I drive a 2003 Enthusiast with the non-Brembo stock system. I went out on a several-hour drive up in the mountains today. I was at speeds from 65 – 120. Everything was going fine. Then, about three hours into this “spirited driving,” I was coming down a large downgrade at a high rate of speed. I braked hard to dump speed and I thought I heard a low rumble from the passenger side of the car. It got worse and started to become a shudder (wobble) that I could feel when I braked.

It did not happen at all unless I applied the brakes. I freaked out and slowed way down. At the next available spot, I pulled off the road. As soon as the car came to a stop, I could smell burnt brakes.

I put it into reverse and sped up to about 15 MPH and slammed the brakes – thinking that maybe there was a bit of sand or a piece of small gravel wedged up into the caliper/rotor/pad. (Some of the roadways had sand on them for icy conditions.) I hoped that this might have removed anything like that. I pulled forward and back a few times repeating this process. Then I headed back onto the road (taking it easy).

I could still feel this shudder and hear a low rumble sound every time I hit the brakes for a while. But after about 20 minutes, it seemed to get better and better. I drove all the way home, which took about another 1.5 hours. By the time I got home, the shudder was mostly gone – but still there a tiny bit. And now the brakes squeak at very low speed stops. They never squeaked before.

Tomorrow morning, I plan on removing all four wheels and inspecting the calipers, rotors, and pads. It seems like if I “fix” what went wrong, then I’ll only bring my brake system back to where it was before – which means that this problem may happen again in future “spirited driving.” I did a search on the forums and found a few related threads. But I still have questions:

#1 – My understanding (from what I’ve read here) is that I got my stock brakes too hot and this may have boiled my brake fluid and caused my pads to deposit material onto the rotor, which caused the shudder and rumble. And if that’s true, I need to immediately replace my brake fluid and somehow remove the material from the rotors. Does that sound right?

#2 – I know that to continue to push the car like I’ve been, I have to upgrade the fronts. But are the rear brakes really that necessary? Are rear upgrades more necessary on the 350Z than other cars?

#3 – I’ve been looking at the Stoptech kits. Will their 332x32mm rotor with the ST-40 caliper fit under the stock 17 inch rims?

#4 - If I do upgrade the rears too, why should I pay $4290 for the front kit mentioned above plus the smaller 328x28mm rear rotor and caliper, when I could just pick up two “front” kits for $1995 each. Two of those front kits would be $3990. That’s $300 less than the total package with the smaller rear equipment. Will the “front” kit fit the rear wheels? If it does fit, why does it cost more for the smaller caliper and rotor?

Thanks for the help!!

 

Front kits are not meant for rear use.

 

It could be possible that you warped your rotor from the excessive heat or worse case cracked it. The warp will cause pulsing in the pedal. I know for a fact in older cars without ABS. I am not sure with ABS. I have heard of some taking their cars to the track with stock non brembos and not having any problems. I never tracked mine to really see how much abuse these brakes can take.

The brake fluid boiling I have heard of but not casing the rotors to deposit material. Boiling fluid causes gases to form in the lines, causing a spongy pedal.

The purpose of a Big Brake Kit is to dissipate heat better then the stock systems. It will depend on your driving if you think you need better brakes in the rear. It won’t hurt and it will give you that added safety coming down the hill you were on. Instead of using the Stoptech rears, look for different brands. The combo sold by Stoptech was designed to be used with the stock master cylinder. Changing out the combo with larger rear calipers along with the large front calipers may warrant you to get a larger capacity master cylinder not to hold more but designed to move more brake fluid.


Let us know what you find.
Monsta

 

When you buy one of these brake kits you buy the results of many hours of design and testing. The most important thing you buy with a StopTech kit is their expertise and years of experience, why mess with that? If you the have time and money to design and test you own brake system you may be able to get better results at a lower cost, but I doubt it.

These brake kits are expensive but, as with most things, you get what you pay for. I'm very happy with mine, StopTech makes outstanding brakes that will stop you without complaint all day long.

 

Sale is pending on my BBK that I have for sale, but some FYI

 

i agree with what was said. if you got them hot enough, you might have cracked a rotor.
i have boiled brake fluid before and all it did was cause very spongy brakes (kind of how your brakes feel after replacing them, but didn't bleed them enough). go get a better brake fluid and flush out the system, that should take care of that.

in regards to running brakes on the rear that are meant for the front, don't do it. front brakes are typically much stronger than the rears, because that is where the majority of the force is needed. i suppose you could do it, but you will spend more time and money on getting a bias control kit and figuring out the correct settings. on my black two, i have a big brake kit, but also a bias control kit, i have spent many days and hours trying to find the optimum setting (depends on the track, temperature, and a bunch of other factors). overall, it is best to get both front and rear. yes i costs a little more, but the benefit in performance is well worth it.

 

Check the brake specific forum, there are questions very similar to this.

Reference:
http://www.stoptech.com/whitepapers/...tter120601.htm

http://www.stoptech.com/whitepapers/...erformance.htm

http://www.zeckhausen.com/Testing_Brakes.htm

 

I just spent a few hours inspecting and cleaning all four brakes. Everything looked OK - no cracks, no warping (that I could see). There was a lot more dust on the inner pads, both on the fronts and rears. I knocked the dust off the pads and cleaned everything up.

I put everything back together and took it for a short drive. THe brakes are stopping the car just fine, but I swear I still feel a low rumble that wasn't there before.

Take a look a these pics. The first two are the dust build-up on the inner front pad.

 

#2

 

Here you can see a dark line that was on both rear calipers. I never saw it there before - and I just spent some quality time with the rotors a few weeks ago painting the calipers.

 

you really heated them up, they look like they turned bronze colored. That dark line is proably excess pad material. Thats proably whats causing your rumble. Not a safety issue just a comfort issue. I have heard that you can take a high grit sand paper to the rotors and rub off a layer of pad material but you need to rebed the pads( only something I have heard somewhere)