Morris Minor Owners Club

hi there

looking to change my rear brakes on my moggy I have a 1275 ital engine gearbox and rear axle with disc front brakes and drums rear. I am wanting to change the rear to disc is there any conversions that have been done already??? I was thinking of maybe doing it with bmw e30 rear discs or vw polo disc! has anyone got any tips or advise????

The rear brakes do not have very much work to do, and under heavy braking with front discs can lock up with the standard Minor 7" - the Marina rears are 8" I think?

We have Metro front discs and have had to insert a pressure limiting valve into the rear brake circuit, to prevent the 7" rear drums from locking up under hard barking (the linings are harder than standard, but can still lock up).

There are disc kits available for the standard Minor rear axle, as the ends are the same as a Midget, but whether anyone has anything available for a Marina I do not know.

Apart from an interesting challenge, why do you want to fit discs to the rear?

I had Marina front discs and a Marina rear axle/drums fitted to my Ser 2 Minor which was fitted with a tuned engine; and the Marina front/rear brake set up was more than adequate for my very non sedate driving and I never had any brake fade or over braking on the rear. It was not fitted with a brake servo which I consider would have caused over braking on the rear.
As above the rear brake do very little when undertaking hard braking as the load transfer is off the rear axle/brakes & tires onto the front brakes/tires. The Minor engine is in front of the front axle/hub pivot point which does not help with the rotational load transfer.
Even on my comp Minor I have only the larger Wolseley brakes on the rear (Marina discs on the front) which are more than adequate and again without a servo.
I am not saying do not do it - but I do question the need for undertaking the conversion as I consider your existing brake set up to be more than adequate even with the 1275cc engine.

I really want to just have something that is completely different from everyone else but looks standard! I think I could do a disc brake rear conversion it just how to mount it on to the rear axel!!

you asked for advice and the advice from people is.. it is not needed and the two respondents know there stuff and is in line with a response from JLH a few years back I recall

if it is going to be completely different... how can any one tell you how to do it or they will have done it and your car will not be completely different (the pedant in me coming out).

Lots of things can be done...but to what purpose? I look at most modern cars and think 'what is the point of that?' Another thing that I'll not use before we sell it! Not much point in discs on the back (or front?) of a minor for normal driving.

I don't want to discourage you because it would be interesting to see what can be done.

From previous poster's answers something like a Midget rear brake kit would be a good start, preferrably with small, non ventilated discs so I'm thinking the Polo or BMW options you were thinking about probably wouldn't be suitable.

Because of weight transfer under braking, roughly 2/3's is done by the front wheels and only 1/3 by the rears. To prevent the rear wheels from locking before the fronts -and causing a loss of control- You need the front brakes to be AT LEAST twice as powerful as the rears. This is very important!

So before the rear discs, do make sure you have nice, big ventilated ones at the front and that the piston area in the calipers is roughly twice that of the rear calipers.

And do post pictures if you do it.

A disc/drum front/rear set up was considered to be adequate for the Rover SD1 3500

I purposely only run Moderns with drum rears.

Everyone has their own preferences, I run my Moggy on just the stock drums which are adequate and work just fine when driving within reason, while my (10 year old) modern has all discs which are frankly fantastic and never fade even with enthusiastic driving down steep mountain roads.

Braking power and fading aside, I've found it easier to change pads and do maintenance on disc brakes than drums so that's another advantage for the discs and I'd love to see a clean, well made conversion. Probably overkill for a stock 1275 but then again it's brakes so it's better to have too much than too little.

For the Minor/Sprite/Midget rear axle there is a well made rear disc brake kit from Peter May Engineering.
http://www.petermayengineering.co.uk/sp ... ts.htm#3.4
But at £469 plus the usual even I could not justify the expenditure.

See also previous discussion re this subject:-

http://www.mmoc.org.uk/viewtopic.php?f=25&t=25754

If you could see the discs through alloys yes it'd look smart (the custom builder in me).
But a 2 ton 300bhp 7ltr V8 Lincoln Continental has drums all round !!

MrIan wrote:If you could see the discs through alloys yes it'd look smart (the custom builder in me).
But a 2 ton 300bhp 7ltr V8 Lincoln Continental has drums all round !!

Precisely, try stopping in one of those.