10 replies to this topic

[Jordie]

Hey everyone

If you have been reading my projects page, you will know i have fitted discs to my 1980 mini. I always thought it had 'single' brakes. But after discovering a wet patch, tracing back to this:



I am not sure. I have no idea what the black thing is called. I have had problems with my brakes for awhile now, so i want to know if this leaking could be the cause.

If it is split line brake setup, can i replace this with one from a 1986 mini (with discs)?

Also, if using split line brake setup, can i use the rear brake cylinders from the 1986 rear brakes, as one of mine is leaking (and i need to change studs for longer ones etc anyway)

Just to make clear, MY mini is a 1980 Mini City (originally fitted with drums allround)

Thanks guys.

[Boab]

That is the brake slave cylinder. These are relatively cheap. I paid around £10 for mine. The big round one on the left is a Lockheed master cylinder for a single circuit system, which yours look to be. Tandem ones have a larger brake servo and has a different setup to yours.

[Jordie]

Havent got a pic, thats the best one i can find. The clutch master cylinder is to the right and the brakes on the left. Its taller and has a resivoir at the back (clearish/white plastic).

Any help appricated.

[Pavel]

Help has been given dude Read above!

As for wheel cylinders, they should work (since you got discs from that car isn't it), but do not swap only one, swap both at the same time. to be honest I'd just get a pair of brand new ones. For the sake of 15 quid you'll know they won't leak for a while!

Be aware, the circlips are IMPOSSIBLE to put on!

[siggy]

This is a dual circuit braking system.

First there is NO such part as the brake slave cylinder.

Only the later (post 90ish) have servos.

Jordie which part do you mean? the Brake master cylinder is the top left, clutch master cylinder top right and the cylinder at the bottom left is the brake compensating valve.

The valve on the 86 car will be the same.


Siggy

[Madmax]

dual line master cylinder a pretty penny to buy recon'd or new

100 quid upwards

[Jordie]

"bottom left is the brake compensating valve"

thats the one.

[Dan]

Your brake master is the dual line one with the built in PDWA (that's what the electrical connection is for). This means it has imperial fittings and if you ever want to change it you will need also to change the short lines that run from the compensating valve to the MC as you will need new metric fitting versions for any new master (there are no new or recon imperial threaded MC's available). You will also need to do a little wiring to the brake failure warning circuit. This is all covered in Haynes and the official book as it is a Rover upgrade/repair procedure.

The thing on the bulkhead is indeed the compensator. It is called the FAM7821. It was fitted to a fair few Rover cars and was rubbish on all of them. It breaks really easily and can't be fixed. It is very likely that this is causing your brake issues as they are famous for it. You might be lucky and find a second hand one which works but I never have. New ones sadly are about seventy notes. Some people say it isn't important and you can ditch it but I think they are important on a road car (Think about it, would Rover have fitted it if they didn't need to?). I think it works as a delay valve to delay the rear brakes by a few tenths of a second, no one is entirely sure. But basically what it definitely does is stop your rear brakes locking up before the front ones are working, which would cause you to spin.

You should fit the correct rear cylinders to work with your new front discs or your pressure distribution will be all wrong. If they are the ones from the '86 car then that's what you should use.

[Jordie]

I have the complete setup from a 1986 mini,but the disks are NOT from the same mini.

I dont think this will cause any problems, i have a 1986 mini for breaking at my friends, i will take the valve and see what its like.

thanks

[Boab]

That is the brake slave cylinder.

My mistake. I meant to say 'clutch' but I'm a bit dyslexic when reading and putting the same word down on paper.

And technically, the metal bit in the middle of the first picture is actually called a 'pressure reducing valve'.

[Jordie]

the valve thing. anyway i took one from the car me and a friend are breaking. Havent fitted it yet tho.