master cylinder size.

[frogeyeman]

Have got Bond Equipe two litre of 1968 vintage. I have noticed that the master cylinder for the brakes is the same size as the clutch one. Surely the brake one should be larger or is the bore size the same for both but the brake one just has a larger reservoir for the fluid. Hope you can help.

[JohnD]

Bore size, frogeye, bore size!

 

The reservoir size is irrelevant to the action of either system.

John

[frogeyeman]

Thanks John. I know that it is the bore size that matters but is the brake cylinder bore size the same as the clutch bore size? The manual does not state the sizes. Maybe  somebody just fitted what they could get hold of at the time. On the earlier 1600 Vitesse the pictures show both cylinders being of the same size and on the later Vitesse the brake cylinder is larger than the clutch. The brakes are OK  but would like to fit correct cylinder. Car is fitted with remote servo.

[KevinR]

Cars wih disc brakes should use a master cylinder with a large fluid resevoir.

 

When the Herald first came out it had drum brakes all round, and the brake master cylinder had the same sized fluid resevoir as the clutch.

When they upgraded to disc brakes they added a height extension to the resevoir to give the extra capacity.

Eventually this translated into the larger diameter resevoir common on most/all other models.

 

Master cylinders with large (or small) fluid resevoiirs are available with different bore diameters - Externally they look identical,

It's impossible to tell the diameter of the cylinder bore without a full strip down of the cylinder.

[JohnD]

Thanks John. I know that it is the bore size that matters but is the brake cylinder bore size the same as the clutch bore size? The manual does not state the sizes. Maybe  somebody just fitted what they could get hold of at the time. On the earlier 1600 Vitesse the pictures show both cylinders being of the same size and on the later Vitesse the brake cylinder is larger than the clutch. The brakes are OK  but would like to fit correct cylinder. Car is fitted with remote servo.

 

I have no idea, frogeye.    Once removed, it's an easy measurement with a vernier guage.

John

[frogeyeman]

Thanks for replies, I will get hold of later cylinder when at the Beaulieu autojumble.

[Pete Lewis]

I believe the early   drum /type 12 and 14 calipers were  0.625 the mCly dia changed  from 0,625 to 0,7" with intro of type 16 calipers  as greater volume required due to piston displacement , 

 

fit a  0.7 to a 0.625  spec  and you will raise the pedal pressure for the same braking.   

 

pete