-up will have that...