Disc Brakes
Glue? Rivets? Both?
Has anyone discovered a problem where the friction material has come loose from the backing plate, either all of some of it?
I’ve never seen that happen my-diy’er-self, Just curious if it ever does is all.
Biggest reason I know of is moisture getting in between the friction material and the backing plate and rusting, the rust expands and forces the 2 materials to separate.
1 Like
My 60 Morris minor was the only one I saw with rivets and the shop wouldn’t use them. I’ve never seen glued pads or shoes come apart.
Edit: I didn’t know they still did rivets but guess it’s one more thing to look at putting the pads on
We don’t get the corrosion and rust that other places get, but I have seen bonded and riveted pads and shoes friction material come apart/loose from the backing plates from over heating, I think (no real prof) that riveted is better than bonded, but bonded seems to last a little longer due to not having the rivet protruding past the plate… I have pulled new bonded shoes out of the box and the shoe friction material was already loose… That being said small drum brake shoes are very thin to begin with so riveted would only make them least less…
I had it happen once. It was long ago, but I think it was the rear brake shoes on my '97 Escort. IDK why they separated or what was supposed to bond them. They were very old. Lots of highway miles, and I’m not a heavy braker, so I can end up with rear brake shoes for what seems like millennia.
1 Like
Another cause is if they’re allowed to get too thin, then heat builds up and the adhesive fails.
2 Likes
Glue or rivets or both can bond the friction material to the backing plate.
Heat or corrosion can shear the lining off… disk brake pads or drum shoes. Clutch lining, too.
I have done all three seperately at least once.
2 Likes
I have had bonded pads come apart before they wore out. Never happenned to me with rivited ones. Been a long time since I got a eivuted pad. Our brakes around here don’t usually wear out, the roas salt bindes them up first. Since you have to take them apart anyway, it is just better to put in new pads and rotors.
1 Like
When I lived in Ohio, I replaced brakes because the rotors were badly corroded. Any car that didn’t get a lot of miles lost the rotors before the pads.
What part of it corrodes? The friction surface is always kept shiny from the brake pads. Rotors are so thick I would assume the rest of the car would be gone before that was an issue.
Nope…
aaaand really Nope!
If you don’t drive a lot and some of it is on salted roads your rotors start to look like this… The corners rust off, the surface pits and the friction surfaces become a lot smaller and braking becomes pretty ineffective.
2 Likes
Nostalgic photo from Ohio?
My front one is clean but just grooved so I bought new ones. Haven’t decided on the rear yet.
Nahh, just grabbed one off the interwebs! 
But that IS what they look like…
1 Like
Mine look like that too and the pad surface looks bad with embedded rust. The rotors and pads seem to get just as rusty, reguardless of price. The last set of pads and rotors were cheapo Ebay, Detroit Axle ones for $526 they lasted as long as anything else.
Some of those pads rust because there is steel wool in the friction material. It is used to clean the rotors. You used to be able to use copper wool to make the rotor wear less but it has been outlawed.
1 Like
Metallic brake pads…
Metallic brake pads are comprised of anywhere between 30% and 70% metals including copper, iron, steel, or other composite alloys . These various metals are combined with graphite lubricant as well as other fillers to complete the brake bad.
Metal can rust…
In addition to the surface getting badly pitted or unevenly worn, I have had vented rotors where the vanes or ribs between the two rotor surfaces rust out and collapse under braking pressure. I once saw a guy roll into a shop with the friction surface part of the rotor rusted off the center hub. He complained about a noise all the time but worse when braking. Ya think? Even better, he declined repair after hearing the cost of it and drove off like that.
1 Like