Hello,


My car is a French G37 Convertible from 2010 with AT.

For years, I have had issues with that high hissing noise when I brake a little bit, but only at very low speeds. It only happens when I barely press the brake pedal, like when slowly moving in trafic jams or when I am parking (both in reverse and regular modes). That ear-breaking noise is gone as soon as I press the pedal a bit further down or when I slow down at driving speeds.

The problem seems to be more severe when the car is dirty (due to braking dust ?) but it remains there even after a deep cleaning and washing of the wheels.

The garage that maintains my car has tried several different brake pad brands : TRW (GDB), Bosch and now Nipparts. Brake discs have also been replaced with new ones from Nipparts as well. The problem is still here. It only vanishes for like a month or two when the pads are replaced.

I daily drive this car (not every day to be accurate), but I am not driving it like a pilot or whatever else, I don't have an "aggressive" way of driving at all.

The fact that this car is a convertible makes it even worse because, obviously, I hear the noise a lot more when the roof is down.

What can I do ? Is it a known issue ? Which brake pads / discs are you guys using ? Could the problem come from somewhere else ?

Please help me.


Thanks in advance


P. S. : I initially posted this call for help in the G37 Convertible section, but nobody has replied since then, hence this message here.

 

This is a fairly common issue (especially if you are a mostly "city driver") and the reason for the noise will surprise you:
Basically, the squeaking is from the rotors accumulating a light layer of dust and dirt buildup. Where the rotor and pads meet, as the rotors turn, light brake pressure allows the pads some "free play" to vibrate lightly against the rotors. This resonance is that noise you hear. Whereas under harder brake pressure, this "free play" is mostly eliminated and the noise disappears.

Usually, a light sanding of the rotor face to remove that glaze will temporarily eliminate the noise. Or, perform a few hard braking sequences (aka, bedding brake pads) to heat the brakes up and clean the rotors that way, temporarily. I say temporarily, as your driving habits classify you as a a light braker, the glaze will return. And so will that noise.

Now, this does not take into account the quality and condition of your brake pads, rotors, shims, pins, grease, etc. There are a number of factors in play. The main key here is to NOT BABY YOUR BRAKES! You can be a conservative driver, but every once in a while you must let the car stretch her legs. As much as these engines were designed to rev, these brakes are designed to stop. Believe me, you and your car will appreciate it.

Going forward, clean off your rotors either by performing the brake pad bedding procedure (aka "Italian Brake Job" as one of our moderators call it) or by lightly sanding the rotors. From there, every once in a while, take a ride out to the country, drop the top, and get a little aggressive.

Hope some of this helps, mon ami...

 

Well, yes, this helps a lot. Thank you for your quick and detailed reply, my friend

First of all, I guess I did not use the correct term : I did not know of the word "rotor" and used "disc" instead. Hopefully I understood correctly. TIL !

Secondly, is this really a "normal" issue or is it a flaw of the car ? I have owned several different models and it is the first one that I see with such an issue. The garage has another client who owns a 370Z and it is the only car he knows of with that same issue, so it appears to be specific to Nissan, or maybe to the 370Z / G37 "family" ?

Thirdly, would you still be able to recommend quality brake pads and rotors ? Is Nipparts a reliable brand, which ones would you suggest alternatively, to reduce ( / eliminate ?) the issue ?

Fourthly, am I really supposed to do a hard braking sequence in reverse mode as well ? It sounds quite dangerous to do so (I'll take the remedy with no alternative and I'm already grateful that it exists !).

Thank you once again !

 

Rotor. Disc. They are one and the same.

I would not say it is specific to any one make or model. I have seen many cars with this issue over the years. My mothers Audi A6 was horrible with this issue- but she drove like a snail to begin with while my grandmother, back in her day, drove like a bat out of hell and never had any issues with her Fiat. In my opinion, a lot of it has to do with location (city/rural) and driving style. Other people will have other opinions based on their experiences.

As for rotor (disc) and pad combinations, that topic is very debatable and of which there is no one, perfect, answer. Me, I am currently using Hawk HPS 5.0 pads paired with DBA 4000 D/S rotors (installed 4/2017 w/less than 8K miles currently). For my driving style that combination is overkill, but they perform when needed and I have had zero issues thus far. Again, other users, different combinations, different opinions and results. For most, OEM parts are fine. In the end you will have to research and decide accordingly.

Hard braking/pad bedding procedures are FORWARD only- NEVER in reverse. It is best to find a good stretch with little to no traffic. Here is from the factory manual:

I would not advise you to do anything you are not comfortable doing. If the above makes you uneasy, your mechanic should be able to help.

 

I also get this high pitched squealing noise, but it's on the right front brake with no pedal pressure at all, then its on the left side as I lightly apply the brakes like Kaighal. I'm going to be doing the bedding procedure in the next couple days, got myself a flat road I can really run them on. After not finding the name brand used on my receipt, I'm guessing they were Hawk drilled/slotted rotors and heat treated pads. I only have these on the front, haven't done the rears since I bought the car.

 

Well, I am glad to hear that I drive like a snail . To be honest, I thought that I was using the brake pads too much when the sound started appearing, so I tried to be as gentle as possible with them... Which ended up being counter-productive, apparently !

I'm writing down the names of your pads and rotors for the next replacement, thank you

I followed your advice / instructions on Monday night and yesterday, breaking as hard as possible from about 60 mph (90 km/h) to 0 on a long, empty road. I did that several times in a row and... It worked !

At first, I still had a noise, but it was not the same, it was not as loud and the "note" was different. Eventually, it disappeared. I cannot express how great it felt to hear absolutely nothing. Thank you so much (and you were right, hard breaking felt good too, I knew that this car was reliable but I am impressed by its stability and efficiency !)

The thing is, that was "only" when going forward. When parking in reverse mode at the end, the atrocious sound was still there . Not as much, but it is still very noticeable.

My understanding is that breaking as you suggested puts all of the weight of the car on the front wheels, so the rear brakes are probably not receiving enough "pressure".

Do you have any idea how to fix that ? I agree that doing such a hard-breaking run in reverse mode would be very dangerous. Should I do more hard-breaking "sessions", maybe from an even higher speed ? I can go on a nearby highway at night, eventually, but I don't know if it would change anything.

 

I am glad you are getting positive results. I would not focus too much on the weight distribution between the front and rear brakes. Yes, the front brakes do most of the work, but these cars are pretty well balanced (not quite 50/50 but darn close) and the rears have a lot of weight on them as well (especially being you have a 'vert) and can get just as hot.

During this procedure, NEVER bring the car to a full stop. You must allow a brief window of time for the brakes to cool. Here is what I usually do (might be overkill, but I'm "old school" and this always worked for me:

1) drive at 45mph, brake hard to ≈20mph (not too hard as you don't want ABS to kick in);
2) return to 45mph, repeat;
3) return to 45mph, repeat;
4) drive to 60mph, brake hard to ≈25-30mph;
5) drive to 60mph, repeat.
6) **drive normally for about 10-15min. to allow brakes to cool.
By this time you should smell some brake fumes- perfectly normal.

 

Clean pad backing of dust and apply coat of copper grease