Do you really need a servo?

Do you really need a servo?

Author
Discussion

haynes

Original Poster:

370 posts

248 months

Monday 15th August 2005
quotequote all
On my 1990 cooper, which is now undergoing a complete rebuild, i'm quite keen to get rid of the servo. I'm running 10s with S discs & 4 pot calipers. I'll probably replace it with a single circuit system and S master cylinder with adjustable bias. It'll be used as a weekend warrior rather than a daily driver.

On the wife's focus if the engines not running then the brakes are alarmingly affected, but on a mini ther servo seems to contribute little to the pedal anyway. And most competition minis dont seem to use a servo. Also, I read in Vizzard's modifying your mini that the dual circuit system isnt as good as single circuit, is this the case?

fwdracer

3,564 posts

230 months

Monday 15th August 2005
quotequote all
I race a Mini on 10" wheels. Brake set up is standard cooper s disks and calipers and a single line system.
No issues with power or fade and the brakes are very effective.

Need to pay attention to pad material, as you'll need softer pads without a servo.

PatHeald

8,058 posts

262 months

Thursday 18th August 2005
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I have a 1275GT on 10" wheels, Lockheed calipers and no servo.

The pedal effort required is so excessive that I constantly fear that I'm going to bend the pedal or break the pedalbox.

I am going to experiment with soft pads. (recommendations, anyone?)

Something needs to be done, because pedal effort is certainly too high at the moment.

Incidentally, I have read that fitting 4 pot calipers reduces the need for a servo.

bjw970s

29 posts

248 months

Saturday 20th August 2005
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Noticed the comment about 4 pots... I would say it depends what 4 pots and what master cylinders you are running. Metro 4-pots don't get a good pedal, other specialist calipers may. I tried MG Metro calipers and thats what I found...

I have just bought alloy 4-pots and splashed out on a KAD bias pedal box with individual master cylinders which allows for a flexible set up.

I will see how it works but I know somone who rally's with the same setup and swears by it.

love machine

7,609 posts

241 months

Saturday 20th August 2005
quotequote all
I use well S Brakes and greenstuff pads on my 66. It will stop the thing but not like your repmobile. Cooper S brakes are pretty good if you ask me, I heel toe every gear and find that the thing slows up fine. If you're trying to drive it like a modern car, forget it.

I reckon feel is more important than pedal ease, if I had a servoed car, I'd take it off.

haynes

Original Poster:

370 posts

248 months

Tuesday 30th August 2005
quotequote all
Pedal travel worries me more than braking effort. To avoid excessive pedal travel, in the Bill Sollis book, he recommends a .75" bore master cylinder from an austin 1300Gt, although he recognises that they're pretty rare. I was hoping to use an S master cylinder, are these .70" bore and does that make much difference? Anyone know the bore of the master cylinder used on these late servos?

With a 296 cam and a straight cut box, you could never drive it like a repmobile. The calipers are minispares 4 pots btw.