I've been trying out my Rossa brakes on my drive and they're completely hopeless - the pads feel as if they're made of wood I have Metro vented 4 pots on the front with slightly worn pads and discs that have had hardly any use and have just had surface rust removed. The rear has Mini back brakes with Minifins and slightly worn shoes and there is no servo. The dual line master cylinder is new and is from a Metro with a servo - I have used this one because it has plenty of clearance below the bonnet. Pedal feel is fine. The pads and shoes need proper bedding in but there should be at least some stopping power whereas there's practically none. I have plumbed the master cylinder so that the upper line goes to both front and rear brakes and the lower line goes to the front only - I suspect that that this might be the wrong way round. Can somebody please confirm what it should be? If I have it wrong, given that the seal diameters and piston travel for both lines is (presumably) the same does it make any difference anyway? It would be great to hear that even if it's wrong it doesn't matter because I've had all sorts of problems with brake calipers and really don't want to disturb them again now that I have them fluid tight (for the record I have had 2 reconditioned calipers on the nearside and 4 on the offside - one has leaked at the piston seals and the others have all leaked at the bleed nipples Reconditioning has obviously not been very well carried out...)

While I'm at it, I've just bought a non vented 8.4" 2 pot disc setup from the front of a Mini that I intend to fit to the rear sometime using a handbrake conversion kit from Rossabitz - will this make a vast improvement to the handbrake? I'm just forming a contingency plan in case my current handbrake doesn't measure up...

As usual, all contributions gratefully received

I would expect the handbrake to be worse on the rear disk, the disk would be used (necessarily) to improve dynamic braking.
Worth checking but I suspect the bores of the servo master cylinder would not be suitable when used without one?

Anyway, compared to modern cars the brakes will feel useless on the rossa and coupe you need to press hard and wait.

I'd suggest that using a master with bore sizes designed for servo assistance is likely to be the problem and that it's never going to feel good. Take your modern car somewhere safe and try the brakes with the engine switched off so the servo assist isn't there. At anything over walking pace it's scary. First time I experienced it in an 80's car I was really frightened by how bad the brakes were without the engine assistance.

Also - didn't the Metro use an inline pressure limiter to the rears? Have you got that?

My Coupe's brakes were A1 with the Mini single circuit master and Metro 4-pots on the front and MGF calipers on a Mini standard disc on the rear. A good shove of the pedal wold lock the fronts and a REALLY good shove would lock all four - no bias or pressure limiting device involved. Handbrake was the Mini handle with modified Minor cables onto the MGF caliper and again it could lock the rears on the move. I've changed to an OBP bias box as part of the re-build and I really hope I can get it back to the same balance as the single circuit master.

Iain

Many thanks for your replies. I decided on the master cylinder I used (which is 20.6mm bore) after reading the GTM Technical Manual where it is mentioned as being recommended by GTM although it doesn't exactly say whether it should be from a servoed car or not. However, the writer used the one from a servoed car because it was the only that fitted under the bonnet. Apparently it worked fine although a good shove was needed on occasion. I don't suppose that GTM would recommend a cylinder that needed bits hacked out of the bonnet which the non servoed one would need. I haven't fitted the Metro inline pressure limiter. I wouldn't be averse to fitting a Mini remote servo but I was advised against this originally because it makes it too easy to lock up the front brakes.

I would still like to know if I have plumbed the master cylinder the wrong way or if it makes no difference. Has anybody gone down this road?

I know exactly what Iain means about modern car brakes - I just have to look at the brake pedal on my Mazda 3 and the car stands on its nose but without engine assistance it's very scary indeed We get so used to this that we forget what it used to be like in the good old days when Mini was king (showing my age now )

Thing is my GTM did feel like a modern car but without the complications of a servo and you know that it'll be exactly the same whether the engine is running or sat on a pallet three miles away. I really hope I can get the same performance/balance/feel back with the new setup.

I had this discssion with the MOT tester last time - I was sat in it doing the basic controls (lights, wipers etc.) as he couldn't climb in and out so easily so I drove it onto the brake rollers, switched off the engine and got out for him to take over the controls. He said the test was to be done with the engine running and I pointed out that it wouldn't make a difference but he clearly didn't understand why and just followed what the book said. He also failed it until I pointed out that where the rollers thought the front wheels were still turning they were actually locked - so he did it again with the front clam open so that he could actually see the wheels instead of just relying on the silly machine and it passed with flying colours.

Same lad also got a telling off when I spotted him testing my 4x4 Sierra on the brake rollers

You would think that the MOT tester had come across a car without a brake servo before, wouldn't you?

I once left my Subaru to be MOT'd and when I went back for it I found it being brake tested on the road (as it should be) but at nearly 3 figure speeds (which it shouldn't be)..........apparently the deceleratormometer thingy test is supposed to take place at below 30 mph

Anyhoo, anybody got any comments on my plumbing? (master cylinder, I mean...)

Raymond, it's a tapley meter

Not sure on your plumbing but a lot of the dual circuit systems were 2 fronts and 1 rear on each circuit.

Looking at my K3 which runs a Metro tandem master cylinder and also my MGF which also has a tandem master cylinder the outlet nearest the servo supplies the front brakes only and the outlet at the top of the master cylinder supplies the rear brakes through brake pressure limiter valve.

I knew that...........

I've plumbed it as per the book (Haynes) with one circuit doing back and front and the other doing front only but I'm just not sure whether I've use the correct circuits. PEEPS' setup sounds different again but he has a servo. I thought this bit would be straightforward

Something I noticed when sitting in the car today and pressing the brake pedal is what a small pedal it is compared with modern ones. It's probably psychological but it might help to fix a bigger plate to it then I could give it a good thump!

Ay up i've had a few but I'll try and explain.

You are shoving a shaft down the cylinder with 2 plungers on it with a bulkhead in between.

Both move the same distance at the same diameter, but, the one nearer the pedal has less fluid and capacity due to the volume of the shaft it sits on.

This explains:http://www.tegger.com/hondafaq/mastercylinderreplace/howworks.html

So, the one nearest the pedal goes to rear, the other to front.

A few what

Thanks for the link - it's a very good article, that, and it got me thinking again What you're saying is that the half of the master cylinder with the greatest fluid capacity operates the brakes with the most fluid capacity which makes sense. The cylinder described is slightly different from my cylinder in that mine has a shaft in both halves. Looking at the diagram in the manual the bottom shaft is around 50% thicker than the top one (which makes sense) but, on the other hand, the bottom one is a good bit longer. There are so many variables in this that it's impossible to give a definite answer to my query however, while searching for the exploded diagram, I came across the bit I was looking for all along (an article from a magazine) and it states that the primary circuit operates the front and rear brakes while the secondary circuit operates the front only, the primary circuit being the one nearest the pedal so I've got mine the wrong way round Booger I'll have to swap the lines around at the cylinder which shouldn't be a problem because the bottom one looks as if it is long enough to persuade it to reach the top but I hate bleeding the damned things. Ah well, I've answered my own question I suppose but thanks all for pointing me in the right direction or I'd never have found that article.