Brake shoes - a general question | Technical matters | Back Room Forum

Thu 15 May 2008 22:03

Brake shoes - a general question - Chris M

This is a general question about terminology. What is a leading shoe and a trailing shoe?

My theory, and I may be well off the mark, is that the leading shoe is where the piston pushes on the leading edge of the shoe and the trailing shoe is pushed on it's trailing edge. Correct?

Does it then follow that in days of old when drum brakes were fitted to the fronts and had twin cylinders, that both shoes were leading?

Edited by Dynamic Dave on 16/05/2008 at 01:38

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Thu 15 May 2008 22:18

98 1.2 Brake shoes - a general question - John S

You are right. A leading shoe is where the leading edge of the shoe is pushed up. This gives a 'self servo' action as the frictional load tends to push the shoe towards the drum. A twin leading shoe brake therefore needs two brake slave cylinders. Rear brakes are usually one leading/one trailing, so giving reasonable brakes in reverse. This arrangement needs only one slave cylinder.

This one leading/one trailing shoe arrangement was also used at the front on some cars. IIRC early Minis had this, changing to twin leading shoe around 1964.

JS

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Fri 16 May 2008 10:22

98 1.2 Brake shoes - a general question - Peter.N.

I can only concur with John's excellent discription.

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Fri 16 May 2008 13:39

98 1.2 Brake shoes - a general question - Glaikit Wee Scunner {P}

And some people had the nerve to complain the brakes did not work very well in reverse!
I'd a '63 mini and a '74 one. Did not recall that the brake design changed. Old age probably.
What I do remember is a slave cylinder rubber seal popping unexpectedly in both cars.
Ah, the good old days.....

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Fri 16 May 2008 23:22

98 1.2 Brake shoes - a general question - Chris M

Thanks John S for the explaination.

Edited by Chris M on 16/05/2008 at 23:23

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