Re: 60mph front brake failure 06 Dyna
In my opinion,this isn't a year/batch problem,more an ongoing quality controll issue.
In the 70's,I was involved in the developement of brake shoe bonding rigs.
(Stay with it,we'll get to pads.:wink
The linings were sprayed with neat glue,and the shoes were shot blasted and dipped in a diluted version of the same glue.
The linings had to cure for 30 hours,the shoes for 5 hours.
On the rig the shoes were pre heated for 2 minutes,then the lining clamped in place for 2 minutes.
Every hour,a pair of shoes from each rig were tested to destruction by forcing a hydraulic ram against the side of the lining.
A good bond was if the lining sheared,leaving a thin coating of friction material bonded to the shoe.
One main cause of failure we found,was if the shoes were left between shifts in the shot blasted state,causing a delay in the dipping stage.
This caused the lining to come away with the glue,leaving an uncoated shoe.
Lockheed pads were made with blanks (backing plates),that had holes in them.The friction mix was pressed into a mould that forced it through the holes.
The friction material was then ground to size,and the blanks painted black.
Many pads these days seem to have no holes in the blanks,and this would sugest that the friction material in formed into pucks,then bonded to the blank.These are still ground,you can see the grind marks on cheap pads from an undressed wheel,but the amount of dust produced would be greatly reduced.This would be a big H&S issue,unless made in India or China.The conditions in some foundaries in China would make your Grandad weep.:frown:
So if I'm correct,if the blanks are left uncoated for a period of time,they will rust,forcing the friction from the blank.The more metalic content in the friction material,the worse the problem,from the reaction of dissimilar metals.