What's the Limit on Disc Brake Pads Before Metal on Metal? (1 Viewer)

[Brian Serene]

My understanding is that 2 MM is when pads should be replaced. I'm just curious how far down the pads can wear before reaching metal on metal? One half MM, One Quarter MM?
Thanks In Advance
I know there is supposed to be a warning signal, however, I have heard that this device doesn't always work.

 

[Jay H]

Well, if you hear metal on metal scraping or start seeing groves in the rotors, you've probably gone too far! I don't know about the professional opinion but I would typically replace my pads if it's within 2mm of the end. But then they do normally have a small AL....tab thiny that will start to rub if the pad wear gets pretty thin... At least the ones that I've bought did..
Jay

 

[Brian Serene]

Well, if you hear metal on metal scraping or start seeing groves in the rotors, you've probably gone too far! I don't know about the professional opinion but I would typically replace my pads if it's within 2mm of the end. But then they do normally have a small AL....tab thiny that will start to rub if the pad wear gets pretty thin... At least the ones that I've bought did..
Jay

Thanks for your suggestions, however, will metal on metal not happen as long as there is ANY pad left?

 

[schan1269]

Yep, cause of the rivet holding the clips on. But that depends if the pads just "sit" in the caliper...or are held in.
The rivet in most pads occurs around 1mm. But since you haven't said what car or even the current pads...we have no clue. Some pads(depending on size/weight of the vehicle) the rivet occurs at 3mm.
The rivet is what does the damage to the rotor.
As fast/easy as it is to change brake pads. There is never an excuse to bite the rotors. I have a Miata, Taurus SHO(89), Ford F250 and a Chevy Astro.
On all 4, the brake pads can be changed in 20 minutes. That includes jacking the car up and putting it back down. If you can "change a tire"...you can change pads.

 

[Steve Schaffer]

Toyota OEM pads didn't have rivets as of '06 when I quit working at the Toyota store service dept. They did have metal tabs designed to squeak harmlesslly against the rotor when the pads got too thin. This squeak was usually ignored by the driver. Letting pads get thinner than 2mm is false economy.