20 replies to this topic

[Minigirlracer]

Right - basically Im putting disc brakes onto my mini and had a big type servo and been told its quite a fiddly job installing it. A friend said it would be much easier if i got a remote type servo? Is this true? any one got any useful tips of getting hold of a remote type and fitting it....

Cheers

[taffy1967]

A servo will only give a softer feel on the brake pedal, so it's not really necessary.

But what age/model Mini do you own?

[bmcecosse]

Yep - thank your stars you don't have a servo - it's not necessary!

[rosco454]

Fitting the regular servo is straight forward,the fiddly bit is changing to the servo pedalbox as you have to do the clevis pins on the brake and clutch pedal to get the old one out.

[Pooky]

I drive a '89 Mini with a servo and my Mrs' '84 Mini with no servo and there's not a lot of difference in the braking to be honest. Her pedal is a little firmer and my fatter, grippier tyres probably help somewhat.

You'd be better spending your time and money on some decent pads and discs (I'd recommend MRA minis for quality made discs rather than Chinese copys) and keeping the system in tip top, well adjusted condition.

Not to mention the MUCH tidier, easier to work on, engine bay!

Edited by Pooky, 02 November 2009 - 10:53 AM.

[THE STIG]

Fitting the regular servo is straight forward,the fiddly bit is changing to the servo pedalbox as you have to do the clevis pins on the brake and clutch pedal to get the old one out.

you dont have to change the pedal box to fit the factory servo just the brake pedal ,done it several times

and you dont need a servo did not fit the servo's when they first fitted disc's to the minis in 1984

just gives a softer pedal, not extra braking power as some people belive

[Ethel]

There won't be a huge difference in performance between a direct and remote servo. The direct one has a couple of advantages in that it doesn't add extra fluid seals that can fail and it pushes both hydraulic circuits.

If you have a 7 inch servo connected to an engine that generates, even a modest, 10psi of vacuum; you have a force equivalent to an extra 5-6.5 stone pushing on the pedal. No matter how beefy your legs are that's going to push the pads against the discs harder, which is how brakes work.

If you can lock the wheels up then yes, you already have more braking force than you can use but you're going to have more control over the brake pressure if you're not standing on the pedal.

[Guess-Works.com]

On thing to add...

If it's a dual circuit braking system on your vehicle, and you do want to install a servo, DONT install a remote servo on the front brake system only... it's dangerous...

Effectively, you'll be driving a car with no rear brakes...

Before all those people add in "I have a remote servo and it's fine, the brakes work when tested at the MOT"... here's the reason why....

The servo is an "ASSISTED" braking mechanism, basically it means you don't have to press the brake pedal so hard to activate the braking system...
If you lightly touch the brakes on a 'non-servo' system, then the same hydraulic pressure is applied to both front and rear circuits, therefore actuating both front and rear brakes. On a properly connected servo system, again when the brake pedal is pressed, the servo then applies the same hydraulic pressure to both front and rear circuits and hence brakes...

If you only have the servo connected to the front brakes, then the pressure you apply at the pedal is transferred to the rear brakes, and the pressure applied by the servo to the front. This causes an imbalance of hydraulic pressure, and as you're not pressing the pedal so hard, very little if any at all braking from the rear of the vehicle...

When your vehicle is tested at the MOT, they are only tested axle by axle, therefore the MOT tester will press the pedal as hard as necessary to achieve the desired, it could be that the front brakes are effective long before the rear brakes are...

[Ethel]

Not strictly true, the piston furthest from the pedal is pushed by the fluid pressure behind it (which will be equal in an equal bore cylinder) and the servo wont operate until after that pressure has taken up all the free play in the system and closed the air communication valve. Thereafter the rear brakes will get the same pressure that they did before so will give the same braking effort. The front brakes will be doing more so there will be more nose dive meaning the rear brakes are likely to suffer from excess pressure causing the wheels to lock if anything.

Line pressure doesn't relate directly to braking performance. BL introduced the GMC227 stepped master cylinder that biases the pressure to the front as well.

We don't seem to think twice about improving brakes with fancy calipers or pads and how they will effect the proportioning of the braking effort either.

You could always use an inertia valve that senses the effect (weight transfer, that makes your rear wheels lock) rather than the cause.

[Cooperman]

Interestingly, the Innocenti Mini-Cooper 1300 I've just acquired has a dual circuit braking system, but the servo is only on the front brakes. The tandem vertical cylinder has a 0.7" bore, so one might assume that's not a problem.

[Minigirlracer]

Thank you for your answers. I've pretty much completed all the jobs needed to be done during the resto so am now ready to sort brakes out.

Any opinions on what I should do? I have the set up to convert the front brakes to discs with a servo (perhaps remote?) or do i just put the disc brakes on with no servo or keep my drums?


I have a 1300cc engine and just want to make sure that my brakes are good enough to make sure I can stop safely if anyone pulls out in front of me etc.... specially as dont want the mini to end up in a heap after all the work we've had to it


what would anyone recommend?

[Ethel]

Certainly use discs. You can always add a servo if want later.

[Minigirlracer]

Certainly use discs. You can always add a servo if want later.

yeah thats what Im planning to do - which means will be on the road sooner

[bmcecosse]

You really do not need a servo - try them without!

[Minigirlracer]

Yeah - they are quite expensive if they arent really required so gunna give it a go and see what its like before paying out and fitting a servo.