mk4 Jetta, Golf, New Beetle big brake upgrades

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Difficulty 3/5  The more complex brake conversions are 3/5, the easier ones are 2/5.

Introduction

related links:  1000q: TDI conversion to TT/R32 spindle and LCA and  1000q: detailed "how to" swap big brakes onto the non TDI spindle 
for mk3 VW see 1000q: big brake kit options

The brakes on the a4 platform can be upgraded to larger rotors and/or pistons to give you better braking but you may need to use some non-TDI suspension parts, see below for detailed information.  Before you spend money on big brakes, try using different brake pads, it may give you better braking feel, and it's cheaper and might be all that you want.  Also make sure that the brake fluid is flushed, clean, and has no air bubbles.  If you have to press twice on the brake pedal to get sufficient braking action, there may be an air bubble in the lines.  Also remember that greater braking power is totally useless without tire traction and proper suspension/balance to take advantage of more braking.  Below is more detailed information on big brake kit conversions.

Because it is so important to know some general braking info, please read 1000 answered questions: brake FAQ and busting big brake myths.  It includes brake pad/rotor info applicable to all cars, such as race vs. street brake pads, drilled vs. plain rotors, which direction the brake slots should point, and lightweight rotors.  It may also show you why you may not want a big brake upgrade!

The suspension is another major factor in braking performance.  A worn suspension changes the way the brakes will behave.  A4 VW TDI suspensions are soft and after age and use, get even softer.  New struts, strut bearings, mount, control arm bushings, and anti-sway bar bushings in the front will do a lot to restore the handling and braking bias on your VW.  The rears need new mounts and struts.  If your car feels like a heaving hovercraft then a big brake kit won't do much.  See 1000q: strut install 1 and 1000q: mk4 strut install 2 for "how to" articles on replacing the struts and some of the bushings.

Disclaimer: Before you attempt any brake work on your car, refer to the factory service manual and follow all precautions.  Any and all information presented on this website is superseded by the official service manual and is not a substitute for the services or advice of a certified professional mechanic.  See the TOS Agreement for the full legal disclaimer.  If the brakes are faulty or not working correctly, tow it to a mechanic and do not attempt to drive the car.  Faulty brakes can result in an accident or loss of control so have your local garage do it if you're not qualified to work on the brakes.

Big brake upgrade FAQ for Jetta, Golf, New Beetle

The brakes on VW TDI and gasoline VW with the 2.0L engine are part of the spindle (steering knuckle/hub assembly) and can't be separated.  To upgrade to larger brake rotors or calipers, you must first replace the spindle which includes larger, removable brake carriers, and then you can mix/match the larger rotors/calipers/carriers.  Your original "FSIII" front brake calipers on the TDI cannot be reused in the larger brake kits (they were also used on the 2.0L engine cars).  The caliper is physically smaller, does not have a removable carrier, and uses a small brake pad.  Your front conversion must use the "FN3" used on all 1.8T/VR6 cars which includes any special edition 337/20th anniversary, GLI, GTI (except the golf R32 which uses a 2 piston caliper).  If you already have a 1.8T/VR6, you just need to change the rotor and carrier.

All modern VW passenger car brakes use floating calipers.  These are calipers that float and move on slider pins.  The piston is on one side only and it lets the rear caliper double as the parking brake.  The advantages are: simple, light, and cheap.  Fixed calipers are in a fixed position with pistons that push on each side of the rotor.  These tend to be heavier and more expensive and are found on more performance oriented car's 4 or 6 piston calipers and the aftermarket kits linked below.  They cannot be used on the rear with the stock parking brake mechanism since the caliper is different.

Pictured below are a few brake parts.  If you want +1 size larger rotors/calipers, you want a spindle/hub, carrier, caliper and brake dust shield.  Other parts are pictured for reference.  These parts can also be found on the GTI, 337, GLI, 20th anniv, 25th anniv, etc, the spindle is all the same.  A direct bolt on spindle should be from the 1.8T or VR6 engine cars, all you have to do is remove your existing spindle and press your existing hub and a new wheel bearing into your 1.8T/VR6 replacement spindle.  Some GLI/special ed. 1.8T/R32 Golf use an axle bolt instead of a nut.  These have slightly shorter axle splines.  Since you're putting your existing hub and a new wheel bearing into a 1.8T/VR6 spindle, you can use any 1.8T/VR6 spindle.  You must use a hub from a car that uses axle nuts if your car has those or axle bolts if your car has those.  I recommend new wheel bearings and your existing hub on the spindle.  You cannot use Audi TT or VW Golf R32 spindles unless you also modify the ball joints to fit the mk4 lower control arm OR add TT/R32 lower control arms (LCA) and the necessary supporting pieces.  

The big advantage of converting to the TT/R32 suspension is adjustable camber on the LCA and bigger/stiffer bushings.  Also note that although you cannot use the TT/R32 spindle without modification, it has nothing to do with the TT brakes, they are direct bolt on to the 1.8T/VR6 spindle.  See 1000q: TDI conversion to TT/R32 spindle and LCA for a how to and more details.

Because of the need to convert the spindle to 1.8T/VR6 parts for big brake kits, the most basic upgrade would be using performance brake pads to change braking feel and is suggested before trying larger/more expensive brake conversions.  Also read 1000q: basic brake tips and busting big brake myths to see if you really want/need a big brake kit since your suspension probably needs work.  If you choose a conversion and remove the spindle, inspect the sway bar bushings, wheel bearings, ball joints, LCA bushings, and tie rod ends too.  Whether or not to replace these components is up to you.  The stock sway bar endlinks are pretty good and don't wear out much.

Lastly, the stock brake bias is about 70/30.  Adding larger brake components and using more aggressive pads/rotors will change this.  A +1 or +2 size larger rotor to a TDI in the front only will change the bias by about 3-5%, acceptable for a street driven car.  Pads will also effect this.  During light braking, the electronic brake distribution (standard on North American TDIs) will apply the rear brakes more than the front brakes.  This reduces dive and distributes brake force more evenly.  During hard braking, the ABS will prevent wheel lockup and the bias shifts toward the front.

Upgraded brake/rotor chart for mk4 TDI Jetta, New beetle, Golf

+1 size:   If you still want more braking power after trying more aggressive brake pads, first get 1.8T or VR6 brakes and spindles with their removable carriers.  These stock brakes have slightly larger front rotors and pads.

+2 size: The next size larger brakes involve swapping the removable brake carrier from the 1.8T/VR6 spindle for Audi TT brake carriers.  This moves the brake caliper out and will let you use larger Audi TT brake rotors.  This costs about $800 plus minimum 16" wheels for brake clearance.

+3 size:  The max size OEM brake upgrade is from the 6 cylinder Audi TT and VW R32 golf.  the Audi TT VR6 quattro and VW R32 are all wheel drive and used 6 cylinder engines.  As a result, they were heavier than the TDI and using their brakes will be overkill for most TDI drivers.  The larger, heavier brake components will reduce handling/comfort, acceleration, and mileage.  If you don't have enough tire traction/suspension to take advantage of bigger brakes, you will not increase braking performance vs. a smaller kit.

You need at least 17" wheels and possibly 18" wheels because some 17" wheels may not have sufficient inside clearance to clear the brakes.  The TT/R32 use 2 piston calipers which take up less space but aren't as large as 4 piston calipers found in many other performance cars.  If you want 4 piston calipers, you have to use non-VW brake kits.  For best results when using brakes this large, a rear brake conversion is also recommended to keep the brake system balanced but in a street driven car, the difference may not be noticeable.  This costs about $1000-1300 plus minimum 17" wheels for brake clearance, some 17" wheels may not fit.  

+3 size and larger aftermarket:  There are even bigger brake kits available from various vendors that use Porsche Boxter, 993, and Cayenne calipers.  Some have custom rotors, so you have to buy replacement rotors from the vendor.  These typically use a caliper mounting bracket to attach to the 1.8T/VR6 spindle and some need wheel spacers.  There are also kits from Brembo and Stoptech listed below.

Below is a table organized by ascending stock brake sizes and the cars that they are found on.  Below is a table of aftermarket caliper kits and parts.  To give you an idea of what you my need, here is a picture of autotech's front and rear brake kits.  The TDI may need rear dust shields if you increase the size too much.

OEM Specifications and parts

VW 1.4 (euro only, -1 size)

VW 1.6, 2.0, TDI

(Note: To upgrade to most front aftermarket or OEM brakes you need to change the hub carriers (spindles) to 1.8T or VR6 specifications, DIY kit available from dealer, Performance cafe's full TDI conversion kit to 1.8T/VR6 spindle (with hubs, bearings, ABS rings, bolt hardware, and calipers of your choice), ECS tuning's full TDI-1.8T/VR6 spindle conversion kit (with hubs, bearings, ABS rings, ball joints, spindle/housing)

VW 1.8T, VR6 (+1 size)

Audi TT 1.8T 180hp FWD and AWD coupe and roadster (+2 size)

Audi TT 1.8T (225hp AWD coupe and roadster) (+2 size, also larger in rear)
VW Jetta/Bora GLI
VW GTI: 20th AE, 25th anniversary ed., 337
VW Golf and Jetta/Bora 4 motion
VW New beetle VR5

(Note: Above model front calipers are the same as stock 1.8T/VR6 calipers but are some are painted red.  They are bigger because they use a larger carrier/rotor.)  (Some cars were also 6 speed and may have used an axle bolt.)

VW Golf R32, New Beetle RSi, Audi TT 3.2 V6 (250hp) (+3 size)

Aftermarket caliper/rotor components: Front

Aftermarket caliper/rotor kits: Rear

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