Hello everyone, need some advice about the uneven brake wear. I am planning on doing 1 track day a month for the next 12-18 months in the Z, but I've some braking issues come up. I did a full track day at Bedford GT on Monday. New OEM pagid pads went in the week before (all i could get my hands on at short notice), however I perhaps could have done a better job bedding them in. The old pads that came out, had about 1mm difference between outer and inner pads, with inners at about 3mm.

In the morning session as I started pushing on (max of 4 hot laps), I started to feel the brake pedal soften a little, no worries I came in. Front rotor temps in the morning were about 210, in the afternoon about 280 deg C. But on my very last session of the afternoon, in fact I think it was the last lap, the peddle went pretty soft, and I could hear the brakes groaning, the pads had hit the metal wear tab & groaned all the way home! The following day I removed the wheels to get a good look at the pads. There is virtually no inner pad material left at all, and the inner rotor surface has as a nice rusty lip on one side and scored on the other.















Bedford GT circuit is 4.1 miles long with 6 hard braking zones from high speed (100+ down to 35, 45, 30, 60, 35, 35 in that order) so i can understand going through a set of front pads and the fade issues on a full day there, with the stock Brembo brake rotors, pads, lines and fluids. Does that sound reasonable?

But the bigger issue is the uneven wear of the inner and outer pads. There is 3mm of brake pad on the left outer, and maybe 4mm on the right outer. The above pics show virtually now pad material left on the inner pads. This is where i really need people powers of reasoning and intelligence!! So I'll give as much info as possible:

- Both front rotos rotate freely
- On my way home after the track day i was concerned that the groaning could be a stuck calliper, so I pulled over and checked the temps, both rotors were equal at about 80 deg C
- The excessive wear is on the inner pad on both sides. before the track day i check the rear pads, and they had similarly uneven wear, but much less noticeable, <1mm difference
- After i had the pads replaced prior to the track day, the brakes squealed like a total pig at low speeds coming to a stop, i presumed the mechanic had just been stingy with copper/anti-squeal grease.

What Conclusions can be drawn, what can be excluded?
Can i exclude a stuck calliper, given the above additional points. I've had a stuck calliper on the BMW 330i (twice!) and the braking was juddery and one rotor/calliper got much hotter in everyday driving.
I've read on line in other cars that it's sometimes due to inadequately greased slide pins, bent slide pins or corroded pins.

I'm going to get the front rotors & pads, as well as all lines and brake fluid uprated, but need to know whats going on before shelling out £££ on uprated brake components.

I might have a go at putting the old pads back in, and so be able to see how easily the 4 pistons on each calliper go back in.

All opinion and thoughts on the above problem would be greatly appreciated

 

Probably not a stuck caliper or your pads would have been toast, and probably more wear on one side of the car.

Sliding pins could be getting stuck. Althought this seems unlikely because you are having the exact same wear pattern on both sides.

Sounds almost like your inner pads are getting hotter than the outer. Do you have brake cooling ducts installed? And are they favoring the outer pad?

 

No the car is otherwise stock, no after market cooling ducts installed. As I've been reading about, and posted elsewhere as well, I'm starting to think it may just be a 350z trait that the inner pads wear faster than the outers??

 

So I thought I would stick my old pads back in just to allow me to get the car to the garage, etc

Removed the left front pad and this is what i found, top pic is the pagid pad that was used at the track, bottom pad is the Brembo pads that came out prior to the track day. Note how the brembo's have a backing plate (prob aluminium) which minimise heat tranfer to the piston and hence fluid. The result with the pagids is the piston shape has become heavily imprinted on the back of the pad, to such an extent that i was able to force my finger through.







BUT worse was the front right!! I'll let the pictures tell the story, this is how the pads came off, ****!!:





Cleaned the inner bores as best i could with disc still in place, but when i replace both discs and pads in the coming days, I'll give the piston bores a gentle clean with some fine sand paper and iron wool.

Good news: all pistons went in easily, and its nice to realise that the pads can be changed without having to remove the caliper unlike in the 330ci and most BMWs.