14 replies to this topic

[Old Bob]

The Mini brake servo mechanism takes up a lot of space in a pretty crowded engine bay. I come from a high performance marque which managed without servo brakes for about 40 years (but they have them now) and braking was never an issue - to stop quicker you just pushed the brake pedal harder!

So, do I need the servo mechanism and do others dispense with it, or is it just me being difficult?

Bob

[colinu]

In my opinion the brake servo is not necessary. It gives the pedal a firmer feel (and bite might come earlier) but does nothing to increase the braking force. Personal preferance really - I have servo in my MPI, and none in my other Mini... and frankly I notice little difference between the two.

[tiger99]

How strong is your right leg? As colinu says, the server does not make the brakes any better, it just reduces the force you need to apply.

Servos can be slightly sluggish, so many prefer to do without them.

[Bungle]

my first mini a 1275 GT didn't have a servo but did have the 8.5 inch disks the mini i have now (1990 cooper) does have a servo and i have never noticed the difference

[Ethel]

Your insurers might choose to notice the difference if you junk it and don't tell them!

Unless you lock the wheels it will reduce your stopping distance.

[Old Bob]

Thanks Guys. No intention of deceiving the insurers although at my age they would probably never get around to paying a claim in my lifetime!

So, if anyone has done this (dispensed with the servo mechanism) do I keep the same master cylinder or go for something a little larger?


Regards,

Bob

[JVA10L]

I know this might sound odd but if you do away with the servo you should fit a smaller diameter master cylinder. The larger the diameter - the greater the force required to create the same pressure - mechanical fact!. Mini M/C's come in 0.7" and 0.75" and if possible you should go for the 0.7".

[lrostoke]

I switched from drums to 7.5 discs, kept the original master cylinder non servo , pedal feels fine, doesn't feel like I need legs like Arnold to push it.

[MrBounce]

Never had a servo on any of my Minis apart from my first one (a 1977 1000) which had an early GT servo & S discs. They all worked fine - my GT had the best brakes I've ever had on a Mini and they were standard 8.4" discs with no servo. It's not necessary in my humble opinion.

Edited by MrBounce, 24 February 2012 - 08:41 PM.

[Ethel]

A smaller bore also means more pedal travel, that's why the 1275gt also got a new brake pedal when it lost its servo and went dual circuit. The yellow band gmc227 would be the best option if you do replace it.

[bmcecosse]

Certainly no need for a servo on a Mini - up to you if you go for single or twin - personally I don't see any advantage of the dual. But DO get rid of the ghastly taper nose 'brake pressure equalising valve' - use the early pressure limiting valve. Mounted at the bulkhead it's easy to access it to modify the spring to set the rear brakes as you want them.....

[Old Bob]

Interesting points Guys - I obviously need to give this some thought. With regards front/rear bias, I fitted dual cylinders and bias adjustment in my track day beast and damned if I could notice any difference (except in the rain).

Bob

[Ethel]

Dual circuit is a requirement on road cars since '76. More potential to upset your insurers.

[racingbob]

never had one on my race mini

[Old Bob]

Certainly no need for a servo on a Mini - up to you if you go for single or twin - personally I don't see any advantage of the dual. But DO get rid of the ghastly taper nose 'brake pressure equalising valve' - use the early pressure limiting valve. Mounted at the bulkhead it's easy to access it to modify the spring to set the rear brakes as you want them.....

I am slowly getting there! I now have a yellow band gmc227 type twin master cylinder just waiting for a re-build kit and I am still looking for a good non servo brake pedal for the smaller clevis pin.

Question now is about the differences between the early rear pressure limiting valve which was already on the car, and the big brake pressure equalising valve which I also picked up along the way.

Can I simply pipe the two front (7.5" cooper brake calipers) direct from the new master cylinder and install the earlier pressure limiting valve on the rear line to the mini finned drums?

Thanks for your help people......

Bob