The Stovebolt Site Forums The Shop Area Driveline Squealing brakes, again and again?

So ya ever have a big old garbage truck pull up next to you at a stop light and hear it
coming long before you ever see it by it’s squeallllllll???
Well taint only big old trucks that are plagued by it. I’ve had the embarrassment of
squealing brakes with me on and off for years.
Now before you go and look up all the symptoms on the internet for to respond with a
diagnose, let me say, that I’ve been doing brake jobs on my own and other cars
since I was a pre-driver teen. Pop was an old school mechanic and taught me brake
work before I ever had my own cars, and I’m now 73 years into it.
This is the first one that I’ve had this severe of a problem with brake squeal. Let’s get
clear that there is a difference between brake squeak and brake squeal. Brake squeak
is what you hear when you’re sitting still in the drive way you hear a squeak when you
apply the brake as all the dry metal parts expand out to meet the drum or disc.
Brake squeal is the steady screeching you hear when rolling to a stop.
Number one cause is usually glazed lining and is easily remedied by sanding the shoe
with some 80 grit to remove the dust that is been packed into the surface of the lining. I
also rough up the drum and check that they have no hot spots or high spots and that
they are wearing evenly.

So….the lining that I used on my ‘50, 3600 Huck brakes, which I believe came from one
of our old truck vendors, seem to glaze up after a few weeks driving, which translates
into six or eight hundred miles.
The drums are round, (indicated them), they are in good condition, they were turned
about .020” when I did the brake job, turned them myself and they do not pulsate when
applied. They are not distorted and the backing plates are not bent either, the brake
shoe return springs are not weak or broken and the front wheel bearings are in good
shape and are properly adjusted.
The linings are dry, not saturated, nor do they have any signs of contamination.
Once they begin to glaze up they squeal cold or hot equally well.
When I pull the drums to de-glaze them, there is not an excessive amount of dust, in
fact there is very little dust, which suggests to me that the lining may be too hard of a
compound.
With about 15K on this brake job, there is still over ¼” of lining left and there wasn’t
much more than that when it was new.
The leading edge of all the shoes, I’ve chamfered back about ¼ to 5/16”.
The squealing develops at about the same time on both the front brakes after servicing
them.
The rears have not given me any problem, I suspect that they may be a different
compound, quite possibly from a different supplier.

So what do you old experienced mechanics think, maybe just as simple as too hard of a
compound???

Denny Graham
Sandwich, IL