Hydraulic Brakes

[Henry Harris]

Last night I was given a rather battered Super Accessories 'Austin Builders Guide and Price List''

This was tucked in the back cover.....

   

[Nick Lettington]

That's brilliant Henry... do we know what the special blanking plate and adaptor looks like?

[Dennis Nicholas]

That was originated by the father who had Bowden Engineering.  His son who continued the firm has now retired and the firm closed down with all equipment sold off.  See the A7CA archives for the drawings of the Independent Front Suspension Bowden used to do.....I had it fitted to my everyday Nippy back in the 60s.....transformed the handling.....even at speed (75+ mph).......sorry to purists but those were the days of specials and every day 7s as runabouts.

It is well worth reading up various words of wisdom about which way round to fit the cylinders etc.  In this way round (two leading shoes) the cylinders push the leading edge of the shoes out against the drum and as soon as the shoe touches the drum so the braking force is increased even more.  It is important to get the shoes the right way round as well.....the Morris Minor book shows correct way.
At the rear with the leavers pointing upwards the piston pushes leading edge of top shoe to drum and is leading shoe but the cylinder slides down in its slot in the back plate and pushes the trailing edge of the bottom shoe against the drum which produces less braking force so at rear it is one leading and one trailing thus the rear braking is less effective which is what you require front to back.
To ensure leavers point up remember that it may be necessary to swap the back plates from one side to the other so cylinders in the plates allow upward pointing leaver without leaver touching anything.  I am not sure that the leavers need to be pointing upwards......they just do on the MM.

Handbrake cables.....best not to use Morris Minor because each one fits to each side of a single rod that goes through the base of the hand brake leaver so there is no compensation and each cable is adjusted at the rod for amount of pull on the cylinder.....back to it being a pain to keep a balanced pull at back!  I used a handbrake leaver that had a single rod pivoting off the hand brake pointing backwards and terminating in a fork end.  Into this fork end is inserted a cross bar that is free to swivel about it's middle and the end of each cable goes into each end of the bar.  This gives the compensating action where the fork pulls on the centre of the swivelling cross bar and as the shoes of each side contact their drums and perhaps give a different force on the cable so the cross bar swivels until the force on each cable equalises.  Unequal wear of shoes side to side is thus automatically compensated for.  I just happened to use Allegro  1973 to 1982 cables with their swivel cross bar.

Of interest are the different adjusting "snails".  Smaller from front because there are two, larger at rear where only one to take up wear of two shoes and even larger for the later 8 inch brakes with even more adjustment take up.  It is still a mystery to me why I run out of adjustment long before the shoes are worn down to anywhere near minimum thickness......this has been on more than one set of hydraulics and with new drums.  To compensate I have had to fit packing strips between shoe ends and pivot points......even with the largest snail at rear and the rear snails at the front........baffeled!

   

   

[Charles P]

I used an early handbrake mounted “back to front” so that you push to put it on. Morris Minor van handbrake cables work well with a short balance bar.

Charles