SphinxRacing
SphinxRacing New Reader
12/1/20 11:10 a.m.

Bought a 99 spec miata that came with a bunch of used but good condition brake pads.  They aren't labeled  (i know what brand and compound they are).  so, I'm trying to figure out if there's a way to identify which side they came off of and which pad should be on the inside v. the outside (all front pads).  The normal markings from the piston and caliper aren't helpful since it seems that the pads served duty in both directions (there's an imprint of the piston on 3 of the 4 pads).

This group tends to be very resourceful.  So, figured I'd ask here.

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
12/1/20 11:45 a.m.

measure pad thickness at each end.  end-to-end wear is typically not uniform, as the pad tends to move in the direction the rotor is spinning.  leading end will be worn thinner than trailing end.

SphinxRacing
SphinxRacing New Reader
12/1/20 1:02 p.m.
AngryCorvair (Forum Supporter) said:

measure pad thickness at each end.  end-to-end wear is typically not uniform, as the pad tends to move in the direction the rotor is spinning.  leading end will be worn thinner than trailing end.

So, where the brake is behind the axle (Miata), the portion towards the ground will be thinner, correct?

What do you do if the brake pad is thicker in the middle than the ends?  (which might explain why they have piston marks on 3 of them).

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
12/1/20 6:37 p.m.
SphinxRacing said:
AngryCorvair (Forum Supporter) said:

measure pad thickness at each end.  end-to-end wear is typically not uniform, as the pad tends to move in the direction the rotor is spinning.  leading end will be worn thinner than trailing end.

So, where the brake is behind the axle (Miata), the portion towards the ground will be thinner, correct?

correct

What do you do if the brake pad is thicker in the middle than the ends?  (which might explain why they have piston marks on 3 of them).

I'd replace my calipers and guide pins, and maybe even toss those pads. Normal taper wear is pretty linear from end to end. Having a high spot in the middle means they were tapered in one direction, flipped, and tapered in the other direction. 

 

SphinxRacing
SphinxRacing New Reader
12/1/20 7:46 p.m.
AngryCorvair (Forum Supporter) said:
SphinxRacing said:
What do you do if the brake pad is thicker in the middle than the ends?  (which might explain why they have piston marks on 3 of them).

I'd replace my calipers and guide pins, and maybe even toss those pads. Normal taper wear is pretty linear from end to end. Having a high spot in the middle means they were tapered in one direction, flipped, and tapered in the other direction. 

 

Makes total sense.  Thanks!

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