Hey All,

I went metal to metal on my front passenger's side brakes the other day. Parked her for a week while pads and rotors came in (went with some almost brand new OEM and Girodisc Magics).

Here's what I found on the inside pad.




Now, the outside pad and both the pads on the driver's side look like this:



Thin, but not hitting the squeakers, yet.

Just wondering what could cause uneven pad wear. I am planning on having my calipers coated and I'll replace the seals and dust boots. I'm not leaking any fluid. Fluid has been bled and wasn't particularly dirty.

Thanks! And on a side note, they were Autozone pads.... glad to get those off the car.

Additional info. These pads were on the car when I bought it. I've put 20k on them.

 

The likely culprit would be a sticking piston in your caliper. There is enough hydraulic force from the brake system to push it out but not enough force to slide off the rotor when the braking event has ended. Does the lower inside piston on the passenger side push in easily?

 

They both compressed easily enough when I was spreading it.

I really want to rebuild them and have them coated. Just need money!

BTW, I still want your suspension if you have it. Things just keep coming up!

 

our braking systems suffer from pad knock back. before braking hard into turns, i tap the pedal quickly and let off. that resets the pads and gives me a better pedal feel.
maybe that could be part of the reason?

 

I had a similar thing happen on my last set of pads and spoke with someone at Girodisc about this to get their feedback. Now this was a year ago so I don't remember exactly what he said but apparently its pretty common and isnt a result of a sticking piston (which was my first thought too)

Instead, I believe it was something about the way the fluid enters the calipers on the inside and then is bridged across so the inside pistons tend to push out a little sooner since the fluids doesn't have to travel as far. I may have butchered that explanation but believe its something along those lines...

Also, another thing to consider is that there tends to be more heat on the inside vs the outside since thats where the caliper attached to the knuckle so heat can get trapped there. Once a pad gets outside of its ideal range pad wear is greatly accelerated.

My current pads are doing the same thing so I think I may just swap then inside out assuming those feeler gauge thingies dont get in the way. Of course I could just rip those off but yeah...

 

wouldn't that act as a heat sink and transfer the heat out? that's the sole reason i want 2-pc rotors; i want to keep heat away from the wheel bearings.

 

I would get ducting if you are afraid of that

2 piece rotors are more of a gimmick than anything

The efficiency of the cooling, ring replacement and rotational mass advantage is marginally efficient

Get as much air moving to the center of the sub where the veins draw from inside to out to cool the rotor

 

+1

I check my pads (cuz they are pricey) and rotate like I do tires:

Inside/outside; outside/inside
left/right caliper; right/left caliper

 

interesting. i can't find it now, but i read an article where they compared heat transfer and the temps showed they did a better job at keeping things cool. then there is the rotating mass advantage.
hm. maybe i should research again.

 

For the cost of 2 piece rotors, you are going to get substantially and dramatically better performance from ducting

 

ducting always comes first.

 

When my Evo 8 was new the OEM pads showed uneven wear and there wasn't anything wrong with the calipers unless they came from the factory that way. I've had magic pads on for the last 60k, same shims, and they show no uneven wear. So, it is just the pad.

 

The benefit from a 2 piece disk
a) Weight
b) Zero coning

Comparing a 2 piece vs single is very difficult

Anyone using a vehicle for circuit driving should consider, first upgrade the pads, second upgrade your fluid, and third add cooling ducts.

Also some advice, its easy to do, but don't forget about the rear temperatures too


To the OP: On a fixed caliper making clearance between the rotor and pad must rely on piston seal roll back. If the pad sticks to the abutment because of grit etc, it can cause drag. If any of the seals are going bad, it can cause improper roll back, decreasing the normal clearance.
Also, brake disk temperature outside vs inside plate variation can also cause this type of pad wear.