12 replies to this topic

[JonnyAlpha]

Hi;

 

As part of an Engine upgrade I will need to convert from Drums to Discs and have done loads of research.

 

The car is a 1982 HLE 1000 and I noticed that there is brake or clutch fluid always lying around the base of the master cylinders. After having to dry the car out following pretty bad wet weather driving back from Castle Combe, I noticed that it looks like brake or clutch fluid has been leaking down the inside of the bulkhead inside the car.

 

For the upgrade I thought I would need to add a new Brake and Clutch Master Cylinder (A cost I had not anticipated) but also noticed that Mini Spares also do some refurb / repair kits.

 

When looking just now at poss replacement Master Cylinder I saw this one and  saw it mentioned fitting it as an upgrade when converting to calipers.

 

So my questions are as follows:

 

1. When I dismantle the Brake and Master Cylinders to re-vamp the Engine Bay, might I be able to "tighten" anything up to remove the leak?

 

2. Is it worth repairing using a repair kit?

 

3. When converting from Drums to Disc Brakes, do you need a larger Master Cylinder?

 

Many thanks    

 

[ADRay]

I am by no means an expert, but when I upgraded the brakes on my ‘82 1000 HL, it didn’t require a different brake master cylinder. I had coincidentally replaced the old one a month or so prior though.

[absx2]

Just my personal opinion having done a few brake swaps. 

Firstly you will have a split circuit master cylinder on a 1982 car so legally ( i think ) you cannot change to a single circuit system, either way your insurance company would take a dim view of it.

The existing cylinder works fine on a 8.4" disc set up and it was actually used on the unassisted ( non servo ) cars on a C reg onward so no worry's there.

With the 7.5" disc`s personally I feel they lack a bit of bite so you may wish to add a servo in which case I would source a 1988 onward servo and buy a new dual circuit master cylinder for it. You may be happy with them so try it first.

 

Repairing master cylinders with seal kits is a false economy and I 100% guarantee the bores are pitted so apply your time to something more fruitful.

Yes there are loads of people who say it worked fine, but for how long ?

 

In your instance you may want to just check the caps are OK and you haven`t overfilled as they are vented.

[Ethel]

Repair kits are ok, but if it's the original cylinder it's knocking on for 40 years old. If you haven't got time to strip it down and inspect it thoroughly before ordering parts I can't see much of a risk unnecessary expense.

 

I had no trouble locking up wheels with "S" discs & no servo when I ran out of driving talent, even with the old single circuit pedals.

 

The hydraulics give comparable performance but 8.4" discs give the pads a bit better leverage against the tyre footprint than 7.5's. Four pot calipers would be an alternative to a servo if you decided you needed to address that. You could also use a remote servo on the front hydraulic circuit only, as an alternative to thee late model horizontal master & servo combo.

[JonnyAlpha]

OK thanks for the tips.

 

As far as I can tell I currently have this brake setup? Which has a yellow tag Master Cylinder GMC227:

http://www.minispare...|Back to search

 

I have managed to get hold of a spare Front Subframe which I am hoping (cash permitting) to build up read to take the new engine which will save time when doing the swap.

I plan to renew all of the brake lines but a having trouble working out what parts do I need.

 

I think I'll need:

 

Left to Right connecting brake line:

http://www.minispare...ck to catalogue

 

Left and Right Braided Hoses:

http://www.minispare...px|Back to shop

 

I need to do some more research to identify which connecting unions I need.

 

 

Depending on the condition of the original, I may also need these:

http://www.minispare...px|Back to shop

 

 

I will also be renewing the front to rear brake line:

http://www.minispare...px|Back to shop

Edited by JonnyAlpha, 28 December 2019 - 06:39 PM.

[nicklouse]

Just bolt the calipers on.

 

as the system is open you can always get some leakage from the vented cap  after some spirited driving or when the system is over ful.

[Ethel]

You could get  some flaring tools and make your own lines. It'll add some expense, but pays off in the long run if you''re a committed car tinkerer.

 

Min's can leak through the  master cylinder mountings. It's as likely to be water, pour some on the screen 'n open the bonnet to see how the bonnet gutter drains. If you park nose uphill it wouldn't take much to make a puddle on top of the bulkhead cross-member. It'd be worth replacing the gaskets, or just squirting in some sealant if there's any doubt. If the Master itself is  leaking it'd most likely run down the push rod on to the clevis pin.

[nicklouse]

Hi;

 

As part of an Engine upgrade I will need to convert from Drums to Discs and have done loads of research.

 

 

 

When looking just now at poss replacement Master Cylinder I saw this one and  saw it mentioned fitting it as an upgrade when converting to calipers.

 

 

This is only recommended when changing from single line drum to single line discs as the reservoir is larger to compensate for the extra fluid needed as the pads wear unlike the when the shoes wear. It is basically S spec. What you have now is a better set up.

[Homersimpson]

Repair kits are ok, but if it's the original cylinder it's knocking on for 40 years old. If you haven't got time to strip it down and inspect it thoroughly before ordering parts I can't see much of a risk unnecessary expense.

 

I had no trouble locking up wheels with "S" discs & no servo when I ran out of driving talent, even with the old single circuit pedals.

 

The hydraulics give comparable performance but 8.4" discs give the pads a bit better leverage against the tyre footprint than 7.5's. Four pot calipers would be an alternative to a servo if you decided you needed to address that. You could also use a remote servo on the front hydraulic circuit only, as an alternative to thee late model horizontal master & servo combo.

Personally I would be wary of servoing the front only, I have a kit car where the front brake discs were new but quite rusty and to get it through the MOT i plumbed a servo into the front and it was almost undrivable.  The front wheels locked at the slightest thing and the rears were doing very little.

[Ethel]

Innocenti Minis were built like that: dual circuit, remote servo.

[Homersimpson]

Innocenti Minis were built like that: dual circuit, remote servo.

 

If they were designed like that do they have different rear cylinders to compensate?

[no66]

 

Repair kits are ok, but if it's the original cylinder it's knocking on for 40 years old. If you haven't got time to strip it down and inspect it thoroughly before ordering parts I can't see much of a risk unnecessary expense.

 

I had no trouble locking up wheels with "S" discs & no servo when I ran out of driving talent, even with the old single circuit pedals.

 

The hydraulics give comparable performance but 8.4" discs give the pads a bit better leverage against the tyre footprint than 7.5's. Four pot calipers would be an alternative to a servo if you decided you needed to address that. You could also use a remote servo on the front hydraulic circuit only, as an alternative to thee late model horizontal master & servo combo.

Personally I would be wary of servoing the front only, I have a kit car where the front brake discs were new but quite rusty and to get it through the MOT i plumbed a servo into the front and it was almost undrivable.  The front wheels locked at the slightest thing and the rears were doing very little.

 

I ran a servo on the fronts with really good pads (MS carbon metallic)  and was perfecly drivable. Could lock them up if I wanted, but tonnes of feel and so good braking. Dual master split front / rear with inertia rear limiter. 72 model. 



 

Edited by no66, 30 December 2019 - 07:37 PM.

[Ethel]

 

Innocenti Minis were built like that: dual circuit, remote servo.

 

If they were designed like that do they have different rear cylinders to compensate?

 

Couldn't tell you, but don't see any reason for them to be different - the servo would relatively increase the braking at the front, but that wouldalso mean relatively lower line pressure to the rear and a pressure limiter would still isolate the rear at the same pressure.

The servo also provides a proportionally constant pressure difference as you need to maintain the hydraulic pressure behind the piston to keep the air valve from closing - it performs much like smaller wheel cylinders would.