Perhaps returning to basic thinking could be of some value...? GoMoG information is the result of years of the experience of many hands on Morganeers and professionals of all types, added to very many miles travelled in different countries if not continents by the webmaster there, thus would seem to be quite the best source of information available with no charges attached, of course there may be those who think differently.
Basic thinking.... If the brakes are sticking on in ANY way, then that will show up as heat on the disc or drum after a very short journey of a few hundred meters/yards where the brakes have been applied BEFORE starting the run, this will show up as the affected drum/disc as being HOT to the tough, perhaps hot enough to burn skin... take care..!!
If heat is felt, this should be looked into, in a worst case scenario the heat can build up and feed into the brake fluid which can boil to the extent that on the next occasion brakes are required the brake pedal may have little effect in terms of applying the brakes..!!
The pics of the rear drum brake system show a double acting cylinder.... it has one force applied by the brake fluid that operates two pistons directly acting as the result of that one force... the designed of the brake system using this type of cylinder/piston arrangement depends upon both pistons being free to move equally relative to the applied pressure..... With the possibility of corrosion build up more on one piston more than the other the BALANCE of the operation is lost to the extent that one brake shoe can wear more than the other.
This imbalance may not be detected easily and may not be found until the drum is removed during maintenance.
IF one shoe seems more worn my first check might be to have a look at the rubber outer boot on the end of the cylinder that operates against the less worn shoe.. if there is any fluid found then it could have caused either the piston to corrode, or may be a sign of a leaking piston seal.. I have found both corrosion and leaking seals though the latter in an advanced state usually shows up with damp back plates, and if allowed to continue will eventually contaminate the drums and shoes with brake fluid..
On the other hand if one of the pistons has corroded it may take much more brake pedal pressure to force it to move, and logically(?) if it is harder than normal to get it to move out, it will be harder for the brake springs to make it retract, thus the shoe may stay in contact with the drum in varying degrees from a light rub to something generating ever more heat..... The latter can be discovered after HEAVY braking where the extra force applied caused a sticking piston to move out of position and stay out..
My usual quick test is to employ a long screwdriver, engaging it`s tip in the flange of the brake backplate, approximately in line with the centre of the arc of the brake shoe and using the screwdriver as a lever, I lever the shoe in the opposite direction to that of it`s normal travel when the brakes are applied, observing the pressure applied and the amount of movement of the piston attached to that shoe.... it should be seen to move reasonably easily.
I do the same on the other shoe which if all is well not only move similarly but also cause the other piston to act on the other shoe.... in which case... all seems well, other than now the shoes will not be centralised with the drum, and require a bit of fiddling to get the drum back on... after the brakes have been operated the shoes should then be centralised once more..?
If a sticking piston is not discovered when looking for the cause of an overheating brake drum or excessive wear on one brake shoe compared to the other, then the cause could be handbrake related, as any stifness in it`s operation could hold the rear brakes ON partially in varying degrees...?
The handbrake mechanism if not adjusted correctly and free in all aspects of it`s operation can cause all sorts of issues.... but then it seems possible the GoMoG article may have addressed that..?
Try to stick to basics when fault finding that way you may gain a better understanding of the way things are supposed to operate..?
My thinking could be well out of date on any subject thus perhaps best to treat it with a degree of scepticism.. Happy to discuss further if thought to be of any advantage..?
