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R53 Front Brakes Upgrade – ‘Big Brake’ Options
Don’t know if anyone is interested on here, but I have set about this on my 2005 R53, so here it is. Long one I’m afraid.
This is an attempt to help those who want to upgrade their Gen 1 front brakes to the more effective Gen 2 front brakes (including the JCW alternatives). It deals with the calipers and carriers. There are many aftermarket caliper upgrades available but this sticks to BMW OEM. The manufacturers of these are ATE and TRW.
So What’s the Problem? Why Do It?
It is widely accepted that the Gen 1 brakes are unsatisfactory, particularly on R53 Cooper S models. The standard brakes lack stopping power, feel and are prone to fading with harder, more spirited use. The easiest and least expensive improvement is to fit the Gen 2 Cooper S front brakes.
Change the Rears?
The rears on Gen 1 and Gen 2 (including both JCW kits) use the same 259mm solid disc set up. Most advice is that it is not worth changing/upgrading the rear brake calipers and disc size, although clearly changes to discs and pads may be fitted. It is simply not worth the effort as the original R53 calipers are perfectly acceptable on the rear.
What is Involved?
Upgrading the Gen 1 front brakes to Gen 2 brakes involves changing:
• Carrier brackets
• Brake hoses
Gen 1 Standard Fronts
Exactly the same braking system was fitted to all Gen 1 MINIs, One, Convertible, Cooper and Cooper S, from launch to September 2006 (later for convertible), when the Gen 2 R56 model was introduced.
The fronts use a single piston sliding caliper system with a 48mm diameter piston acting on 276mm solid vented discs.
Gen 1 JCW Upgrade Kit
The JCW engineers picked a single piston sliding caliper with a larger 54mm piston and 294mm disc. This provided a bigger piston in the caliper for more ‘squeeze’ and a larger ‘swept area’. This was the set of front brakes that the R53 Cooper S should have had all along.
This kit just bolts on the existing hub and has the same ‘banjo’ hose fitting, so the standard R53 hoses are fine and can be used with the JCW caliper without modification.
The JCW kit was available with either a solid vented disc or a grooved and holed vented disc. The ‘holes’ were not drilled but formed in the casting process.
The JCW kit has red painted front calipers with the JCW sticker. The rear calipers were not painted red and neither the rear disc nor caliper was changed.
They were supplied with upgraded pads by Jurid for both front and rear brakes.
Not all cars with the JCW engine upgrade were fitted with the JCW brake upgrade - some had the JCW engine conversion but still with standard R53 brakes.
The JCW brake kit is no longer available new from main dealers.
Gen 2 Front Calipers
The Gen 2, from September 2006, uses a single piston sliding caliper with a 54mm piston caliper across the whole range. They have a standard electroplate finish. The brake hose fitting on the Gen 2 calipers is the ‘screw in’ type, not the ‘banjo’ type used on the Gen 1 calipers.
But the S carriers and disc size differs – see next.
Gen 2 Non S Discs & Carriers
The One, Diesel and Cooper have a 280mm disc. They all use the same carrier bracket fitted on both sides, non-handed (denoted TRW 15, stamped on the carrier). They have a standard electroplate finish.
Gen 2 R56 Cooper S Discs & Carriers
The R56 Cooper S has a 294mm disc – the same disc size as the R53 JCW kit. The 294mm disc is accommodated by using a different carrier bracket (denoted TRW 16 for the S, stamped on the carrier) to the non S models and they are handed left and right.
The S caliper carriers look identical but the sliding pins are set up differently with one of the pins having a rubber like part on it to stop the caliper sliding too much, thus making the caliper carrier handed L or R. They have a standard electroplate finish.
Front Brake Hoses for R56 Calipers
There is one significant difference with the R56 caliper when fitting to an R53 or any Gen 1 MINI. The brake hose fitting is a ‘screw in’ type not ‘banjo’. So you must use R56 front brake hoses when fitting the R56 calipers. They fit easily to the R53 models.
At the same time you may also wish to fit braided brake hoses front and rear.
Paint and Stickers
If you use the Gen 2 Cooper S electroplated items you won’t have the red calipers and JCW sticker. But you can get these professionally finished in red (or another colour of your choice) by the various companies that specialise in this. One such is Bigg Red. Or do it yourself.
It is also possible to buy the JCW stickers on eBay. Main dealers do not sell them. These should be affixed to the calipers after powder coating and then the whole caliper is lacquered to protect the sticker – make sure this is in high temperature lacquer.
The R53 has a relatively small brake master cylinder. So you may find the top of the pedal is softer once you have increased the size of the pistons in the calipers. It is not a major issue and does not impact on the enjoyment of the car.
This can be fixed. The larger R56 master cylinder does not fit on the R53. They are visibly different.
Gen 2 Cooper S or Gen 1 JCW Upgrade Kit?
So you can see that the Gen 1 JCW brake upgrade kit is basically the same as standard Gen 2 Cooper S brakes. The actual engineered solution is identical. Fitting standard Gen 2 Cooper S fronts will provide the same improvement as the Gen 1 JCW kit. It will be significantly less expensive, unless you can find a used JCW kit for sensible money.
1) Buy the R56 S calipers and carriers from a MINI main dealer
2) Buy the R56 S calipers and carriers from a factor or on-line
The R56 Cooper S prices are (June 2017) for new from main dealer, inc. VAT – they won’t give out part numbers, but hopefully these are the correct OE numbers:
Caliper N/S/F 18.104.22.1688.335 £256.01
Caliper O/S/F 22.214.171.1248.336 £236.00
Carrier N/S/F 126.96.36.1999.730 £80.00
Carrier O/S/F 188.8.131.529.729 £80.00
Hoses (front pair) £72.22
R56 Cooper S prices, from factors on-line – with the TRW part numbers:
Caliper N/S/F TRW BHW907 £67.46
Caliper O/S/F TRW BHW908 £67.46
Carrier N/S/F TRW BDA947 £44.96
Carrier O/S/F TRW BDA946 £41.36
Hoses (braided by HEL or Goodridge) £40 a pair.
So the TRW solution is £460 cheaper. Same product. No brainer.
You can buy the calipers and carriers used from any of the normal sources – breakers, eBay, forums.
When buying second hand parts you need the Cooper S caliper carriers but the actual R56 calipers are all the same 54mm piston type. So you can acquire any Gen 2 caliper and couple it with the R56 Cooper S carrier brackets for the big brake upgrade.
Discs and Pads
The disc and pad choice is down to you. Just make sure they are the 294mm items (for the Gen 2 Cooper S). There are many permutations of disc and pad available from a myriad of aftermarket manufacturers. Huge choice, many opinions, depends on what you are using the car for.
Last edited by NigelK; Jul 3rd, 2017 at 08:12 PM.