02-04-2021, 02:13 PM
The problem with the Morris Minor slave cylinders is that the in and out port for the fluid are the same, and at the front, on each side, a slave cylinder has the port at the bottom, so air is trapped above and very hard to dislodge fully.
It is the same at the rear, but the slave cylinders can also be fitted upside down so the port is again at the bottom, the hand brake lever should be pointing downwards so the port is at the top, if it is mounted upside down, it will be a pig to bleed!
Bleed nipples should be at the highest point to make it as easy as possible to evacuate the air.
Even with the Gunsons Ezibleed, bleeding the brakes is a pain.
I take off the front back plates and lay these on their side (can be balanced quite well above the stub axle) and bleed them that way, it helps get the air out. I also bleed with the drums off, press the pedal down so that the shoes are expanded, there is a limit to how far they will go, so shouldn't pop out the cylinders, then open the bleed nipple, that little extra push from the brake return springs helps to get the last bit of air out.
I have not tried it myself, but will consider it next time, is to remove the upward facing piston (the one that causes the problem), actually fill the bore with fluid and then re-fit piston, the theory is that the piston is fully primed and would make the bleeding operation much easier.
Morris Minor cars have the same problems...
You should also check that the arrangement of the front back plates are so that you have twin leading shoes, NOT twin trailing shoes, they can be fitted the wrong way around. With a standard factory stub axle, fitting the back plates correctly orientated will most likely mean that only 3 out of the 4 connections can be made, as the steering track control arms are in the way, the 4th being blanked off and the uppermost on that slave cylinder being due purpose to compensate for the loss. Twin leading shoes take advantage of the "self-servo" effect when driving forwards (obviously twin trailing shoes when reversing).
Patience is needed with the bleeding operation, once done, you will be rewarded with very effective brake operation.
It is the same at the rear, but the slave cylinders can also be fitted upside down so the port is again at the bottom, the hand brake lever should be pointing downwards so the port is at the top, if it is mounted upside down, it will be a pig to bleed!
Bleed nipples should be at the highest point to make it as easy as possible to evacuate the air.
Even with the Gunsons Ezibleed, bleeding the brakes is a pain.
I take off the front back plates and lay these on their side (can be balanced quite well above the stub axle) and bleed them that way, it helps get the air out. I also bleed with the drums off, press the pedal down so that the shoes are expanded, there is a limit to how far they will go, so shouldn't pop out the cylinders, then open the bleed nipple, that little extra push from the brake return springs helps to get the last bit of air out.
I have not tried it myself, but will consider it next time, is to remove the upward facing piston (the one that causes the problem), actually fill the bore with fluid and then re-fit piston, the theory is that the piston is fully primed and would make the bleeding operation much easier.
Morris Minor cars have the same problems...
You should also check that the arrangement of the front back plates are so that you have twin leading shoes, NOT twin trailing shoes, they can be fitted the wrong way around. With a standard factory stub axle, fitting the back plates correctly orientated will most likely mean that only 3 out of the 4 connections can be made, as the steering track control arms are in the way, the 4th being blanked off and the uppermost on that slave cylinder being due purpose to compensate for the loss. Twin leading shoes take advantage of the "self-servo" effect when driving forwards (obviously twin trailing shoes when reversing).
Patience is needed with the bleeding operation, once done, you will be rewarded with very effective brake operation.
