Not up to my usual quality 
. I have a new phone and the film is a bit shakey.
Not sure if you did place some grease on that adjuster(?) To my mind, grease in brakes isnât a good idea. I think that is supposed to provide a bit of friction to hold the shoes closer to the drum surface? Happy to be corrected by someone with more knowledge 
I think Robin is right. Those little pads are called âfriction padsâ in the XK120 Service Manual and XK140 Parts Catalogue.
I think the way they work is they provide some friction in there so when the brakes go out and then come back in, the friction in the adjuster bars stops the motion in the shoes before the pistons have fully retracted.
But the springs are still there trying to pull the shoes together and compress the pistons.
Do the friction pads provide enough friction force to slightly overcome the spring forces and hold the shoes steady more or less against the drum but not applying pressure against the drum?
Or do the springs slightly overcome the friction force and gradually pull the shoes inwards?
It would appear to me that you would have well adjusted brakes in normal driving with fairly frequent applications of the brakes. But when the car sits overnight the brakes might become unadjusted until the first application of the pedal adjusts them again.
I donât have the self-adjuster brakes so I am curious to understand how they work.
I would like educating on exactly what is going on with the adjusters. The friction pads are very small especially when compared to the force of the springs or hydraulics. It would seem to me it might Crouse a miniscule damping. Once the adjuster bar has moved it will not come back as it is a ratchet. When fitting new shoes I would have thought the ratchet should be reset ? but on dismantling the bar was hard up against the back of the shoe and had no where to go to make the circle smaller.
What have I got wrong, every thing?
Here is a bit of film on my questionâŚ
Ok I was wrong, forgot about the ratchet teeth, now it makes sense.
First, does the drum fit on as is?
If it wonât, then either you have something assembled wrong, like a pin in a wrong hole, or you may have to take a bit off the end of the adjuster bar.
When the piston moves the shoe out, it pulls the adjuster bar and clicks teeth until the shoe is against the drum and it canât click any more. Now your shoe is adjusted, and it wonât go back any more than a part of a click.
The friction pads are what hold the brakes in adjustmentâŚthe ratchet is a safety device in case the friction pads loose their grip, generally due to fluid intrusion. An easy check is to pull a brake shoe away from the wheel cylinderâŚas if you were applying the brakesâŚthen see how far back the shoe retracts upon release. Then, use a small screwdriver to lever the U-shaped ratchet spring away from the serrationsâŚif the shoe retracts any more, the friction pads are not tight enough. The Manual does explain this, in the âPrinciple of Operationâ section, but the wording is quite terse and the true functioning of the adjustment system is missed by many.
The other end of the bar has a hole about 30 thou larger than its pinâŚTHIS is where the slack upon brake release is maintained. The pull-off spring should only move the shoe/adjustment bar assembly away from the shoes by this 30 thou. Thatâs one reason you donât want âslackâ at both ends of the adjustment barâŚtoo much slack. The other reason is the serration(s) would wear out in no time if it/they were âhammered onâ every time the brakes were released.
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Hi Lee, your explanation made me go back and read the âPrincipal of operationâ on the front brake assembly. In my mind the castellated nuts needed to be set so the ratcheted adjuster bars needed to âfloatâ in the friction pads. I was focasing on the wrong end of the adjuster bar! My hat is always off to the Engineers in this world of ours.
Cheers, Mark
â54 120 S676095