Optimising brakes

[rolesyboy]

I fitted grooved 7.5 discs and green stuff pads to my Mini years ago. The brakes always work fine but they have never impressed me eg if you went to pull up hard they stop you but hot or cold they lack ‘bite’. I even fitted carbon metallic pads a while ago.
I am about to overhaul the brakes and I would like to improve them. Maybe I am spoilt with modern cars but I am sure I can improve them and I wondered what tips people have on optimising their brakes. Swiftune and the like seem to have absolute confidence in their set ups on a track so I figure if they can do it what can I do to sharpen mine up?
I can’t recall what diameter rear cylinders I fitted years ago but if they are the basic Mini ones would that make a noticeable difference?
There is no air in the system, they stop ok, it pulls up in a straight line but I am sure they can and should be sharper
Grateful for peoples suggestions or ideas. Cheers. Mark

[Spider]

I found the single best improvement was moving to 4 pot calipers, they give you a bigger pad surface area.

[rolesyboy]

Thanks Spider. I’m not against that idea but I would like to optimise the standard ‘S’ set up.
I didn’t mention that I fitted aeroquip hoses all round.
I have a feeling it may have a standard brake pedal as 15 years ago I didn’t know an ‘S’ was any different. Guess that just changes the level of effort required as opposed to how sharp they are???
What tips have people got on bleeding the system, adjusting rear shoes etc
What do Swiftune etc use? 4 pots ?
Cheers

[GraemeC]

I don’t think the ‘S’ pedal does anything but change the height of the foot pad - offers no additional mechanical advantage / lever ratio.

Do you have a servo fitted?

[Polarsilver]

To be fair to Spider you did ask what people are doing optimising their Brakes .. so his 4Pot suggestion is valid .. back to your car what about the rear pressure bias valve when was that last looked at .. is it correct valve relative to the size of rear wheel cylinders in use ? .. old brake pads & rear linings can become next to useless ..i would take out the Servo if fitted & try the car without..Brake Fluid worth replacing.

[rolesyboy]

Thanks Polar. Spider’s suggestion is appreciated (& I may well fit some as soon as I am satisfied the rest of the standard system is operating as well as it can)
The brakes have always felt similar from day one so I suspect fluid is not an issue (although I will change it anyway)
I have never fitted the servo.
Rear bias valve- I can’t recall if it was new but it probably was at the time. I am not sure if it is correct relative to the rear cylinders though. How can I tell if they are the right components? I reckon that could potentially be the game changer.
What are the correct specs for an S please?
Cheers
Mark

[Oneball]

I find on the race car that rear brake adjustment is critical if they’re not up you get a nasty pedal. I also have them adjusted to absolute minimum on the bias valve so it’s the travel that’s affecting feel rather than the braking force they provide.

[Peter Laidler]

This and similar brake related threads reminds me of when I was helping a pal to video-alarm his house, garage, garden and out-buildings. Instead of installing an all matching, compatible, complete kit - as it were, he used scanners from X, cameras from Y and so on. Eventually..... anyway, while the bits were good, he could not get them to operate as a whole. Eventually, he had to go back to basics and start again.

Just like some of these brake queries we read about.

There are so many variables of master cylinder bores, wheel cylinder bores, bias valves loads that without a great deal of experience are barely compatible. Sometimes, using this with that and something else - some call it mix 'n match - you can end up worse off than when you started and certainly, with a dodgy pedal!!!!!

I was going to say what I would do, from a mech engineering, and physics point of view with a bit of volumetric maths thrown in to calculate the bore size ratios. But playing with all these mini brake variables on a road car......, not for me i"m afraid

[Fanfaniracing]

On my Car, basis is a 62, 997 Austin Cooper, i fitted 7.5 S Brake Discs, rebuild the Calipers myself with Minispares Seals and S/S Pistons and a Minispares Mk1 Servo. All with Braided Brake hoses.

What i did on my setup is that the Servo only operates on the Front Brakes.

I learned this Trick from my old Master and it works perfect.

Plenty of Brake Power to stop the 8 Port

Speaking to the Swiftune Brakes: i had the opportunity to examine the Brakes of Willow 3 at the Goodwood Revival last Weekend and they look Standard about the Discs and Calipers. Brake Pads could be the Carbon Metallic ones he sell on his Page. Brake master was something AP Racing
No Servo fitted...

[GraemeC]

I think a servo will give more initial bite, but less feel.