::: Improving Your VW's Brakes :::
When asked why he was so fast, Fangio once replied "more accelerator, less brakes". This theory is very true for track driving but unfortunately for those of us who use our cars on the Queen's Highways such a theory will end in tears. It is pointless and expensive to make our cars go faster if in fact we can't stop them ! VW brakes through the ages can best be described as variable with some being very good and others very poor. The following guide highlights the best ways to go about modifying a variety of VAG based braking systems.
The most common culprits for crap brakes are knackered parts. If your pads and discs are worn down, then they will heat up quicker, fade sooner and give poor performance. Before splashing out on expensive aftermarket parts ask yourself what condition the current parts are in. You may find that the most cost-effective way to improve stopping power is simply to renew the old parts. Standard brake parts are cheap (GTi discs £30 a pair and pads £10 a set) and available from most suppliers. There is no point fitting expensive pads if your discs are wafer thin or worse still, warped/cracked. Another sure way of getting an instant gain is to change the brake fluid.
Because DOT 3 & DOT 4 fluid is glycol based, it absorbs moisture over time. Moisture seeps in through microscopic pores in the rubbers, seals and hoses, and enters every time someone opens the master cylinder reservoir. Brake fluid is so hygroscopic (water absorbent) that leaving the lid off fresh brake fluid can ruin it overnight. This moisture contamination causes a drop in the fluid's boiling point which can contribute to feelings of brake fade during hard use. When a car's brake fluid is one year old, it contains 2.5% water. By 18 months, the water content can have moved up to 3% which is enough to lower the boiling point of the fluid by 25%. After a few years, the fluid can contain as much as 7% to 8% water.
If you have an old dub with a sketchy service history then chances are the fluid hasn't been changed for years. A simple brake bleed with £5 worth of fluid will remove any sponginess in the pedal and give you far better control over your braking. The job will take 30 mins max and even if you are concerned about doing it yourself your local garage should only charge £20 or so.
The second factor in stopping better is your tyres. Your car has forward momentum and in order to reduce this your brakes must exert a force in the opposite direction to your cars movement. They do this through the tyres. However good your brakes are they will be limited by the traction of your tyres. Fatter stickier tyres will give you the ability to brake harder before locking up. It is also crucial that you have pairs/set of tyres rather than odd ones. Odd tyres will give inconsistent braking performance at each corner, which in turn could lead to a spin as one-corner locks up far sooner than the others will. Before spending money on brakes make sure you have four decent tyres on the car, otherwise your uprated brakes will do nothing but lock the wheels and introduce you to the local scenery
The final factor that can often make a noticeable difference is cooling. Several companies offer various brake cooling-duct systems which pipe cool air to the disc - If you have a big bumpered car there are kits available to go in the fog light apertures which come supplied with all of the necessary pipework. These kits work by prolonging the time it takes before the brakes get too hot and begin to 'fade'. A good rule of thumb for mildly uprated brakes is: under hard use - the cooler the better. NB. This is sometimes not the case with exotic brake pad compounds so you'd do well to experiment. It is also worth bearing in mind that open spoked alloys are always going to let more air to the disc than standard steels or 16v bottle-tops...
The Mk1 GTi was designed primarily for the continent and was as such left hand drive. This meant that when they came to the UK the pedal box was on the right and the servo and master cylinder on the left. The Linkage between the two was flexible and twisted under load due to it's length. This helped contribute to the notoriously vague brakes associated with the MK1. They still stop the car but not before the driver has shat himself thinking that they won't. The car came with 239mm vented discs at the front and drums at the back powered by a 19mm master cylinder and a servo. This spec applies equally to the Mk2 Scirocco and to the Mk1 convertible GTi. The exception to this is the is the 16v Mk2 Scirocco which had discs on the back but there were only a few hundred of these ever made.
The Mk 2 addressed the vague brakes of the Mk1 by positioning the master cylinder and servo on the right where the pedal box was, thus shortening the linkage. The first 8vs came with similar 239mm vented discs at the front, albeit of a different caliper arrangement to the Mk1, but these were assisted by solid discs on the back. The early 16v also had this braking set up, powered by a 20mm master cylinder. The later (88 on) 16v got uprated brakes to cope with the extra power of the 139 Bhp power plant. This involved fitting larger 256mm vented discs at the front with a larger servo and 22mm master cylinder. The master cylinder was increased in size to match the larger diameter pistons of the calipers. 16v Corrados also received these improved brakes. The pinnacle of Mk 2 Braking came with the advent of the G60 (Golf and Corrado) which received the same basic set up as the 16v but with a different spacer bracket that allowed 280mm discs to be fitted. It should be noted that although the discs are getting bigger, so is the weight of each subsequent model and the heavier the car the more braking force is required to stop it. Later Mk2s, predominantly the G60s came with the option of ABS
The 8v and 16v Mk3 both came with 280mm front discs from day one (mainly due to their increased weight) and the 22mm master cylinder. The VR6 got slightly better brakes with 288mm discs items. Any cars that came equipped with ABS had a 23mm master cylinder. The Mk 3 Passat uses the Mk 2 16v set up.
The Polo G40 is the final model for consideration in this article and VW gave this 239mm discs and a 19 mm master cylinder but with drums on the back, which is not as much of a handicap as it sounds because of the car's minimal weight.
Uprated Discs and Pads:
The first after market step for modding your brakes is to fit uprated discs and pads. The pads are based on race compounds and grip the disc better as they have improved friction characteristics. The also have much better temperature tolerance and so will reduce brake fade. Such pads are available for all VWs and are a direct swap for the originals. They cost from £30 to £60 depending on brand. We have tried both Pagid fast road (£30) and Mintex 1144 (£45) Both are a great improvement over the originals and are worth every penny. There is plenty of choice in such pads so ask around and see what experience others have had. The Pagid ones are the best we have tried but they are very hard and eat discs quicker than other pads. The Mintex ones are excellent at high temperature but no better than standard when cold. Kevlar based pads are available which offer excellent performance as they leave a deposit on the disc which means you get a kevlar/kevlar friction point. They are cheap but very soft and so you will get through them quickly and they leave a filthy brown deposit on the wheels.
We would recommend fitting uprated discs at the same time as performance pads to maximise the improvement in braking. These have holes or grooves in them (or both). The purpose of which is to remove gasses, produced as the pad disintegrates, from between the disc and pad. They also scrape the surface of the pad to remove any glazed material. If the pad gets too hot its chemical composition changes and it ceases to grip the disc. The grooves/holes remove this glazed material from the pads. Porsche have thoroughly tested both drilled and grooved discs and conclude that the drilled ones are better. They were unfortunately unable to come up with a reason why, so ask around and see what experience other people have had. We use drilled and grooved combination discs which work very well (Sportline £50 a pair). The discs can cost from £50 to £120 depending on brand. Some companies (Dubsport) offer zinc-plated discs which do not corrode like regular steel ones but offer no performance advantage over similar steel items. These are aimed at people who like their brake conversions to look good behind their wheels. Uprated discs and pads are compatible with all the mods listed below and they are an ideal place to start. They are also only slightly more expensive than standard parts so consider uprating when you come to replace your worn out brakes instead of just using standard parts.
Replacing the standard rubber hoses with braided ones is a very common mod and applicable to all cars. The rubber hoses can bulge under severe braking which reduces pedal feel and thus braking control, the braided hoses do not bulge and transmit the force transmitted by the fluid far more effectively - thus improving pedal feel. This mod will NOT make your car stop any quicker but it will help you control your braking and give you far more confidence 'on the limit'. Various kits are available (Goodridge, Aeroquip) and will cost about £50. You will need to do a complete brake bleed and will probably have to change some of the copper brake lines at the same time as the copper unions tend to deform beyond repair when you undo them. Whilst these are inexpensive they will add hassle-factor and time to the job, so bear it in mind. Cars with rear drums will require a four hose kit, whereas cars with rear discs will require a six hose kit. Make sure you get the right kit for your car as the hose lengths do vary.
Mk 1 GTi :
The most common mod for the Mk1 is to replace the servo and master cylinder with those from a post 88 16v (larger servo and 22mm master cylinder). These reduce pedal travel and reduce the amount of driver effort required when braking. It will not make the car stop any quicker but will help you control the braking better as well as reassure you that the brakes actually work thus reducing the number of brown trouser moments. The parts are a direct swap but a complete brake bleed will be required at the same time. Volks Bits do both for £75. I would recommend using a new master cylinder and servo rather than second hand ones as the seals on the master cylinder deteriorate with age and mean that it will leak fluid during use. The next specific mod to do is a rear disc conversion, which uses parts from a Mk2 GTi and a Scirocco 16v handbrake cable. This is a bolt on job but costs about £350. I would not bother doing this unless you have already uprated the front brakes as the rear brakes do very little. It is more important to uprate the fronts first. Front wheel drive, a light car and an engine at the front mean that there is very little weight over the rear under braking and so the load proportioning valve prevents too much braking force from going to the back. Obviously the comments about discs, pads and braided hoses apply and these would be the first things to attend to. If you want to take it further it is possible to buy a spacer bracket (C&R and TSR, £90) which spaces the caliper further from the hub and allows 285mm discs to be fitted. It is also possible to fit the 256mm set up from a Mk2 16v by using a spacer bracket and retaining the original calipers.
Mk2 Gl and Drivers:
If you own a non-GTI Mk2 you will probably have suffered brake fade at some point. This is because the standard discs are solid (not vented). This means that they get hotter quicker and thus cause brake fade. You can fit the vented GTi discs to these cars without any other mods. They are a direct swap but because they are fatter you must fit the GTi pads (which are narrower) at the same time otherwise the combo will not fit in the caliper. This mod does NOT work for 1.3s and 1.0s (yes they did make a 1L mk2) as the calipers are too narrow to accommodate the thicker discs. Further to this you could bolt on rear discs from a GTi.
If you have an early 8v you can fit 256mm discs or 280mm discs but it is more involved than with the later models as the caliper carriers form part of the hub. This prevents a spacer being used or a different caliper carrier. You will need to get a pair of 16v hubs, caliper carriers, and calipers (£200 from a breakers) and bolt these on. You will also have to change the ball joints as the earlier cars came with a slightly larger ball joint which will not fit in the later hubs. The hubs and other parts can be found on Golf/Corrado 16vs (post 88), Mk 3 Passats with either the 8v or 16v engine, and anything with a G60 engine. If you want 256mm discs then you must use the caliper spacer brackets from the 16v but if you want larger 280mm discs then you need the G60 brackets. These are harder to come by as G60s are rarer but you can get them from Autocavan for £90 a pair. These brackets fit on the 16v set up so you do not need the entire G60 set up. If you fit the 16v/G60 brakes then you will also need to fit the later 22mm master cylinder otherwise pedal travel will be excessive due to the larger caliper piston. You might want the larger 16v servo but this is not essential. Both master cylinder and servo are bolt on mods. Whilst the bits are off the car I would recommend replacing the wheel bearings at £15 a side. This is cheap compared to the cost/hassle of taking everything apart later when you discover the bearings are knackered.
It stands to reason that the 16v (post 88) set up can be converted to 280mm by just fitting the G60 spacer bracket and the larger discs (the pads are the same). Some companies will chop the caliper carrier off your early 8v hubs and weld it back on with a spacer. This allows discs up to 280mm to be fitted and you will retain the original calipers, ball joints and hubs. You will also not need to fit the larger master cylinder (unless you want to). This conversion for the late 8v is easier as you can retain the existing ball joints and the hub assembly differs in that the caliper carrier and hub are separate thus allowing a spacer bracket to be used to accommodate larger discs (speak to C&R). As always you can fit uprated discs and pads with any of these conversions. Bear in mind that big discs only fit behind big wheels. The general rule (depending on the exact cross section of the wheel) is that you will need 14inch wheels for 256mm discs and 15 inchers for 280mm discs.
If you are really serious about stopping then several companies such as AP and Wilwood offer complete brake upgrade kits but at £1,500 a kit this is rather pricey and you probably couldn't put that much stopping power through your tyres. Such kits give you 4 and 6 pot calipers (as opposed to the std 1 pots VW provide) combined with 330mm discs and are available for the Mk2 and 3. You will need at least 16 inch but probably 17 inch wheels for these. You can also fit items such as adjustable bias valves to allow fine adjustment of braking force to the rear of the car but unless you hit the racetrack regularly there are probably better things to spend your folding on.
As for the rear Mk2 brakes, there are uprated discs and pad available but the back brakes do so little that these would merely be cosmetic mods (not that this should deter you). In fact chances are your time will be spent getting the back brakes working rather than modding them. Because they do so little they seize easily which not only dampens braking performance but fails the MOT. This is most common with the pre 88 models and VW revised the design of the calipers for the later cars to eliminate this (They didn't quite succeed but it was an improvement). Usually the only solution is a new caliper and we would recommend replacing these in pairs to eliminate the risk of inconsistent braking from each corner. (Bear in mind - It is possible to fit later MK3 calipers where the hand brake mechanism is internal and not prone to seizing - sometimes a cause of seized calipers. If you fit these calipers you will also need to fit the late MK2 handbrake cables, which are longer and run under the caliper instead of over the top)
Before parting with cash it is worth experimenting with some over zealous braking as this has been known to free them up especial when combined with some anti binding agent. It is also worth removing them from the car and trying to free them up by hand (you will need a brake wind back tool for this). Take care when fitting the new calipers to get them the right way up (people have been known to put them on upside down). The bleed nipple goes at the top (otherwise you would never be able to bleed the air out of them).
Unfortunately this car comes as standard with 13inch alloys which prevents the fitment of larger discs. If you were to fit larger discs then the wheels would have to be the first thing to go. It is wise to start by uprating the discs and pads and then fitting braided hoses. You can also fit a larger 22mm master cylinder but not a large servo as there is not enough room in the engine bay to accommodate this. VW sadly fitted the brakes to this car as an 'afterthought' so getting a dramatic increase in stopping force is tricky. However brake bleeding, using quality parts all-round and getting the rears set up well will show a marked improvement!
We have not covered the fitment of these mods in any detail, because the brakes are a safety-critical part of the car and whilst all these mods are simple to a half-competent mechanic, we would recommend that you consult your trusty Haynes manual or an experienced friend/professional mechanic if you are unsure about fitting your brakes.
It is very popular now to have lacquered brake calipers (a la Porsche, Brembo etc) as they look smart and are easy to clean for shows. When the parts are off the car it is an ideal opportunity to lacquer the brakes. There are various kits available and I would urge you not to use them. At £25 they are very expensive and convoluted in their application. One of these kits would only do one pair of brakes properly. Our top-tip is to go to your local Les Smith and buy a can of Car Plan engine Lacquer. This costs about £4 and is enough to coat 10 brakes thoroughly. Halfords do a similar product. It has a hard gloss finish and is chemical and temperature resistant. The parts can be lacquered on the car but this is a bit of a botch so we would recommend striping the parts down as far as possible and then cleaning them thoroughly. The lacquer can then be applied with a regular brush taking care not to apply it to any mating surfaces or moving parts, especially the pistons or seals. If you remove the calipers from the car all together take care to seal-off the brake hose hole with a suitable nut…
Disclaimer : Matey-Matey accept no responsibility for any of the information contained within this document or the accuracy thereof. It is intended as a helpful guide and is solely based on personal experience. The authors also wish to stress that the methods highlighted are centred around personal opinion and there may be other equally credible ways of performing this conversion.