Brake pedal travel

[tmoretta]

My completed 818S is exhibiting a brake problem. Firstly, the pedal requires a good amount of effort. Considering how I don't have power brakes I can deal with that. More importantly, as I brake, the first application causes the pedal to drop more than the second application. The pedal definitely is higher on the second or subsequent pushes. I know this because I have modified (blocked up) the brake pedal to allow heel toe downshifting which is impossible on the initial push. Would air in the lines cause the pedal to depress differently on first and second push? Do I need to do some more bleeding?

[JeromeS13]

Yes. Sounds like air in the system. For the pedal effort, what kind of pads are you using? I found that using Centric Posiquiet pads, they didn't have very much bite and required a good amount of pedal pressure. I switched over to Hawk Blue pads for the track and they have seemingly 2x the amount of bite, even when cold. So I left those installed all the time.

[tmoretta]

I am using Hawk HP+. Figure good compromise for street and occasional track.

[sbak]

What brake calipers are you using?
If you're already using a good set of new or rebuilt 06' or newer WRX 4/2pots, must be air in the lines, however if you don't then read on.
I had a 2005 Forester XT and a huge complaint were the brakes feeling the same way; no amount of bleeding, switching to braided brake lines would fix it. It is just the design of the "stock" calipers. I changed mine to new set of 2006 WRX 4 pot/ 2pot calipers and it fixed the problem. Many owners went with Brembo, Rota, Cobb(they no longer sell theirs), Wilwood. You can find a lot of information about this on the forester owners forum.

[tmoretta]

I am using the rebuilt calipers from a 2002 WRX donor car. So, it could be that these calipers are designed to require more pedal travel on first push? I will try re-bleeding. Anyone else have experience with this? I carefully re-bled all four calipers. Problem solved, although without a brake booster, the pedal is very firm (hard to depress).

[sbak]

It might still be the calipers, I say this because the 2002 WRX used a 'pull one side' caliper on the front and back, same as was used on most of the other Subaru models except the STI. That's why I said 'design of the 'stock calipers'. The 05 FXT was a much more powerful car yet it still had the same braking system. The mushy pedal on first push is normal.
The later model WRX came standard with a 4 pot caliper on the front and a 2 pot on the rear. This design squeezed both sides of the rotor at the same time against the rotor. This doesn't allow the rotor to be pulled or pushed to one side to make contact with the pads. This is more or less why the pedal seems mushy on first push, according to all the information I could get from both the forester forums and Naisoc.

[STiPWRD]

It might still be the calipers, I say this because the 2002 WRX used a 'pull one side' caliper on the front and back, same as was used on most of the other Subaru models except the STI. That's why I said 'design of the 'stock calipers'. The 05 FXT was a much more powerful car yet it still had the same braking system. The mushy pedal on first push is normal.
The later model WRX came standard with a 4 pot caliper on the front and a 2 pot on the rear. This design squeezed both sides of the rotor at the same time against the rotor. This doesn't allow the rotor to be pulled or pushed to one side to make contact with the pads. This is more or less why the pedal seems mushy on first push, according to all the information I could get from both the forester forums and Naisoc.
The 02-05 calipers are a 'floating' design, i.e. the calipers are free to slide left-to-right on their brackets. So even though the piston/s are only on one side of the caliper, the caliper gets automatically centered on the rotor when pressure is applied to the pads. I'd say the mushy pedal is not normal and is most likely due to air in the system.

[tmoretta]

That is what I thought. I have owned many cars (9 BMW's included) that had "floating" calipers. Never a problem.