Hello all, I am reaching out for some wisdom and advice. My 2011 G37x Sedan is having some issues with its brakes. When I first got the car a few months ago, I noticed there was some pulsation when braking from highway speeds so I got new pads and rotors since the previous owner had no idea when the last time he got new brakes. Rotors and pads went on and that solved the issue, but when I was changing them I noticed there was some play/wiggle in the calipers. I'm pretty sure that's not supposed to happen, but coming from a coupe, everything in the sedan is softer and more comfortable so I shook that off as a comfort thing with the brakes. I should have known better. Now just a couple months later the brand new brakes are pulsing again...

If I need to get new calipers and the flexible hoses that go from the brake lines to the calipers, is there any way to do a cheap upgrade? Like could I get used 370Z calipers and put them on my G sedan?

Hopefully some of you have some experience in this sector. Thank you all in advance!

 

Floating calipers will always have play. The caliper slides on the pins in order to clamp the brakes.

Brake pulsation is caused by pads that overheat and smear themselves on the rotor. Usually the actual genuine factory pads from a dealer are sufficient. If you do go aftermarket, you should pay a lot of attention to what type of pads you choose. Its not trivial or simple to do this. Just choosing the "better" pads at a parts store isn't wise.

The best simple brake upgrade involves proper brake pad choice.

And...maybe a set of braided lines for a much smaller effect on street driven cars. Braided lines should be periodically inspected and replaced, however. You can't quite take them for granted like a genuine factory part.

Hopefully someone else has info on choosing caliper/rotor combos that increase brake torque through over-sizing. Usually, though, doing this properly requires upgrading of the master cylinder, booster, and ABS block/programming.

 

I was inbetween getting braided or OEM brake hoses. Also I got PowerStop pads, and to my knowledge they're one of the best for daily driven cars... So when I get new calipers and hoses, I could just get my existing rotors turned down a few thou to get them smoothed out? Cause I got drilled and slotted rotors as well so I'd hate to have to buy them again.

 

If your rotors are pulsing...cutting them may or may not resolve the issue.

Basically, the theory as I understand is like this:
The previously overheated spot may or may not have cause martensitic hardening to that spot on the rotor. If it did...then that spot on the rotor will be harder than the rest. Even after resurfacing...it will wear slower through use, and eventually become higher than the rest of the rotor...and your pulsing will return.

Ceramic pads also depend on adhesion bonding for friction. So you usually need to bed in a transfer layer for the pad to ride on. So make sure you bed them in if you do resurface the rotor. This will help with pulsation and wear.

Drilled rotors will theoretically run HOTTER than blank ones since you're reducing surface area. Performance brake systems with factory drilled rotors have the drilling done to reduce WEIGHT...not heat. And the pad/rotor composition is specially chosen to deal with that.

Slotted rotors do theoretically cool the surface. But...idk if its effective.

Brakes are complicated.

I usually choose a good set of semi-metallic pads and blank rotors. This results in good, smooth braking...but a lot of dust. So to prevent the appearance of brake dust...I just avoid looking at my wheels.

 

Well that's unfortunate. I got the drilled and slotted rotors thinking that would help prevent them from getting too hot, plus they look really good. I also got ceramic pads to keep the dust down, and I did the break in procedure they put on the box. Didn't feel like it made a difference, but maybe it was for that adhesion bonding thing you were talking about. So basically I did everything that I shouldn't have done..... lol

 

Lol. I wouldn't worry too much about it.

Lots of people do these simple modifications without issue. The only reason I posted by buzz-kill info is to give you a potential root cause and future prevention.

If they were not pulsing currently, you could have just ignored everything I said and enjoyed your new brakes!

You can always try resurfacing them to see what happens. With ceramic pads, just avoid clamping the brakes after a hard stop. I realise this is hard to do with an automatic car, though. I'm guessing the pulsing started again after a hard highway stop or something.

 

They are pulsing and progressively getting worse. I do remember when I was installing the new pads and rotors that one caliper's pistons were much harder to compress. So I have a feeling the hose on that side is splitting and locking up the caliper. I had the same issue when I had my coupe before this sedan. I'm going to try getting new hoses and see what that does. If the pulsing lessens or goes away, I know that was the issue. I'm just worried the rotors might be too far gone to salvage.

 

Pistons being hard to push back could just be from internal corrosion. Brake fluid attracts water, and should be changed every 1 to 2 years.

It may take a new caliper.

Are your calipers properly sliding on the pins? And are the pads properly sliding on the hardware? Sometimes, aftermarket pads need to have the ears shaved and other times, rust can build up on the ears or under the hardware.

Ears should be lubed with moly paste or similar. Slides need silicone paste.

 

Dangit. Maintenance records show brake fluid was changed shortly before I got the car this summer, so I'm good there. Is there any harm in getting used calipers? Rock auto has re-manufactured PowerStop calipers for about $80 for the front pair after the core refund. This is where my cheap upgrade question comes in, cause I'd love to put on the Akebono calipers if they are compatible. They look SOOOOO much better than these normal calipers and each side has independent pistons, to my knowledge.

 

I don't think used calipers will be an issue as long as they're in good shape.

This may be obvious...but the Akebonos will require the matching rotors and pads to go with them at the least.

Someone more knowledgeable on these cars will have to advise whether the Akebonos even bolt onto the normal spindles and if they require a master cylinder, booster, ABS block, e-brake, or other changes.

Also, not sure if the Akebonos fit under the stock non-sport wheels.

 

Yeah, I was wondering if all those factors were worth the trouble. I'm probably just going to play it safe and just paint the normal calipers I get so they look better. Well it looks like I'm just going to have to get all new calipers and hoses, and probably rotors and pads too...

 

Good luck buddy.

Be careful with those hoses. I'd recommend getting that particular part from Nissan/Infinti direct.

 

If you have the sport wheels, I'd do the BBK instead.
It's only slightly more expensive than replacing your current kit. https://www.myg37.com/forums/brakes-...the-cheap.html
If you opt to keep your brake lines, you'll just need new Banjo Bolts. You'll need to also bend or cut your brake dust shields. Everything else bolts right on up, plug n play.
I also think that these solid calipers are much easier to maintain than the floating ones in my BMW (essentially the same as the non-sport G).
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What you maybe experiencing is fade from the combination of the cheap slotted + ceramic pads. Ceramic pads are sold with the "no more brake dust" backing behind them and has people under the impression that performance is the same and it is not.
Ceramic pads just dont brake as good as "metallics" and at this point is basics. Metal will stop better than ceramic. Metal does create quite a bit of dust and is the reason most go for them, it introduces longer stopping times in exchange for less dust.

One of the reasons why your new rotors maybe pulsating so quickly could be due to that hard caliper. It maybe old and rusty inside causing it not to let go when it needs to staying engaged more over heating over time warping the rotor.

Beware Used is not the same as Remanufactured. Remanufactured calipers are old units that have been rebuilt basically being 90% new. Used is an OEM unit that is still using oem 10 yr components
Buying a used caliper when you dont know if the calipers are your problem can be money down the drain. Now that you have those "newer" brakes re check your calipers and gauge the piston movement. If this is in fact the case you should see the pads lower on that side also.

 

I'm pretty sure the OEM rubber lines are the problem. I had the inner lining split on me when I had my coupe and it was locking the caliper onto the rotor and I think that's what's happening now with my sedan, it's just not that bad yet.
I've done some research and I think I'll be able to salvage my pads and rotors, and I'm just going to go one by one starting with the hoses. If it comes back, then I'll replace the calipers. At that point, I'll see if the Akebonos are available. From what I've seen they're scarce and expensive lol even the used/remanufactured ones. I would agree that the solid build of the sport brakes would make them a little easier to maintain since the only moving parts are the pistons.