Squealing brakes

[Cochran]

my truck sounds like a city bus coming to a stop. I have 30,000 miles on the truck and the pads are fine. What should I do? Has anyone tried new rotors and or different pads? I am a little hard on the brakes with 35" tires and my driving style is heavy on bolth pedals.

 

[RJOL]

Had this problem with my 2001. Changed out the front pads and it still squealed at times. Here's how I finally fixed it... (see signature)...

 

[Cummins724]

my truck sounds like a city bus coming to a stop. I have 30,000 miles on the truck and the pads are fine. What should I do? Has anyone tried new rotors and or different pads? I am a little hard on the brakes with 35" tires and my driving style is heavy on bolth pedals.

My brothers 04. 5 did this & we changed over to a set of Fleet pads from Napa on both of our trucks... ... no more squeels. You gotta break these pads in hard after install by riding your brake until they seat. I've actually heated them up to where I saw smoke coming out of them & after a few miles they are good as new. This was before I got my exhaust brake, but now I never have to hit the pedal. Good product.

 

[jelag]

When friction is used as a brake pad or brake shoe its already a cured material and doesn't need breaking in... the squeal if from a high speed vibration associated with glazed friction, dust, or pistons and calipers that don't float correctly... what happens is that the metal to metal contact on the back of pad, vibrates and at high speed it causes the noise... .



You can coat the back of the pads to stop it..... you can pull the pads to de-glaze them, clean out the dust and lube the points of contact between the caliper and the assembly they float on... . These trucks do not have a problem with noise... . I personally own 3 of them... not over 350 K miles between them and have had no problems with them... . and have sold 2 other trucks with over 500K on the two...



If the pads are in good condition, (more than 50%) I try the suggestions above... as you might develop the same problem with your new pads because of another problem...



BTW... we've had the rotors on one truck so hot we cracked a rotor... and cooked out the resin that bonds the pad, causing failure... . (stuck piston in the caliper) and we still had no noise from the brake.....



Hope this helps ... .

 

[Cummins724]

I was told when I bought the pads to run them hard for initial break in. I'm not sure why, but my friend is a mechanic for GM & at his tech classes they told him the same thing. I am not saying that you are wrong & God knows that I am not a expert, but why would they say to do this? It sure seemed to work for our trucks. We changed from semimetallics to the fleet pads & squeeling is gone.

 

[jelag]

Cummins.....



The mechanics in the dealers are not engineers... ... some friction used in industrial products are not cured when we get them. . that allows us to form them into cones, bands circles... etc... the material is soft and pliable and can be scratched, and damaged easily..... We cure it after installation on the product by placing it in an oven and baking it... . time and temperature are controlled for a proper cure... .



Disc brake pads start as ground material that's course in texture with binders and powered resins in the mix... . its pressed at about 600 tons pressure and starts about 5 or 6 times the volume that you see bonded on the backing plate... . as it compresses into the puck..... it forms the pad about the texture of a cookie and about as fragile..... its than placed under pressure in a oven and baked the same way we bake our industrial friction... . Once removed from the oven its ground to dimension...



If you chance the recipe you can change from organic, semi metallic, metallic, ceramic and other buzz words in this industry... . As an example the organic friction works well up to about 450 degrees, full ceramic friction will withstand 1000 degrees but the metal around it will fail... .



This all said... remember that in some cases there is not full contact of pad/brake shoe upon installation... ... parts are worn and surfaces often are not correct. . this means that full contact has not been achieved, and in some cases its taught in brake classes to go out and break in the friction to wear down the small contact patches so that you have fuller contact and better braking..... also a pad or brake shoe installed might wish to follow incorrect groves in the rotor and drum causing it to track like a nut tracks on a bolt. . and often it will snap back... once the surface of the incorrect groves are removed by heat, and wear the noise will go away... . a good example of this is a rotor that was turned incorrectly... too deep or too fast... or one that wasn't turned between pad changes and is damages with rivet groves... .



Geez... almost written a book here... . I need to leave this alone... but I think you get part of the picture of how and why?? Hope this helps. .



BTW we understand friction... we do bridge crane shoes, bands that stop ski lifts, turbines, clutches, Paper machines, and about 1000 truck shoes a week. .



Jim

 

[Cochran]

does anyone have an opinion on powerslot or cross drilled rotors for our trucks?