New rotors and factory pads - brake pedal hit floor / long stopping distance

[CrystalRedTintcoat]

Hi,

I just returned my SS 1LE to the stock configuration by removing the squeaky hawk HP+ pads and replacing the rotors with brand new Chevy factory rotors. Basically I'm going to keep the previous pads and rotors for track days and use these new rotors and original pads for street driving.

Now to my question or situation.

When I retracted the pistons I opened the brake reservoir and didn't notice the fluid level increasing. I should tell you that I didn't open the bleeder valves on the calipers.

When I finally got in my car and started it the pedal went to the floor for several tries. Then it hardened up but it just doesn't feel right:

1) it seems the pedal is spongy and requires that I press it way lower than before.
2) the stopping distance is really prolonged. Keep in mind these are brand new rotors. While I did bath the new rotors in brake cleaner before installing them I did not rough them up with sandpaper or anything like that.

Will this fix itself or did I mess up the master cylinder seals by not opening the bleeder valves?

Thanks.

[Magilla gorilla]

Sounds like you got air in the lines...will need to bleed your brakes...

[CrystalRedTintcoat]

Thanks. Is that dangerous? I took a spin down the freeway.

How would air have gotten in there given I didn't open anything up.

[OK2DRUL]

I agree with Magilla that the system probably just needs bled. I would avoid driving it until you bleed the system. If you have an extra person, it should take 30 minutes tops after the wheels are off.

[Norm Peterson]

I'm more concerned that you chased dirty fluid back up into the ABS unit than any consequence involving the master cylinder. I'm not sure what dirty fluid in the ABS unit will do to it or its operation, other than I doubt it would be anything good. You need to purge that all out, which I think will involve a scan tool to cycle the ABS.

I always crack the bleeder on an ABS car when retracting the pistons. I know I'm going to bleed the brakes when I'm done anyway just to chase however much of the dirtiest fluid remains out of the system entirely.


Norm

[Norm Peterson]

Originally Posted by CrystalRedTintcoat

1) it seems the pedal is spongy and requires that I press it way lower than before.
2) the stopping distance is really prolonged. Keep in mind these are brand new rotors. While I did bath the new rotors in brake cleaner before installing them I did not rough them up with sandpaper or anything like that.

Don't forget that you've just swapped out pads with pretty good bite for pads that aren't quite as good. Getting used to track pads has probably skewed your perception of what all pads should feel like. Do you remember the first time you used the HP+ fairly hard, and how that compared to the OEM pads that you'd been used to before that?

If it helps any, Carbotech pads are clearly gentler on rotors than HP+, at least the XP8 which is kind of an entry-level track pad like the HP+. Supposedly swapping among the various Carbotech pads can be done without swapping or doing anything special with the rotors, but if you don't do a whole lot of street driving between track days it seems hardly worth it to bother. Just do a bleed when you're checking for adequate pad thickness shortly before your next track day.


Norm

[Rob@WretchedMS]

the HP+ pads grab a ton better than the stock ones, so Norm may be right about the difference being from you getting used to the added stopping power.

however, i would bleed them just to be sure,
Also triple check that the pads are installed right, that the pistons are contacting the pads correctly, and that the pads are not bound up on the slider areas at all.

[CrystalRedTintcoat]

@Norm: I appreciate your inputs. I think you are saying to use street and track carbon tech pads which have the same chemicals and don't require turning the rotors between pad swaps.

Also, are carbon tech street pads quiet?

[CrystalRedTintcoat]

Originally Posted by Rob@WretchedMS

the HP+ pads grab a ton better than the stock ones, so Norm may be right about the difference being from you getting used to the added stopping power.

however, i would bleed them just to be sure,
Also triple check that the pads are installed right, that the pistons are contacting the pads correctly, and that the pads are not bound up on the slider areas at all.

Hi. What is bound up on the slider areas?
FWIW, I ensured the pad retaining pins are going through both the piston shield and the pads and seated inside the calipers.

[CrystalRedTintcoat]

Originally Posted by Comrando

Same here, except it doesn't matter to me if it has ABS or not.
It makes no sense to push old brake fluid back towards the master cylinder.

So you change the brake fluid with every pad change? Every time you retract the pistons?

[Rob@WretchedMS]

Originally Posted by CrystalRedTintcoat

Hi. What is bound up on the slider areas?
FWIW, I ensured the pad retaining pins are going through both the piston shield and the pads and seated inside the calipers.

just be sure that the pads can move with the pistons retracted, i'd be very surprised if this was an issue, just wanted to give you all of the options.

[Norm Peterson]

Originally Posted by CrystalRedTintcoat

@Norm: I appreciate your inputs. I think you are saying to use street and track carbon tech pads which have the same chemicals and don't require turning the rotors between pad swaps.

Also, are carbon tech street pads quiet?

Apparently the Carbotech pad compounds are all compatible with one another, but I have no knowledge about how that is accomplished.

I don't personally have any Carbotech street pad experience because I went straight from a Hawk HP+/HPS combination to XP8's at both ends, XP8 representing the beginning of their XP track pad series.

FWIW, XP8's dust slightly less than HP+ but quite a bit more than HPS. As for noise, that seems to be a sometimes nothing, sometimes quite a lot kind of thing, which I guess isn't bad at all for track pads. My wife hears noise more often than I do because her high-frequency hearing is better than mine.


Norm

[Rob@WretchedMS]

i don't have any first hand info on Carbotech street pads either, i stopped selling them before i could find out.

[CrystalRedTintcoat]

Originally Posted by Rob@WretchedMS

just be sure that the pads can move with the pistons retracted, i'd be very surprised if this was an issue, just wanted to give you all of the options.

Thanks. Yes. With the pistons retracted the pads moved around easily. I had to align the piston shields, pads and caliper pin because they moved so much.