Just changed pads and fluid; brake pedal has more "dead space"

[ryoma]

so I just changed my pads from OEM to Winmax W5 and fluid from OEM to Torque RT700 for an upcoming track day. As I was bedding in the pads, I noticed that I need to push my brake pedal further in, about halfway, before I feel the brakes start biting. Is this due to the RT700 fluid? or do I still have air in my lines? I bled each caliper twice and saw no air bubbles and made sure to flush out all of the old fluid as well. I used up 750ml of brake fluid so I assume I flushed out the entire system (I heard the lines only hold 0.5L).

I also changed out the rear lines to stainless steel, but couldn't get the hard line nut off of the front passenger side, so I left both front lines the OEM line. going to bring it to a shop and have them finish it off. could this be the reason why as well?

the brakes work great though, but since there's that dead space of about half the pedal travel, I need to push in the pedal more to use a little bit of brake. I just want to make sure that this is not me failing on my part and if it is normal lol

[CSG David]

You have air in the hydraulic system. You need to rebleed your brake fluid and make sure the air is out of the system.

[ryoma]

Originally Posted by CSG David

You have air in the hydraulic system. You need to rebleed your brake fluid and make sure the air is out of the system.

alright, I'll bleed it again tomorrow. maybe there was an air bubble trapped in the middle of the lines.

[CSG David]

Originally Posted by ryoma

alright, I'll bleed it again tomorrow. maybe there was an air bubble trapped in the middle of the lines.

Very likely since you replaced the lines in the rear. It's a PITA, but the best way to get all the bubbles out of the system is to flush once. Drive around a little bit to use the brakes and then put back on jackstands...rebleed.

[ryoma]

just rebled the brakes and it feels a little bit better, but still notice that dead spot. guess that air bubble is really stuck in there. I'm out of fluid now so I'll just have the shop finish it off on Monday.

[wparsons]

With better pads and fluid you should feel a massive difference in the pedal, but towards the hard/firm side, not softer or more of a dead spot. Better pads aren't as compressible as stock, so even if the cold bite isn't the same the pedal will feel firmer.

[EAGLE5]

Even with oem fluid and pads, the pedal should be firm when there is no air in the system.

[Reaper]

Update with how you like the w5s when you get the air out.

[CSG David]

Pedal should be rock solid when you attempt to pump it when the car is off and no key in the ignition. If it's not, then you have a problem...

[ryoma]

Originally Posted by Reaper

Update with how you like the w5s when you get the air out.

I'm going out again tonight to bed them in, just waiting for it to be a bit later so there's no one on the road. the air is all out and feels solid when pushing down on the pedal. I didn't bed them in right the first time so I'm redoing it. went 10 times from 50 to 12 then twice from 70 to 50, then once from 70 to 12. then after reading the slip of paper again, it says to do each set (50-12, 70-50, 70-12) 7-9 times, if I'm reading it right lol. I just see some streaks of pad residue on the rotors and the paper says you're supposed to see an even layer of it. so I guess I'm just gonna keep braking until it's all over the rotor.

[CSG Mike]

Originally Posted by ryoma

I'm going out again tonight to bed them in, just waiting for it to be a bit later so there's no one on the road. the air is all out and feels solid when pushing down on the pedal. I didn't bed them in right the first time so I'm redoing it. went 10 times from 50 to 12 then twice from 70 to 50, then once from 70 to 12. then after reading the slip of paper again, it says to do each set (50-12, 70-50, 70-12) 7-9 times, if I'm reading it right lol. I just see some streaks of pad residue on the rotors and the paper says you're supposed to see an even layer of it. so I guess I'm just gonna keep braking until it's all over the rotor.

The speeds aren't as important as getting a good transfer layer. If you're seeing streaks, you're overdoing it, and cooking the pad (and MELTING a layer of pad onto the rotor).

If you smell pads, you need to back off and keep rolling for a bit to let the entire system cool down.

[ryoma]

alright, last time I bed it in, I definitely smelled the pads. I'll take it slow tonight and get some solid braking in.

EDIT: after driving it around tonight, the streaks are gone. There is a light film, but it is also in a streak. not sure if you can see it in the pictures. does that mean the pad is uneven, and I need to wear it down more to get an even film across the rotor? I do notice that the brakes still squeal though, so I'm assuming I didn't do enough braking.