STi-owns-evo

iTrader: (4)

To start, what's done to my car in terms of brakes:

'02 WRX with
- Subaru ABS ECU replacement
- StopTech SS lines
- TiC MC Brace
- Subaru 4-Pot calipers currently with Hawk HPS pads
- H6 rear upgrade with StopTech SP pads
- IIRC, Motul RBF600

Whenever I start my car (or after the car sits for a while) the first time I press the brakes, it travels a tiny bit further than any other time I press the brakes. If I forget, that millisecond gives me a heart attack when the normal braking point doesn't start slowing down the car, and it needs a little bit more pedal travel to brake. However, after that initial press of the pedal, everything firms up and it's back to normal until the next time the car sits for a while and I fire it up again. I thought, if air was in the lines, the pedal would always bit a bit mushy and might travel a bit further, not just the first press. Am I wrong, and is this be the culprit? I need to change my front pads soon, so I may as well do a bleed anyway. I'm just looking for other possibilities of what it might be.

Looking on google, a similar problem can be caused by a bad wheel bearing, as a very slight wobble in the wheel might press the pads out a bit. However, I'm inclined to rule that out since that should only happen if the wheel is turning, so the problem should not occur when the car just sits. Correct?


Second question:

Part numbers for StopTech SP front pads for the 4-Pot.


The left diagram is for the 300ZX that people say has the same pads as the Subaru 4-Pot. The right diagram is for the '06-'07 WRX that came with 4-Pots. The diagrams seem to be different, mainly the diagonal slot on the 300ZX pad. Does this make a difference?

Heedz

iTrader: (51)

Are they bled well?

wombatsauce

iTrader: (7)

I had, I think, the exact same issue symptoms on my 2002 sedan. Stock brake hardware front and rear, with added StopTech rotors and pads. Not 100% sure on the pads as there was a mixup with the shop and we are not sure if new pads were installed, or if the set of new R4-S pads in my trunk were installed.

With mine, it got to the point that I habitually made a "tap-tap" on the pedal before slowing when the car was cold or I had not driven it for a while, to bring the pressure up before braking. I as well attributed it to air in the system. I asked my shop to bleed the brakes again. In the process, he found that my right front caliper slider was not moving smoothly. Now, it's gone and I do not have to "tap-tap" the brakes first to get that firm pedal feel.

While this was happening, my front rotors did not seem to be wearing in right, and there was also a slight wobble on light braking. I tried "braking them in" one time and that did not work as it had a million times before as well. Now, after the bleed and the caliper slider re-packing, the front rotors are clearly wearing in and actually have a bit of a lip. The rears on the other hand are why I am in this forum using the "search" function.

Oh - I just remembered, we also replaced the master cylinder before re-bleeding. It was showing signs of impending failure, so it seemed to be the right thing to do.

wombatsauce

iTrader: (7)

I finally got an alignment and have been able to USE my car here and there. I commute on the back roads every single day, and have been driving the WRX the last couple days. My brakes suck.

The last time I drove, I noticed a bit of fade and then coming down a long hill, I just tried braking hard to test it - and it did not work very well. I came to a stop and looked at everything and my front rotors were very blued while the rears still looked relatively un-used.

My mechanic did mention something about the rear rotors being "wrong" in that the rotor area was too far to one end of the adjustment range of the sliding caliper, but I have not looked at it myself.

I still don't know what pads are on my car, and I know weird things can happen with different pads front and rear, so I may just try getting a new set of front/rear pads so I know for sure what is in there.

Really wanting to just go with 4/2pots though.

Did you get anywhere with your pedal travel issue? Mine seems to be okay now.