18 replies to this topic

[nmt_oli]

right, im thinking of ditching my servo. seems easy enough to throw away old system, and put a new master cylinder in, but the non servo masters only have one outlet rather than two, do i just need to use a T piece?

I am also removing the std proportioning valve and replacing it with an adjutable bias valve.

is the servo'd master cylinder the same in terms of fluid displacement to the non servo cylinders, or is there a difference? will be running KAD 4 pots if that matters.

[Ethel]

Can't see why you'd want to junk the servo.

Mini's haven't had single line braking systems since before 1976.

If you opt for an adjustable valve you'll need to rearrange the plumbing into a front rear split.

Very likely the master cylinders will be different bores. The twin cylinder immediately prior to the horizontal servo setup has two different bore sizes in the one cylinder.

[minislapper]

Not sure you're insurance company would like you messing with the brakes either! Especially as, in effect, you're going backwards in safety measures in their eyes!

[Guess-Works.com]

A servo has nothing to do with safety, and I'd say a non-servo system tends to be more reliable.

What you need to do is replace the servo and actuating arm on the pedal for a split system master... http://www.minispare....aspx?pid=36659

Don't remove the bias valve

However if you're going for a single line system, then yes, you have a three way adaptor on the bulkhead which takes the feed from the tin master and then splits it into two, one for the front and one for the back... This then needs a regulator value ( usually on the rear subframe ) or as you say a bias adjuster which will need to be set so your arse does not pass your nose when braking.

[nmt_oli]

Can't see why you'd want to junk the servo.

If you opt for an adjustable valve you'll need to rearrange the plumbing into a front rear split.

servo is extra weight, and a lot of people have said unless its in good nick (mine is unknown, car has been off the road for 3 years) then it doesnt do much anyway, as the vacuum resevoir is so small.

brake alreasy are front rear split- its a 92 car. plumbing isnt an issue any way, im replacing every single line on the whole car.

Not sure you're insurance company would like you messing with the brakes either! Especially as, in effect, you're going backwards in safety measures in their eyes!

I don't think the insurance is going to like my car at all, i cant think of many things on the car that will be std when im finished.

[nmt_oli]

Don't remove the bias valve

However if you're going for a single line system, then yes, you have a three way adaptor on the bulkhead which takes the feed from the tin master and then splits it into two, one for the front and one for the back... This then needs a regulator value ( usually on the rear subframe ) or as you say a bias adjuster which will need to be set so your arse does not pass your nose when braking.

Thanks for the link guesworks, very useful- only found the single line cylinders.

why shouldnt i remove the bias valve is i have an adjustable in line one ready to go on? would you say its better to go for the twin cylinder, or the single one with a split? the single ones a hell of a lot cheaper!

[Ethel]

A servo, of your type, is a very simple device and replacing the master cylinder will lighten your wallet more than it will lighten the car. It would be worthwhile comparing the bores sizes of the various calipers and master cylinders you have or are considering.

Funny how, when minis didn't have servos as standard everyone wanted to fit one and now they do it seems nobody wants them.

[nmt_oli]

A servo, of your type, is a very simple device and replacing the master cylinder will lighten your wallet more than it will lighten the car. It would be worthwhile comparing the bores sizes of the various calipers and master cylinders you have or are considering.

Funny how, when minis didn't have servos as standard everyone wanted to fit one and now they do it seems nobody wants them.

The servo may be simple, but that doesn't mean i nessesarily want to keep it! I am unsure of its, and my current master cylinders condition, and after spending over £700 of the rest of the braking system (automec copper lines, goodridge braided hoses, KAD 4 pot set up, mini fins, mintex pads all round- you get the idea) i do not want to skimp on the one thing that will make the system work, even if it does cost money. Brakes and tyres are one area where i will happily spend what i need to.

Also, a servo repair kit is MORE EXPENSIVE than a single line master cylinder.

I am asking a question, if I WANT to remove the servo, whats the best way to go about it, and what do i need.

[Turbo Nick]

i did it on my old J reg turbo, you'll need to change the brake pedal or the pedal box whichever you find easier. you'll also need to open up the hole through the bulkhead and the plate under the masters as the older cylinders are a bit bigger.

i ran a dual circuit (yellow master) on my old car and my new ones a 73 so its got the single line setup and i haven't found any problems with it at all.

[[email protected]]

Best to make it as simple as possible. Single line master cylinder, t piece in the bulkhead to split lines front to back. An adjustable/non adjustable brake bias to the rear system, as per the early cars. Everything is simple, and comparitively cheap to replace compared to the dual circuit stuff. Drop me a line if you want a parts run down for it

[steveobennet]

i might be considering this in the future, it would be great if you could put what parts are needed up here for future reference.

[Ethel]

It seems to me that if YOU WANT to ask people questions you have to accept that they are likely to give you their opinions. If you knew all there was to know about the matter in question you wouldn't be asking would you? If someone gave their time to reply to one of my questions I'd be grateful regardless of the answer.

[Dan]

I believe that all cars built after 1976 MUST have a split braking system, you cannot go back to a single line on a road car.

The hole in the bulkhead doesn't need altering, only the hole in the master cylinder baseplate is a different size and it would be better to replace the whole baseplate than to try to alter the one you have, you will never get the hole concentric with the existing one.

The braking valve in your car isn't a bias or proportioning valve. The exact purpose of the FAM7821 valve is a mystery but according to our research appears to act as a delay valve to bring the rear brakes in slowly, this allows them to have full pressure braking but not instantly so the rear won't (in theory) lock up and brake free. They are troublesome when worn but work well when in good condition. If you do decide to ditch it and fit an adjustable proportioning valve then it must not be possible to adjust the brakes from the drivers seat. If you do ditch the master cylinder you currently have and replace it with an earlier type then using a propertioning valve may be the only way to get the line pressures back to what they should be. Hydraulic design of the braking system is very important, which rear cylinders are you using?

[nmt_oli]

It seems to me that if YOU WANT to ask people questions you have to accept that they are likely to give you their opinions. If you knew all there was to know about the matter in question you wouldn't be asking would you? If someone gave their time to reply to one of my questions I'd be grateful regardless of the answer.

Sorry, my post came out harsher than intended. I accept everyone is entitled to thier opinion, but i do not like people forcing opinions. things can be misenterpreted far to easily on the net.

I believe that all cars built after 1976 MUST have a split braking system, you cannot go back to a single line on a road car.

can anyone confirm this, as it makes quite a large difference to the master cyclinder price!


As to which rear cylinders im useing, i cannot remember off the top of my head, but im pretty sure they have large pistons (which can casue problems) but can be easily tamed out with the adjuster valve i have.

[icklemini]

yeah you want a front rear split unless for some reason you think other wise..

brake servos aint really a problem - like others i cant see why you want to remove it, but each to their own...