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

[golfdave]

Disclaimer:- This info is for community usage. I am NOT affiliated to, or sponsored by, any company/individual to promote them or their products. Companies/individuals may NOT use my name, photos, or threads/technical guides, for financial or personal gain (fraudulent misrepresentation).

WARNING:-
If you have a very basic spec Mk7 Golf a with low powered engine your car many be fitted with the brake caliper parts code 5QM 615 123 or 124 & therefore have the 276mm x 24mm front brake discs (PR code = 1ZF). This set up uses older style calipers & completely different hub carriers. The 288mm, 312mm, & 340mm front brake disc conversions will NOT work, unless you get the hub carriers for the 288mm, 312mm, 340mm brakes as well!

Vehicle used in this guide
UK spec, 2014yr model, Mk7 Golf Estate (GSW), GT (Highline) trim, 1.4lt TSI (140PS) CHPA petrol engine, MQ250 6speed manual gearbox, multi-link rear suspension.

Vehicles that this guide is applicable to
Any MQB platform VAG (Audi/Seat/Skoda/VW) cars.

Introduction
I have never been 100% happy with the 288mm front brakes on my Mk7 Golf. I think VW designed the 57mm piston braking system for the 312mm discs & just downsized the disc to 288mm as another option. The GTI-PP/R/CCS all have a 340mm disc with a 60mm piston, so an increase of 28mm diameter for disc & 3mm diameter for piston. The 288mm disc is 24mm smaller than the 312mm yet still has the same piston. This makes the piston really grab the disc by placing loads of pressure on it & because the pads have a smaller disc to get rid of the heat, pad fade is inevitable! In reality the 288mm discs should have a smaller piston, say 55mm, this size combination is what VW use on some low spec models of Mk7 Golf in NAR.

So what can be done? If you are about the order a car, double check with the dealer that the DCC (Dynamic Chassis Control) comes with the GTD 312mm front brakes & aluminium front knuckle/wheel bearing carrier. & order that option. Otherwise continue reading!

Research
Upgrading the brakes on VAG cars using parts from other higher performance VAG cars has been common for years. This 312mm brake set up is used on various other MQB platform VAG cars. On all basic Golf’s (Not GTD/GTI/R, etc) the standard & factory option “sports” dampers are 50mm diameter & fit into a cast iron hub carrier which is machined for the 80mm diameter wheel bearing.
The optional Dynamic Chassis Control (DCC) dampers are thicker at 55mm diameter. So to fit DCC to a “basic” Golf, VAG decided against making a 55mm cast iron hub carrier as they assumed more of the “sporty” cars would be ordered with DCC. So they use the existing aluminium/alloy hub carrier which is standard on the GTD/GTI/R/ & Audi MQB cars. This is made for all 55mm dampers (DCC & non-DCC) & is machined for a 85mm diameter wheel bearing to cope with more torque etc..

However the spacing’s for the brake caliper carriers are exactly the same on both types of hub carriers! So you could fit the big 340mm Golf “R” brakes to a Golf with 288mm brakes & a cast iron hub!! But for some strange reason VAG insist that the alloy hub is fitted with the 312mm brakes even when fitting DCC to a car with 288mm brakes! This must be costing them money as a bigger 312mm disc & bigger carrier bracket cost more than fitting the 288mm set up that the car would otherwise have fitted!!

The 288mm & 312mm discs use the same shape pads, same single 57mm piston callipers, splash shield, ABS sensor wire etc. The only difference being the disc diameter & the calliper carrier (bracket) which holds the calliper further out to fit the bigger diameter disc.

WARNING:- some 288mm front discs have been fitted with 55mm piston calipers which will NOT put the correct pressure on the pads for the 312mm discs. The easiest way to check what you have is NOT using VIN number, or PR codes, as there has been loads of confusion, with contradictory evidence! But to remove a wheel & look at the rear face of the caliper where it will have either "55" or "57" stamped into the caliper body. This is the piston diameter the caliper was drilled to accept, eg 55mm or 57mm!

TRW who make the front brakes for the 288mm & 312mm sizes state different part numbers for the single 57mm piston callipers. The only differences are the side (drivers or passenger) & colours;- Silver (zinc plated) for 288mm, Grey painted for GTD (& DCC), Red painted for GTI, Blue painted for GTE.
They also state different part numbers for the caliper carriers (brackets). The only differences are the spacing for the disc size, the side (drivers or passenger) & colours.

Regarding the “drivers” & “passenger” side specifications for the caliper carriers:- The reason for different part numbers is that the carries are a completed "assembly" made up of several different parts. The cast metal brackets are exactly the same, the only difference is that the sliding pins, which are different, are inserted into different holes. One pin is solid which has more side to side movement in the hole. The other pin has a replaceable plastic sleeve/bush on the lower half which restricts the side to side movement! I have found this to be the case in other VAG calliper carriers. This is to allow room for heat expansion & some caliper movement. On previous calipers both pins were solid & I suspect caused wear & enlarged the holes in the carrier bracket. Now to prevent this you have the replaceable plastic sleeve/bush on one pin. You will find that one pin has to be “uppermost” (one with the black plastic sleeve/bush) & the all metal pin is lower most, which is why they are sold pre-assembled as “left” & “right”. There is nothing to stop you buying two of the same side & swapping the pins around on the “wrong” side to make a “pair”. I wish I had known this for certain 100%, as it would have saved me £76.71.


The VAG factory “P” codes for 288mm & 312mm front brakes:-
1ZE & 1ZP = 288mm disc size, Silver Zinc plated
1ZA & 1ZD = 312mm disc size, Grey painted, GTD & DCC equipped cars which would otherwise have 288mm
1ZB/1LV = 312mm disc size, Red painted, GTI
1ZC/1ZG = 312mm disc size, Blue painted, GTE

 

[golfdave]

Part 2 of 5
Parts required

VAG ETKA illustration for VW Golf MK7/Brakes/No. 615-000, -030, -035, -037

Item No. 6:- 8V0 615 125A (TRW part No. BDA1180), Caliper carrier bracket (Left), complete with items No.7 & No.8, £155.53 (Dealer)
Item No. 6:- 8V0 615 126A (TRW part No. BDA1181), Caliper carrier bracket (Right), complete with items No.7 & No.8, £155.53 (Dealer)
Item No. 10:- Pads, complete with items No.8 & No.11
Item No. 12:- Disc 312mm should come with item No.13


Other items which may be required depending on existing condition:-
Item No. 4:- N91 084 901, Hex head bolt (M14x55mm) for cast alloy hub
Item No. 4:- N90 948 802, Hex head bolt (M14x35mm) for cast iron hub, £4.56 (x4)
Item No. 7:- 7N0 698 647 A, Caliper slide pin covers
Item No. 8:- WHT 003 250, Flange hex head bolt (M8x22mm), £1.32 (x4) (usually come with any pad set inc aftermarket)
Item No. 11:- 8V0 615 437, ABS wear sensor contact wires (usually come with the new pads set)
Item No. 13:- N 106 483 01, Countersink TX bolt (M6x12mm), £0.40 (x2) (usually come with any disc set)
Item No. 14:- 5Q0 615 311 G, Splash shield left
Item No. 14:- 5Q0 615 312 G, Splash shield right
Item 15:- WHT 005 227, Oval flange head TX socket bolt (M6x12mm)



Big bolts 200Nm (148lbft), can be reused just clean thoroughly!
Calliper pin 35Nm (26lbft) (always renew or thoroughly clean & use blue threadloc if ok)
Splash shield 12Nm (9lbft)
ABS sensor & brake disc screw 8Nm (6lbft)

Misc info
Unsprung weights & considerations:-
Caliper carrier brackets:-
288mm size 1.54kg each
312mm size 1.68kg each
Discs:-
TRW plain OEM 288mm = 7.45kg each
TRW plain OEM 312mm = 8.75kg each
ATE power discs 312mm = 8.25kg each
Brembo Max 312mm = 8.6kg each
Discs & pads I used:-
ATE Power discs 312 x25mm:- 24.0325-0158.1
ATE pads :-13.0460-2785.2

I have since removed these as I had problems with the original grease causing the calipers to stick & causing due wear on the pads/discs...so I now run Brembo Max discs & Brembo plain pads.
I prefer a disc with a groove to clean stones & de-glaze the pads, x-drilling I do not like as the discs can crack between the holes. ATE do not recommend their low dust ceramic pads with these “Power” discs as you get “squealing”, as these pads are designed for plain discs. The Power discs are designed for plain pads!

 

[golfdave]

Part 3 of 5

Removal & preparation work
It is best to be able to jack up & have the whole front end of the car in the air & supported by either axle stands, or in my case two 3ton professional trolley jacks! Slacken off the respective wheel bolts whilst the car is on the ground, then jack up & fully remove the wheel bolts & wheel. Using a 17mm spanner on the caliper slider pins hex shoulder (next to gaiters) to stop rotation, undo the caliper bolts using a 13mm socket (some have a T-Star T-45 built into the head). Remove the caliper & the pads stay with the caliper carrier (bracket). Do not let the caliper hang by the brake hose! Support it or hang from the suspension spring using wire/cable ties. You might have to undo the clip holding the brake hose to the retaining bracket to allow more movement of the caliper. To undo the clip use a slot head screwdriver & prise upwards. Note down the correct orientation of the pads & where the ABS sensor wire is located etc. as this is important!! Now remove the pads & undo the ABS sensor wire connector plug. Using a breaker bar fitted with a 21mm socket (preferably a 6 sided socket, not a 12 sided) undo the two big bolts which locate the caliper carrier to the hub carrier. Be careful as these are done up to a high torque setting!!! Remove the carrier then undo the brake disc retaining screw (T-Star T-30 bit/key), & remove the disc.

Now push the piston all the way back into the caliper, using a piston tool, or you could use any spreader clamp etc.. However, you must bleed off the surplus brake fluid from the caliper bleed nipple whilst you push the piston back in. If you do not then you will force the fluid back into the ABS unit & you could flip (invert) the seals on the ABS valves! The bleed nipple must be pointing upwards or higher than the rest of the caliper body to prevent too much air getting back in when you bleed off the surplus. Also you only have to undo it just enough so that the fluid just comes out. You will need a 11mm spanner, a container & hose to undo the bled nipple & drain of the surplus fluid. When you are finished pushing the piston in & bleeding the surplus fluid off, “nip up” the bleed nipple tight.

You might have to wire brush/sand rust etc off the hub face. Using brake cleaning spray I cleaned the splash shield, hub, hub carrier & mounting points for the carrier/bracket. Because of the high torque settings on the main bolts & the fact that small dirt particles can push the disc & callipers fractionally out (causing brake judder etc) items need to be properly cleaned & wiped down with clean cloths or workshop blue paper towel/roll.

 

[golfdave]

Part 4 of 5
Fitting

Once you are sure the mating surfaces between the disc & hub are level & very clean then fit the disc (align the correct holes) & torque the new disc retaining screw up to 8Nm (6lbft). Again making sure that the mounting faces between the hub carrier & caliper carrier are clean & level fit the new bigger carrier/brackets using the correct 35mm long bolts for the cast iron hub carrier (55mm are for the cast alloy version). If you are re-using your original bolts make sure these are thoroughly cleaned/de-greased. Torque up these bolts to 200Nm (148lbft) & take care!!

Now you must very lightly grease the contact areas between the pads spring clips & the caliper carrier bracket. If there is no grease included with the new pads then only use something like VW hot bolt paste (Loctite LB8009 heavy duty) & not Mintex Ceratec or copper grease! Now fit the ABS sensor to the correct inside facing pad. Usually these sensors have a plastic block with a metal spring clip. These clip into the notch on the outer edge of the pad & can only easily fit one way, also remembering the way the originals came off. Using the same grease apply a thin layer to the piston contact edge & the two “prongs” of the caliper which contact the outside facing pad. Now slide the caliper back over the pads & using either new bolts or the old ones (cleaned & with blue (medium strength threadlock)) hand thread them through the caliper holes & into the slider pins. Now torque then up using the “opposing hold” (17mm spanner to stop rotation on the caliper slider pins hex shoulder (next to gaiters)) torque up the caliper bolts using a 13mm socket to 35Nm (26lbft).

Now connect up the ABS sensor & double check everything is it’s correct place, e.g. the brake hose is secure, retaining clips are ok, ABS sensor wires are not caught on anything, all bolts done up correctly etc., etc. Now refit the wheel & hand tighten (socket & small ratchet) the bolts in a start pattern (diagonals as if drawing a 5 point star without lifting pen of paper), then lower the car back down to the ground & full tighten the wheel bolts up to 120Nm (89lbft).

Now take it easy on the brakes as per the pad & disc manufactures instructions/recommendations until they bed in!

I notified my insurance company of this modification & stated to them that the car would have come with them from the factory if I had ordered the optional DCC dampers. They could not understand that for the same engine output that the brakes would increase in size just for adjustable dampers! The only additional questions they asked was who fitted them & where the parts were from (they were happy with my answers & qualifications!) Anyway no extra increase for me as they stated that I have made the car safer by fitting better brakes using factory fit/OEM parts made for the car.

So enjoy much better braking & less over heating!

 

[golfdave]

Part 5 of 5

Bonus modifications & review of the brakes after bedding in :-

I also decided to fit the Audi RS3 brake cooling air directing flaps to the front lower wishbones.

See my how to guide here:-
How to retro-fit the front brake air guides from the Audi RS3 (2017->) | GOLFMK7 - VW GTI MKVII Forum / VW Golf R Forum / VW Golf MKVII Forum

Results
I have recently done a 194mile round trip over what are widely acknowledged as some of the best driver’s roads in the UK, the A939, A97 & A93. These are very twisty & have several very steep descents & climbs! The way I drive the route there is a steep decent after 1.5hrs solid driving & last time the brakes were rumbling & had totally faded on the last bend of this particular descent! This time with the bigger brakes & the cooling there was NO FADE, NO RUMBLING, & I didn’t have to use more than 1/2 the brake pedal the whole trip!! Nice, progressive, not grabby, WOW! Basically how it should be from the factory!!

Conclusions
Basically how my car (estate) should been from the factory!!

 

[Bäsemödel]

Great write up! Have you tried/investigated any other pad options? Low noise/dust while still having above OE performance?

 

[golfdave]

Great write up! Have you tried/investigated any other pad options? Low noise/dust while still having above OE performance?

This is not the thread for that!...

There are plenty of existing threads on that in the wheels/brakes section.....

Personally speaking I hate cross drilled, prefer grooved, & have in the past 22yrs had various makes.

The driving I do (not much now) & where I live eats brake discs & pads with sand/salt etc so no point in getting very fancy racing stuff...been there done that!

 

[25PSi]

8V0 615 125A and 8V0 615 126A

Where exactly did you order yours?

Sorry i am too fast to ask. Found my own answer: https://www.vwpartsoutlet.com has both sides for $127.50 each

 

[o_a_ravi]

Thanks for the detailed DIY instructions GolfDave. I am looking to do this upgrade soon.

Looking to purchase the kit from a US seller - https://shopdap.com/store/make-mode...k7-gti-pp-front-brake-kit-slotted-rotors.html

I think they sell the 340mm Discs, Caliper Bracket and Calipers (GTI kit).

If i do this mod, either using your mod as described by you above or by using the kit from ShopDAP., do you know if there will be enogh clearance between the Caliper and Inner Wheel Spokes ?

Mine is a 2017 Golf TSI Wolfsburg with stock brakes, with 18 Inch Preston Wheels (18 X 7.5 ET51).The stock calipers are few millimeters inside the inner wheel spokes., so any thing little bigger will hit the wheels.

Any idea if there will be clearance issues or do i need some spacers to avoid this issue.

THanks,
Ravi.

 

[golfdave]

- https://shopdap.com/store/make-mode...k7-gti-pp-front-brake-kit-slotted-rotors.html

I think they sell the 340mm Discs, Caliper Bracket and Calipers (GTI kit).

If i do this mod, either using your mod as described by you above or by using the kit from ShopDAP., do you know if there will be enogh clearance between the Caliper and Inner Wheel Spokes ?

Mine is a 2017 Golf TSI Wolfsburg with stock brakes, with 18 Inch Preston Wheels (18 X 7.5 ET51).The stock calipers are few millimeters inside the inner wheel spokes., so any thing little bigger will hit the wheels.

Any idea if there will be clearance issues or do i need some spacers to avoid this issue.

THanks,
Ravi.

Sorry I do not know the inner dimensions of your wheels...diameter should be ok, but as for the back of the spokes hitting the caliper face...I have no idea. Maybe ask on the general section?

Also you will have to push the pedal down more to move the piston the same distance as before as your master cylinder is for the 57mm brake pistons, ...GTI PP & R which use 60mm brake pistons have a different master cylinder.

Also insurance will have to be told & personally I would go for a lighter weight 4 pot NSQBBK for that money..

 

[breaking badly]

Any OE wheel for the Mk.VII Golf will clear R/PP brakes.
Your Preston wheels fit both GTI PP and Golf R nicely.
To be honest though I don't like the idea of red colored
and GTI badged calipers on a non-GTI. Your decision.

 

[golfdave]

A question I have relates to the wheel bearings. You say they are different sizes for the aluminum vs cast knuckle, can you elaborate. I'd like to do a 55mm knuckle swap when I do my brake swap just so I'm only down there once but I'm puzzled to the bearing. The only difference in the bearing was an A at the end of the part number between a US Golf and GTI. I believe the bearing is even listed to work on both the one is just a revision. Nice write up! I might do this while I wait to buy the PP ones too after my clutch job lol

Bearing is specific to the hub carrier, the alloy one has to have the 85mm bearing....

So if you want to fit the alloy hub carrier/knuckle you fit the 85mm bearing.....the 80mm will not will fit...

As for fitting "R" 340mm brakes to a car built for 288mm brakes see my post above....not the best solution I would advise against it & spend the money elsewhere.....the 288 to 312mm swap with good discs & pads is way more than man enough for spirited twisty road driving as I know...

 

[o_a_ravi]

Sorry I do not know the inner dimensions of your wheels...diameter should be ok, but as for the back of the spokes hitting the caliper face...I have no idea. Maybe ask on the general section?

Also you will have to push the pedal down more to move the piston the same distance as before as your master cylinder is for the 57mm brake pistons, ...GTI PP & R which use 60mm brake pistons have a different master cylinder.

Also insurance will have to be told & personally I would go for a lighter weight 4 pot NSQBBK for that money..

Thanks for the advise GolfDave., seems like 288mm to 312mm seems to be the best value for the money.

Since you have already done this mod, do you see a good difference in terms of braking ?

Somehow I feel the stock brakes are not very sufficient even for daily driving, it dont do track or any spirited driving though...

 

[golfdave]

Will the bearings interchange with the different axles? Sorry this is new territory to me lol.

Yes they will fit with your old axles from what I understand.

Thanks for the advise GolfDave., seems like 288mm to 312mm seems to be the best value for the money.

Since you have already done this mod, do you see a good difference in terms of braking ?

Somehow I feel the stock brakes are not very sufficient even for daily driving, it dont do track or any spirited driving though...

I did mention in my above posts that the braking is way better, less grabby, more progressive, better feel, & even on a two hour twisty back road with a step descent 1.5hrs in which used to cook the standard 288mm disc...this time no cooking....total control....not even half way down with the pedal...

oh & remember I have the heavier golf estate (gsw) & this is with two people & a boot load of winter mountaineering gear..

 

[Sherifftruman]

So, I'm looking into doing this mod, but can't find thencslioer carriers. Putting those numbers (8V0 615 125A and 126A) are getting me no results in my usual online parts sources and at e-acca. Is there a different number this part is also known by or is there a source someone can point me to?