[outobie]

Hello I just had the Chevy dealer install brand new oversized SS calipers, rotors and brake lines on the front of my RS

The brake pedal seems to have a lot more travel and feels mushy
Compared to the smaller bits I drove in with this morning.

The mechanic says they feel good.

Is it normal for the larger bake kit to feel squishy like this?

Is it possible for the larger calipers to require move brake fluid so the pedal goes farther?

Car only has 3k miles and has only ever been touched by the deeler

[Alpha1BC]

You might expect a slightly softer pedal due to the larger calipers, but they should still feel pretty firm. I'm assuming this was all felt while driving and not just pushing on the pedal when the car is sitting still, right? If the car stops as well or better than the old brakes but you don't have to push the pedal as hard, that'd just be the new brakes working better for you. Tough to tell if it's actually air in the lines or not based on descriptions since everyone has different expectations when it comes to brake firmness, but a few things you can try if it feels harder to stop with the new brakes are:

1) Burnish the brakes in per the procedure in your manual if they haven't already been. Without that you might have to push the pedal harder to get the car to stop which might give the impression that the pedal is mushy. If this doesn't work, try:

2) Re-bleed the brakes. Depending on how good your dealer is, they might have missed the fact that these calipers have 2 bleed screws each, one inboard and one outboard. If they only bled the outboard, there's probably still air on the inboard side that will make your pedal really mushy and the pedal will be significantly closer to the floor when stopping the car.

If neither of those work you might have to go through and bleed the ABS system and/or the master cylinder, but I'd bet it's something less serious than that.

[PolynesianPowerhouse]

I switched from single pistons to the 4 piston brembo setup. brake pedals felt as solid with the 4 as with the single.

then this year when I switched to the 6 piston brembo setup.... same thing. solid. no mush, no extended travel.

i'd opt its in the bleed job.

[scooter k]

Still has air in it would be my guess.

[outobie]

Had them bleed it again and now it feels correct
It’d be nice if the mechanics would just say “sorry” and fix it instead of making up bs excuses “it feels fine to me”

Well if THAT feels fine to you then your 30 years experience you told me about 3 times in our five minute conversation was a complete waste of your time

[HyperBlue16]

I think there are 2 models of brake master cylinders & boosters for stock RS & SS, atleast from the part numbers i saw. Guessing to make up for the extra fluid requirements of the calipers.

[PolynesianPowerhouse]

Originally Posted by HyperBlue16

I think there are 2 models of brake master cylinders & boosters for stock RS & SS, atleast from the part numbers i saw. Guessing to make up for the extra fluid requirements of the calipers.

I dunno about that.... the 5th gens when you had a v6, and went to 6 piston calipers, you also had to change the master cylinder. that was outlined in the instructions to change it.

the 6th gens, if you have the v6, and want the 6 pistons, you just buy em, no need to change the master cylinder, nor does it come in the kit.

I've swapped from the singles to the 4's and now the 6's and never had an issue with lacking of fluid.

[cdb95z28]

If they didn't do the ABS procedure when they bled, either take it back to them to to that or go out and repeatedly engage your ABS then rebleed it yourself. A Motive Power Bleeder works best.