I finally got tired enough of suffering with these things to post this note. These brake shoes are too small when installed. The linings appear to be correct thickness, but the steel carrier shoe must be too short. When installed with a new brake drum exactly 10.000-inch diameter as original, the snail cam adjusters will run far up the adjustment range with the new shoes. For rear brakes the adjuster will run up 18 notches (to the maximum adjustment), and the shoes will still not touch the drums. Front drum brakes with two adjusters may only run half way up the range on first installation, but will be at maximum adjustment by the time the linings are only half worn.

The hydraulic brakes will be effective with the new shoes, but the parking brake may or may not be fully effective, and you may have long pedal travel to make the brakes work. As the shoes wear the pedal travel gets longer, and the parking brake gets less effective. In short time the parking brake becomes very weak, especially when rolling backwards down a small grade (useless), because the activating lever in the rear slave cylinder hits maximum travel requiring more adjustment of the shoes.

When the rear shoes require first adjustment due to wear, the shoes must be replaced, because they cannot be adjusted farther, even though the linings are only minimally worn. So you have to pay full price for new shoes that will only provide about 30% (at best) of normal service life before they have to be replaced. The dual front adjusters are more forgiving and may work until the linings are about half worn.

If you need to have the brake drums turned as a normal service procedure, the rear brakes would become immediately useless with these undersize shoes, and front drum brakes might be at end of adjustment range with initial installation of new shoes.

I have reported this problem to Moss Motors on multiple occasions (like every time I buy brake shoes) for several years, but they simply ignore the reports and the problem and continue to sell the same bad parts. The Moss Motors parts bear the Classic Gold trade name unique to Moss Motors, but I'm pretty sure this problem is not unique to Moss Motors parts, as there have been similar complaints for several years from a lot of other people.

If people would report the sources and manufactures of other similarly undersize brake shoes, I would like to post that information here. I would also be happy to post the sources for good parts that would be the right size to provide good brakes for a full service life.

Addendum, June 30, 2018:
I have now been bitten by this problem too many times. Brake shoes I have been buying from Moss Motors for the past few years have always been undersize. Using good brake drums (10.00" inside diameter), when the new shoes are installed the MGA adjusters go all the way to end of adjustment range before the brakes are serviceable. Rear brakes are still a little loose. Front brakes are on one of the last two notches of the adjuster when properly adjusted the first time. The brakes cease to be functional when the linings are about 30% worn and cannot be adjusted again.

This is a worse problem for rear brakes that have only one adjuster cam. I last replaced my rear shoes on 3/25/18 with 00,744 miles showing on the odometer. Today it has 07,732 on the odometer, and the parking brake is just about useless when the shoes cannot be adjusted (after only three months use on the new brake shoes). I can't be buying new brake shoes every few months because Moss is supplying parts unfit for the application, so I will now have to find a different supplier for these parts.

As of August 2009 I had in my possession two brands of brake shoes, Lockheed with riveted linings and ABS with bonded linings, and both of those were correct size shoes. Not sure if they are still a good recommendation today, but must be a better bet than known bad parts.

Addendum, August 10, 2018:
Installed County brand (R18G8526 - 4-shoes) brake shoes on the rear today, and they are even worse. Adjuster ran up to the last notch, and the shoes did not even touch the drums. Parking brake hardly works at all at full lever travel. The lever in the slave cylinder hits end of travel. Then the hydraulic primay piston in the slave cylinder hits the lever, and the rear hydraulic brakes also do not work. This is a dangerous situation to have no rear brakes on the car. These faulty brake shoes should be avoided. Do not drive the car in this condition. See photos and notes at http://mgaguru.com/tales/mobile102.htm#brakes

Addendum, October 12, 2018:
Bought more brake shoes of different brand from Custom Spares Ltd in Brewster NY. These measure 4-1/4-inches high at center of the arch without the adjuster in place, so looking good. They are part number B5059. On the edge of the lining material is printed "FASA-OBX-FF". Stay tuned.

Addendum, October 25, 2018:
Finally installed the good brake shoes from Custom Spares Ltd. These were actually a hair oversize, so had to grind a smidge from the heal of the shoe frame to fit inside the drums. They now come to snug adjustnment against the drums on second notch of the adjuster when new. See photos and notes at:
http://mgaguru.com/tales/mobile107.htm#brakes

Addendum, January 28, 2021:
There was a report from Greg Reynolds in Minnesota that Moss Motors may have finally sourced some MGA brake shoes in the correct size, so the brakes may actually work. Apparently they fit with only minor tweak of the adjusters. No markings on the parts, but the label on the box tells the story.

Addendum, April 21, 2022:
On April 20, 2022 Peter Ryle in Peterborough, CAMBS, UK wrote:
"I tried adjusting up the rear brakes to get the drums to lock - with the adjusters fully rotated there was only slight dragging of the drum - I could still turn the drum by hand, and could not get it to lock. .... I bought the shoes from MGOC, whom someone had reported previously were the right size, but I am now not so sure. They came in a box branded as Powertune and Made in Taiwan".
On April 21, 2022 Peter Ryle wrote:
"The box that the shoes came in carries the number R18G8526. The drums measure exactly 10 inches across all round, so they seem fine. The shoes however, are only 4 inches tall - should be 4 1/4 according to Barney, so I definitely have undersize shoes. So, do not buy Powertune MGA brake shoes ! I'll return them to MGOC".

So four years after my initial report (and several years after first notice of this problem), such undersize brake shoes are still on the market. Now it appears to be more than just selling off inventory. I suppose someone is still manufacturing these parts as undersize and faulty. Let the buyer beware, as this problem may be around a lot longer.

Addendum, August 26, 2023:
Just installed all new brake drums and shoes and adjusters and masks on my MGA. All parts came from Scarborough Faire. The "standard" brake shoes, part number M57, as noted have 3/16" thick linings, which I suspect are sub-standard thickness. Front adjusters went up 8 clicks (of 18 clicks max) for shoes to touch the drums. Rear adjusters went up 14 clicks (of 18 clicks max) for shoes to touch the drums. All bad. I finally gave up and shimmed the adjuster masks 1/8" in front and 1/4" in back to get the adjusters to work in order to use these faulty (undersize) brakes shoes. See shimming process