Mystery of the smoking nuts

back to the brakes
do those early brake shoe retainers, cone spring and square foot backplate hook thingy, hold the shoes onto the back plate well enough.

i have 9 inch brakes i rebuilt them with a mix n match of parts from rockauto raybestos if in stock and delco for the rest i.e the mid or higher price stuff

when i put the main springs onto the brake shoes they were so strong that they pulled the shoes out like wings i.e at the mid point of each shoe there was a gap between it an the back plate and no way would the friction material run true with the drum surface

i put it down to crap parts and swapped to 73-onwards pin cup spring hold downs.

you have to buy a bag of washers to make the head of the pin big enough not to pull through the large holes in the back plate but it solved my problem.


either the hold down cone springs or the main springs for the shoes were i presume not to OEM specification or i was sent the wrong stuff. would not be the first time Rockauto provided hours of "amusement" and an excuse for foul language

but you do need the shoes to be held flat to the contact points on the back plate

2 styles of shoe as well. some have a swaged over edge for the contact point, nice and smooth
some have a hard cut edge for the contact point (quite rubbish in my view)
the former would appear to be better as i don't see them wearing as much of a groove or hanging up....

and obviously you need to get the shoes in the right position
leading shoe , front, short friction material
secondary shoe, long friction material, back
i think.....! i always check the book due to knowing i know this, but then doubting myself, and of course with no book to hand i'm doing that again.

but basically you can get the lot wrong 4 shoes and 4 positions to choose from

and you have the vague differences between duo servo on early A body and not duo servo on later. can't see much difference myself, but i believe it exists and the change was early 70s it just a variation in how much shove the leading shoe can give to the secondary shoe when the brakes are on but how this was implemented and applied is lost on me, mine are early brakes and i have nothing to compare to.

Dave