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The weakest link in any road car when it hits the track is usually the brakes (in all but the sportiest of sports cars and even some of those can’t cope), under normal road driving conditions we don’t use the brakes for long periods of time avoiding any significant heat build up. You certainly don’t have repeated heavy braking from speeds you’d lose your license for on a public road. My previous experience of owning a R56 Mini Cooper S tells me that the standard Mini braking system while fine on the road isn’t up to the rigours of track use, even on a relatively tame airfield autocross course the stock brakes were getting spongy.
Rear Brakes
Since the back brakes don’t have to do that much work on a front engined car I decided to refresh the discs and pads. Rather than use stock items I fitted EBC discs and Mintex pads. To finish the job off the stock flexible hoses where replaced with Goodrich braided hoses.
The replacement EBC discs have a dimpled surface that act as a wear indicators, once the dimples are gone it’s time to replace the disc!
Overall the swap was pretty painless although it took longer than most of the guides on the internet suggested, this was my first experience of working on the Mini having previously only worked on air-cooled VWs. It also marks what I suspect will be a love-hate relationship with TORX screws, I don’t see what’s wrong with a standard allen headed screw…
Front Brakes
The majority of the braking effort is always at the front end, so this required a little more than just replacing the discs and pads. There are a number of brake conversion kits for the R53 offering a variety of sizes and prices. I chose a kit from AP Racing giving 304mm discs and 4 pot calipers. The kit also comes with a set of Goodrich braided lines, enough fluid to bleed the system and a very extensive set of instructions.
The first job was to remove the old discs and calipers that will no longer be needed after the conversion. The discs just mount onto the hub (no bearings to deal with) which makes removal an easy process, apart from the dreaded TORX screw which fortunately is only torqued up to 10 ft/lbs. The new 4-pot calipers bolt directly to the existing hub, the old mounting hardware along with the calipers, discs and hoses are discarded.
The new front brakes won’t fit under the standard 17″ rims (which where trashed anyway having been used as parking aids by the previous “lady” owners) without some seriously large spacers so I had to swap to something else.
I decided upon a set of Team Dynamics Pro Race 1.2 (17 x 7) in gloss black shod with Toyo T1R tyres. The combination of the new rims and non-run flat tyres have shed a reasonable amount of unsprung weight from the car. The stock suspension is going to be upgraded later so the change from the rock hard run flats to something more compliant won’t be an issue, also since there isn’t anything similar to the mighty R888 (coming next year) in a run flat their time was limited.
What’s left to do?
All that’s left to do is bleed the system and bed the pads in, hopefully not too painful as I have a pressure bleed system. When stripping the system down I used the cling film over the neck of the reservoir trick to minimise fluid loss.
But….
While doing the front disc swap I noticed a fairly large amount of oil sprayed around the under side of the engine, a bit more investigation seems to suggest the leak is coming from the power steering system. Since I simply can’t afford to have the PAS failing mid-corner (imagine that happening going through Eau Rouge) I’m going to get the pump refurbished and replace the high pressure hoses. A job I could do without but better to be safe than sorry.