“PLAQUETTES DE FREINS” (BRAKE PADS)

One commonly asked question is in reference to brake pad types best to use, expected lift and characteristics etc.  Especially in reference to race applications, so I shall try and outline the pad types we keep and their “essentials”.
With all things there is always a compromising area, and brake pads are no exception.  Main usage or priority should be the deciding factor, the shortcomings at either end of the spectrum should be tolerated and given due consideration. 
A major part of braking done on road cars is around town, or short distance, multi stops.  The next is braking from cruising speeds, be it when encountering traffic build up, or slowing on off ramps.  The brakes are rarely used in severe and continuous fashion – braking hard from high speed as fast as possible for protracted periods (similar to face track use).  The type of pad to be used should be selected bearing these factors in mind.

For road use I have rarely recommended anything other than good quality standard pads, Mini Spares keep both genuine Rover supplied items plus those manufactured by Don International (a very major OE equipment supplier) of Mintex M121 pads.  I have always found either of these pads to be very good.

Having a harder (higher temperature range) pad would give the odd heart stopping moment as they take longer to reach their operating temperature – totally unsatisfactory, especially when braking suddenly at motorway speed after a period of high speed cruising.  The brakes will be relatively cold, so quick warm up is crucial.

For those that do more miles in “squire and dab” country, then the characteristics required of the pad are slightly changed.  The main factor here is heat build-up, as there will be less time for the brakes to cool.  A pad with a slightly higher temperature range is needed yet with a similar co-efficient of friction to the standard pad – necessary to help avoid the brake efficiency overcoming the tyre to road adhesion.  Wheels that are locked up under braking are grossly incapable of slowing the car down rapidly.  The Mintex M171 pad type is the one to use here, and probably as “hard” as you should go if the vehicle is used mainly as a road car. This pad is also preferred by some racers – mainly sprints and hill climbs.  For the faster circuit cars they tend to fade too early.

From here on, the pads should only be considered for rally/race applications
The Ferodo 2495 is the next type, and really is a very good race pad.  It has the quick warm up characteristics of the M171, resists fade almost as well as  a DS11, and falls somewhere between these two in wear rate.  They are of most benefit to those where standard ‘S’ type brakes are “de riguer” according to the regulations.

Then there is the much revered DS11.  The proverbial “house brick” pads.  These pads need the correct bedding in procedure to make them perform correctly.  The biggest problem is actually getting them up to working temperature, especially as a race Mini doesn’t weigh too much!  Within the temperature envelope reached by most race Minis the pads tend to glaze over, greatly reducing their efficiency.  This can be remedied by removal and

attacking with emery cloth – hardly the most desirable situation – you can pay your money and make your choice!
Now the most technically advanced pad type currently available – short of carbon/carbon brakes that is.  Carbon Metallic pads.  Designed and developed the States, this pad is the “crème de la crème”.  It has an enormous heat range potential, superb co-efficient of friction and exemplary wear rates.  Basically it encompasses everything from M171 to DS11, yet does it all far better and for longer.  There is a bedding-in procedure to maximise their potential but once done there are no further problems – providing either new discs, or unblemished used discs are used.  During the bedding-in procedure the pad actually imparts particles onto the disc – thus coating it in a fine layer of carbon.  This should not be cleaned form the disc at any time as long as Carbon Metallic pads are used.  Ds11 pads have a friction co-efficient of .35 maximum  Carbon Metallic “Blue” pads develop a figure of .50!.  The hitch?  None at all.  Although a little more costly initially over the other pads, it is definitely money well spent at the end of the day.

Carbon Metallic pads cost £50.53 for the Mini Spares alloy 4 pot calliper or Metro callipers.
The 10” wheel or 7.5 ‘S’ disc variety cost £45.24

… AND THEN THERE’S BRAKE SHOES

For those stuck with drum brakes – things are not as dire as they appear.  The standard drum brake system can be made to work very well – the secret is regular maintenance.  As far as types of shoes available, there is a small selection.
For the front, apart from standard bonded shoes, we stock an aftermarket shoe set that appears to be marginally better.  These are manufactured by a company called Sibrex and are rivetted linings.  These seem more than adequate for normal road use, however they tend to fade out when pressed hard by the more – erm, ”progressive” driver.  The only readily available alternative is the Mintex M20 lined shoes.  These are basically the equivalent of the old Ferodo VG95 lining, and provide fine stopping power from the basic drum set up.
At the back, I seriously doubt that anything other  than good quality standard shoes are needed – they do very little.  Severe braking at the back creates some very entertaining situations – totally undesirable on the road.  However in most racers I would recommend using M20 uprated shoes.  I realise that the backend of a racer probably does less work due to less weight than a standard car – but the M20 shoes do not grab when the brakes are suddenly applied  This obviously helps stability when braking hard into corners.
All prices are per “axle” set.  A surcharge of £1.18 applies to the standard set.
Prices include VAT.

AND WHILE WE’RE ON TRHE SUBJECT OF BRAKES ..

We have been asked all kinds of odd questions related to braking problems, but by far the most common ones are two regarding disc brakes and two regarding drum brakes   Both usually associated with recent application of either an entire disc brake set up or the fitting of new shoes to drum brakes.
Following fitment of new shoes on the front of a drum braked car, the usual problem encountered is that “they seem OK. for a while, then I get a lot of pedal travel again”.  Solution number one is that the adjusters MUST be turned in the direction of rotation of the wheel.  This means clockwise on the right, anti- clockwise on the left.  If the adjustment is made in the opposite direction the concentric cam will adjust the shoes up to the drum – but will be forced back by the action of the springs on the shoes.  Effectively de-adjusting the brakes.  The other concerns the lack of the springs that holds the wheel cylinder.  If this occurs the result is a lot of pedal travel as the pistons are pushed out to meet the shoes – hence pumping the brakes brings the pedal “up”.  If these springs are missing it is obviously highly recommended to fit them. 

Grafting disc brakes onto a Mini previously adorned with drums is a relatively straight forward swap.  Unfortunately the same “poor pedal” syndrome is suffered.  Going all around the houses to ensure that the system has been bled properly, all other valves and cylinders are 100% etc.  The problem is – believe it or not – that the callipers have been put on upside down!  The bleed nipples need to be at the top to allow the air out, not at the bottom to allow the fluid out!  Putting this right immediately cures the problem.  Long pedal travel can also be caused by using the standard brake master cylinder.  The length of the pedal to cylinder push rod is the problem here.  The ‘S’ one slightly longer - once again taking up the play causes a low pedal.  The original ‘S’ brake pedal was also different.  It was slightly thicker material and cranked higher up to help compensate for the extra travel experienced. The easiest solution is obviously to lengthen the push rod slightly.

Mini Spares have recently released a kit with comprehensive instructions to help those people wishing to alter their brakes to Metro four pot callipers.  The biggest inconvenience is the dual line feed employed on the Metro.  The conversion kit explains how to modify the callipers to single line feed, and contains the relevant parts to do the job.
C-AJJ4024         Conversion kit        £34.08

All Prices Are Historical

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Importation rules regarding vehicles are very specific: Only those over 25 years in age may be brought in to the USA without compilance to Federal Motor Vehicle Safety Standards (FMVSS).