[Healeys] Fwd: bugeye brake problem

mark henderson markhenderson3376 at gmail.com
Thu Oct 31 11:52:46 MDT 2013


I have a rear brake issue with my '58 Sprite.   The Bugeye has the stock
.875" rear wheel cylinders and we have installed a 1967 Sprite/Midget
tandem master brake cylinder and front disc brakes. The problem is; we can
turn the rear brake drums by hand when the front brakes lock up. We have
sealed all leaks and bled the system thoroughly, no air remains in system.
We have adjusted rear brakes shoes as tight as possible. We backed off
pedal stop to try to increase piston travel in master cylinder. When we
bleed front brakes first then check rear brakes, drums are locked.

My summation is that the new master cylinder is not pushing enough fluid to
the rear brakes before the fronts lock up. When the front brakes lock, the
piston cannot go any further into the cylinder to push any more fluid to
the rear brakes. Bleeding the fronts first and then checking the rears are
locked seems to prove this. I have gone thru the math to see if the
original .875" cylinders require a lot more fluid than the .75" cylinders
of the 1967 Midget and they will require more volume of fluid to travel
equal distances but not a lot.

Short of replacing the rear brakes with later Midget/Sprite  backing plates
and wheel cylinders, does anyone know of another fix for this? Has anyone
done this swap before with only the tandem master cylinder and front disc
brakes swapped over. My old Lucas/Girling books show no wheel cylinder with
smaller bore that will fit the Bugeye backing plates. Thank you for any
thoughts.  Regards,  Mark


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