Morris Minor Owners Club

I found in my collection of spares, a nice new one bought in 1994, which has a spring, cap and piston as shown in the picture.

On the old cylinder, I have the cylinder, a piston with a machined groove (with a rather worn rubber seal ) and on O ring.
Is this an "original". Is there anything else that should be there ? There was a build up of rubber debris in the bottom of the cylinder !

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In my spares I have some small rubber caps,(pictured) which I recall are for the cylinders, or are they just in the rear cylinders ?
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Is it worth buying a cylinder repair kit and replacing the rubber and O ring, or while I am at it, put new ones on as they aren't that expensive ?

One last thing, any specific grease that should be used on the piston ?

The top cylinder you show is an 'original' - the lower one is not. The upper one is MUCH better. Assemble with a spot of red rubber grease for longevity...

Thanks. On inspection of the cylinders, all 4 were rusted and scored so I bought 3 new ones to go with the one I have.
I have put one of those wee rubber caps in the original, between the white cap and the piston, I think that's right, we'll see in a few days when I put everything back together !

The wee rubber caps ARE the seals. None of mine have that little spring you show with the top one ??

Yes Roy, should be fitted, they fit neatly into the groove in the rubber seal

Not in any of mine....

Like Roy, I would have said that there were no springs in the brake cylinders, but according to the BMC Parts List and Workshop Manual there are! My only excuse is that the last time our Minor had front drum brakes was in 1992!

In the Manual there is a reference to 'later cars' (the same reference for the front cylinders is in the first paragraph on the next page of the Manual), and they had the filler cup and spring fitted to both front and rear brake cylinders, so I wonder if the 'early' design looked like the lower cylinder in the picture - I have vague recollections that the rear design was that? I have not dismantled a rear cylinder for some time.

I don't like the idea of a 'loose' piston cup without the filler cup and spring, as there is nothing to hold it in place. The original design has a residual pressure valve in the master cylinder, but that will not remain in the system for very long when the car is not being used. Surely the 'cup seal' design also had the spring and filler cup to hold it in place?
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The words in the Manual suggest that maybe it does not?