MORRIS MINOR BRAKES. 48-62 or 62-71

[Rpm]

Hi forum members. I have been trying to make my brakes work better on my A7 which is fitted with a Morris Minor conversion. This was fitted long before my ownership and probably in 1960s. I have the choice of 2 options for the front brake shoes. 1948 to 1962  or 1962 to 1971. Would someone be able to suggest which I would need?.
Replaced the front cylinders x 4, bled the system but the brakes still terrible so I'm going to now replace the shoes.
If that doesn't work, I will look at the master cylinder although that appears strong and not leaking. There is only a very small travel on the foot brake, approx 2.1/2" from fully off to full pressure.
Any help with the late or early brake shoe confirmation would be appreciated.
Thanks All. RPM

[Jeff Taylor]

As far as I'm aware the Morris Minor 1962 to 1971 brake drums / shoes were 8" whereas the 1953 to 1962 brake drums / shoes were 7". I believe the brake drums on the Series MM Minor (Morris 8hp side-valve engine) 1948 to 1953 were different again to the later drums, but may have used the same 7" shoes. I'm no expert on Austin 7 hydraulic brake conversions, but many that I've read about in articles or on the forum if dating from the 1950's or early 1960's seemed to use the 1948 to 1953 Series MM Minor hydraulic brake parts. ESM carry a good stock of Minor parts including 7" and 8" shoes.

https://www.morrisminorspares.com/brakes-c42

[Dave Mann]

I wonder if the linings are too hard for a Seven, I had a hydraulic braked Seven in the 1970s with all new cylinders and linings and the brakes were appalling initially not a lot they one front brake would grab and it would go off left or right. The problem was cured by fitting softer linings. I would suggest a chat with Saftec.

[Charles P]

Early, 48-62 shoes and the right snail adjusters, properly adjusted either through a hole in the drum or backplate.
Bleeding can be fun, depending upon where the bleed nipple ends up. Some set ups, such as mine, only leave a space for it in the downward position. I took the backplates off the stubs and bled them before reassembling

A picture from you may help to understand your set up.

c

[Jeff Taylor]

How old are your brake hoses ? These can collapse internally severely restricting fluid flow whist looking perfectly OK and serviceable on the outer surface of the hose. I would certainly consider stripping the master cylinder and replacing all the rubbers with new and at the same time checking the bore for any surface corrosion scoring etc. A rotating stone hone is available for cleaning up the bore - the bore can also be S/S sleeved or failing that, new master cylinders are available.

Note that the early 1948 to 1962 master cylinder had a 7/8" bore whereas the 1962 onwards had a 13/16" bore.

[Rpm]

Thanks, guys. Jeff, Failed to mention new front hoses. Yes, I have the front holes in the disc to adjust snails, 2 cylinders in each wheel. How tight should the brake shoes be against the disc. mine is set to almost touching. Got my wife to sit in the car and hold the brake down and with a bit of effort and the car jscked just off the ground i could turn both wheels using the same strength so once rolling nothing there.
Good brake fluid flow when bleeding. Bleed nipples at the front facing down.

[Charles P]

I did quite a bit of filing high spots on the linings to get a good level of material in touch with the drum on mine. I also chucked away the cheap MM linings and bought some decent brand ones (took a bit of looking). 
As you probably know if the pedal firms up with pumping, it's a bleed problem. However, if you can still turn a wheel whilst your wife is pressing the pedal, the brakes certainly aren't working well enough.
Also with a dropped axle I found that "tie bars" between the top of the axle and the radius arms were essential to avoid jumping leftwards into the verge when the brakes were applied heavily.  
It's been worth the effort because the brakes are now very reassuring, either on the track or in traffic. 

c

[Rpm]

Charles what linings are on your car ? Dave Mann suggested saftec or jeffs ESM. The master cylinder is the later type and the pushrod about 3" long, I feel it should be longer , I will take it out and put new rubbers in and check the bore.
Charles it could be that there is very little overall contact with brake shoes and disc,so filing as you said maybe the answer.

[Charles P]

I bought some Mintex ones. Yes, they're not the same as Mintex of old but were better than the cheapest ones, which get some criticism on the MM forums.

I despised the idea of the MM master cylinder bracketed to the chassis so mounted an MGB master cylinder on the rear cross member and made a pivot block that fits inside the chassis. A bell crank turns the "pull" from the pedal into a "push" on the master cylinder, and by adjusting the pull positions on the crank I can adjust the ratio.
I've subsequently removed the whole brake cross shaft assembly when I put hydraulics on the rear as well, offsetting the extra weight of a 2" square block of steel mounted in the chassis!

   

[Paul N-M]

Hi RPM,
An article I submitted to this forum on 26/8/20 may be of interest if you do a search. Title: Brake, Brake, Brake.

It does deal with my efforts to better my hydraulic brakes for competition which in my view has been very successful. However the basic principles still apply even for a road car.
I would not use Saftek Green Gripper in a hydraulic system. IMHO it is not ideal for the pressures generated and resulted in problems. MM 'Mintex' linings from a good supplier such as ESM should be fine. They should be bedded in though (see my method in the article).

Your are using a single master cylinder so I suggest keeping the bore to that of the original MM system provided your rear slaves are also the same size as the MM system. The front slaves were the same bore for both 7 & 8" MM drums. However make sure you have the 7" masks and snales as they differ from the 8" ones.
I think there were two m/c bores. The smaller one will generate more pressure at the expence of more pedal travel.
Also if your non MM m/c is lower that your slave cylinders you may want to fit 10lb residual pressure valves in line to f & r.

Be carefull about changing ratios of brake pedal and (your) bell cranks as this will effect both force and pedal travel. Personally I dont like a long travel brake pedal but for the road a couple of inches should give some 'feel'.

It goes without saying all components need to be in first class condition. Any doubts and they should be changed for new. All bits are innexpensive. Properly set up hydraulics work very well so work through methodically to sort the issues and you will have excellent brakes.

Good luck.

Paul