Morris Minor Owners Club

I have a 66 minor with drums all round. It's been fitted with a servo. As the wife finds it hard to brake. Now when I brake the wheels lock. Do I have to remove the top hat from the master cylinder.

Short answer no. Removing that seal is for disc brake conversions. Drum brakes have powerful springs that retract the shoes, disc brakes have no such springs. The top hat washer helps retain pressure in the braking system which would cause disc brakes to stay engaged and bind.

Drum brakes all round are never going to feel like the brakes in a modern car but they should be able to very effectively stop the car. If that is not the case, the braking system requires investigation

Stephen

The clue is that when you brake, you lock the wheels; but when your good lady brakes, she uses less pressure on the pedal and relies on the servo assistance. It is possible to lock the wheels on a minor without a servo if the road surface is suitable and you press hard enough on the pedal. As above, do not modify the master cylinder, but try less pressure on the pedal.

You could fit a tap in the vacuum line to the servo and have on for your wife and off for you

I may have discribed the problem a little confusing. Regardless of who's driving with the servo connected the brakes are quite violent when pressed. I thought the servo would just ease the peddle, a bit more like a modern car. So there's no way of making them assisted.
would I be better removing the servo.

Rob D wrote: ↑Mon Feb 19, 2024 5:36 pm I may have discribed the problem a little confusing. Regardless of who's driving with the servo connected the brakes are quite violent when pressed. I thought the servo would just ease the peddle, a bit more like a modern car. So there's no way of making them assisted.
would I be better removing the servo.

The Servo just assists the brake operation, it shouldn't make the brakes 'violent'.
I don't think I've ever had a drums all around car that I would describe like that.
My problem is driving the Minor and then getting back in my Discs all around car, that's when the braking is 'violent'...

Was the braking system in good order before fitting the servo? You are correct that the servo should simply reduce the effort needed to press the pedal, it should not make the brakes grab.

The state of the drums, shoes and cylinders can all affect the feel of the brakes. It might be that the servo has an incorrect advantage - there are different versions that give a different gain, you might need a "softer" one.

There used to be brake pads for the Minor (and other classics) that were shown to work as well as disc brakes at stopping an old car quickly, just wondered if it could be the pads not the servo that's making it stop violently.

Rob D wrote: ↑Mon Feb 19, 2024 5:36 pm I may have discribed the problem a little confusing. Regardless of who's driving with the servo connected the brakes are quite violent when pressed. I thought the servo would just ease the peddle, a bit more like a modern car. So there's no way of making them assisted.
would I be better removing the servo.

So disconnect the vacuum pipe to the servo and plug it so air not drawn into the engine and try the brakes, if fixed the servo is too powerful of an assistance, if still the same then its a problem in the foundation brakes.
By violent do you mean the brakes are grabbing and not progressive?

Thank you Bill. I'll try that. It was fine before the servo was fitted. Thought the servo would have made it litter for the wife too use.

There are a couple of different ratio servos around, usually 1.7 and 1.9. It could be that the servo you have is too powerful for the weight of the car.

If the brake shoes are on the wrong way round can that not make the snatchy ? I'm sure I heard that , probably from dad !

panky wrote: ↑Sat Feb 24, 2024 11:26 pm There are a couple of different ratio servos around, usually 1.7 and 1.9. It could be that the servo you have is too powerful for the weight of the car.

I think you'll find the range is a lot wider than that ...


John ;-)

Panky's right...

... and if you have a 4.5 : 1 , your nose will be through the screen.

John ;-)