brake vibration

[PeteB]

Might help the OP if she is still having trouble:
https://www.matthewsvolvosite.com/forums ... 37#p339337

My guess is that one shoe in the rear calipers is frozen so that pressure is only
applied on one side. That is what was wrong with ours and it made a droning sound
and very strong vibration.

[JNavas]

And rotor materials are not just cast iron -- better rotors are sophisticated alloys and other materials.

... and when was the last time you installed carbon-carbon or ceramic matrix on a Volvo? "Sophisticated alloys" and "other materials" aren't used that much in brake discs, buddy.

With respect, if you do some actual research, you'll learn that manufacturers do in fact use different alloys in different rotors, and that the better alloys are in fact "sophisticated".

p.s. My name isn't buddy. Perhaps you have me confused with someone else.

[Sommerfeldt]

I'd love to see that "research" you're talking about, where they make "sophisticated alloys" and "other materials" a part of regular brake discs/rotors.

Carbon-carbon and ceramic matrix (ceramic composites) are the two other groups of materials that are used in automotive brake rotors. There aren't any "sophisticated alloys" and "other materials". My best guess here is that you think that G3000/G4000 are "sophisticated alloys", but they're simply nodular cast iron with different carbon specs.
It's all grey iron, buddy.

Like I said, I'd love to see it if you know of some manufacturer that use "sophisticated alloys" and "other materials" in their brake rotors, other than the carbon-carbon and ceramics.

- S

[JNavas]

Example: Centric Premium High Carbon Alloy Rotors

Centric 125 Series High Carbon Alloy Brake Rotors contain an advanced metallurgy that greatly reduces the possibility of pad squeal especially with higher friction, European style brake pad compounds. Proprietary Molybdenum and Chromium alloys resist rotor cracking during high performance use or repeat stop situations. This alloy also increases the friction couple improving brake performance and stopping power. Increased Chromium and Carbon content is also more resistant to oxidation.

p.s. Like I said, my name isn't buddy, and if you can't muster common courtesy, then I'll pay no further attention to you.

[Sommerfeldt]

Jesus Christ, John. That's still cast iron! Just because these guys dress it up with fancy words, that doesn't mean it's "sophisticated alloys". It may very well be that these people use their own variables on chromium, carbon and molybdenum, but all of those are normal alloying elements in cast iron.

I think you might benefit from researching what cast iron actually is, and what it contains. Brake discs/rotors are cast iron, carbon-carbon or ceramic matrix. Some aerospace applications have also used beryllium, but that gives off toxic dust, worse than asbestos, so I don't think we'll see those on cars any time soon.

- S

[tryingbe]

Vibration while braking? Your engine mounts might be bad.
https://volvo850wagon.wordpress.com/201 ... brakes-on/

[JNavas]

Jesus Christ, John. That's still cast iron! Just because these guys dress it up with fancy words, that doesn't mean it's "sophisticated alloys". It may very well be that these people use their own variables on chromium, carbon and molybdenum, but all of those are normal alloying elements in cast iron.
I think you might benefit from researching what cast iron actually is, and what it contains. Brake discs/rotors are cast iron, carbon-carbon or ceramic matrix. Some aerospace applications have also used beryllium, but that gives off toxic dust, worse than asbestos, so I don't think we'll see those on cars any time soon.

It appears we'll just have to agree to disagree.

[Sommerfeldt]

It appears we'll just have to agree to disagree.

Cast iron's properties are changed by adding various alloying elements, or alloyants. Nickel is one of the most common alloying elements because it refines the pearlite and graphite structure, improves toughness, and evens out hardness differences between section thicknesses.

Chromium is added in small amounts to the ladle to reduce free graphite, produce chill, and because it is a powerful carbide stabilizer; nickel is often added in conjunction. A small amount of tin can be added as a substitute for 0.5% chromium. Copper is added in the ladle or in the furnace, on the order of 0.5–2.5%, to decrease chill, refine graphite, and increase fluidity.

Molybdenum is added on the order of 0.3–1% to increase chill and refine the graphite and pearlite structure; it is often added in conjunction with nickel, copper, and chromium to form high strength irons. Titanium is added as a degasser and deoxidizer, but it also increases fluidity. 0.15–0.5% vanadium is added to cast iron to stabilize cementite, increase hardness, and increase resistance to wear and heat. 0.1–0.3% zirconium helps to form graphite, deoxidize, and increase fluidity.

Or, you can just be an adult about it, and realize that you're not always right, and acknowledge it when you've made a mistake.

- S

[JNavas]

Or, you can just be an adult about it, and realize that you're not always right, and acknowledge it when you've made a mistake.

Good advice. But I'm guessing that irony will be lost on you.
Entertaining as this silly back and forth has been, I will not respond further,
leaving you free to have the last word you so desperately crave.

[cynlim]

Thanks all for the tips, the vibration went away by itself without me doing anything. There were some grease (from the torn drive shaft boots) which an apprentice at the workshop tried to clean up using a high pressure water hose when I took the car back. The water somehow got into the brakes. Or it could be he leaked some brake oil onto the wheel hub while changing the brake oil. Trust an apprentice to do a simple job!