jman7777

So I'm not the lightest guy aound, bout 240ish. I picked my friend up (he's about my weight) and we went for a drive. Now, when I go to apply the brake, we'll... i need a lot of force to stop the car. Even more so when i have passengers in the back as well. It's feels unsafe because my stopping power is almost nonexistant when i have a car full of people. My brakes were checked within the last year or so I believe, i need to find my slips to be sure. It brakes fine when i'm alone in the car, yet when i have a buddy and or passengers in the back, I really need to mash the pedal to stopl. Is this normal, do i need new pads? what's the deal? I do not have abs btw.

97Se5spd

I would think it could be the pads most likely. But it could be other things like air in the lines or something.

MaximaEvolution

iTrader: (2)

check ur rotors... after a while they get I think whats called "heat glaze." I may be makin that up so dont quote me but, after so many times of heatin up they get "glazed" and the pads wont grip as well.

New pads and new rotors would deffinetely do the trick. Otherwise get ur rotors cut, it'll remove a few layers off the rotor.

My 3 cents

wannaboostbad

that "glazing" can be solved 2 ways (i saw this at lexus a few years back)
1) cut ur rotors, get new pads (if worn out) if not sand the SIHT of the old ones if u have enough meat on them should solve it.
2) go to a closed off street with enough road infront of u, and no traffic, get up to 45-50 and then basically lay heavy on the brakes BEFORE ABS kicks or u lock them up that should remove the glazing........(again saw a guy do that on a 2001 ES300 with roughly i think.............45K)

jman7777

would replacing the rotors be better than cutting them, or would it not matter? also what if i purchased brembo slotted/drilled rotors, yet kept the same stock calipers and pads... I probably wouldn't see much better stopping power, correct?

RockfordMax

iTrader: (2)

yep. slotted rotors would cool better, making the glazing harder to do in the future (the pads glaze over btw, not the rotors). Either way, sand the pads if theres more than 50% left, otherwise just get new ones anyway, theyll start to squeak soon.

njmodi

iTrader: (4)

The extra weight will definitely contribute to poorer braking performance. Think abuot, if you have 3 others in the car with you, say average (low end) of 150 lbs each, thats another 450lbs of weight... that's more inertia the brakes are working against.

dgeesaman

iTrader: (10)

Replacing is better, but I'm not sure that is your problem. If you choose to replace them, the most durable rotors are Brembo blanks. Slots and drilled holes just add cost and no benefit.

You should have no trouble chirping your brakes to a stop from, say, 15 or 20mph. The weight of you or your friends is relatively unimportant - a 3100lb car with 900lb of people isn't *that* much different than a 3100lb car with 240lb of people.

I suspect you need to bleed your brakes out completely. 1 Qt of fluid is only $7 and should be enough to totally flush the system.

Dave

jman7777

I realize that. however lately it seems to be getting worse and worse. had the pads changed 23k mi ago back in 2003, they should still be good. but we'll see. Thank you for all the replies

MaximaEvolution

iTrader: (2)

#1 - The blanks may be the most durable, but as far as performance/endurance, the crossdrilled will give you the best cooling. If you've ever raced around for a few hours you WILL notice the difference. When cold, crossdrilled rotors will give almost no better performance.. The gain in brakin power comes when they are hot, there is little to no fade.

Slots are not quite as good, but better than the blanks for performance. Also with the slots you won't have to worry about the pads glazin over cause they will eat your pads like pacman.

#2 - You nuts bro? think about what you said. You add 900lbs to a 3100lb car you're increasin the weight by about 30%. 30% !! Thats a LOT of weight and you WILL tell the difference IMMEDIATELY.



You alone compared to you with 3 of your friends will put an immense amount of stress on your brakes.

dgeesaman

iTrader: (10)

I don't think you know what brake fade is. It does not appear in a few hours, and it is very hard to produce on the street, no matter how ricer-boy you drive. It happens on a track, in a matter of minutes, when braking hard, repeatedly, and the whole wheel/hub/caliper gets so hot that the the brake fluid boils or the brake pad begins decomposing and deposits a layer of crud on the rotor. The only time this could happen on the street is if the brake fluid is badly saturated with water, and suddenly starts to fade at an unusually low temperature. That is why I suggested bleeding the brakes.

It's been demonstrated that drilled holes and/or slots in cast iron rotors do not improve performance with modern street brake pads, either in terms of friction or thermal performance. The days of a 'gas layer' building between the rotor and pad that needs to be vented are decades gone. Thermally, the holes are simply less material to absorb and dissipate the heat generated by the braking event.

Change in apparent friction is not a function of the rotor. It's the pads. In street pads, what you say is actually not true - if you get street pads appreciably hot (again, not possible doing street ricer runs), they won't brake worth a damn because they're disintegrating.

Yes, and it will require 30% more clamping force in the caliper, which is 30% more pedal pressure. But it cannot produce "my stopping power is almost nonexistant". It will not overwhelm any stock braking system, and so it suggests that the brake system has something wrong.

Of course, there is the possibility that the OP is really just a very unaware driver and fails to adjust for a heavier vehicle. If you tailgate and try to stop hard, just 20' of additional stopping distance will feel like a huge difference. If your habits lead you to not apply 30% more pedal pressure, and you casually try to stop at a red light from 60mph, you'll **** your pants when you finally realize you're going to end up in traffic. If you don't know anything about braking and vehicle weight, you might not realize you need to do more stopping, sooner. I hope the OP really thinks hard if this is the true reason.

30% is immense?

Dave

Black Maxima

The 4th Gen braking system sucks ballz...

MaximaEvolution

iTrader: (2)

I do know what brake fade is. And with my pads/blanks I've experinced it quite often on the street. Although I cannot argue with you in such detail because my knowledge of it doesn't extend that far. However, I know what it is and i know that it sucks.


The demonstration you speak of is with BBK's. Due to the increased rotational mass, they do not give a huge increase in functionality on street cars.

ok heres a good example IMO...

Let's say you weigh 200 lbs. comfortable/athletic...

add on another 60lbs (30%) and try to run around the block. Then try tellin me that it wont make *that* much of a difference

clive

"My brakes were checked within the last year or so I believe, i need to find my slips to be sure."
"within the last year OR SO"?? "I believe"?? WTF!!!
I hope you're not driving behind me... Get the damn vehicle up on the jack right now and check the freakin' pads! You're probably braking with the metal backing plate! I use just stock semi-metallic and I can easily get the ABS working on a dry road with 4 passengers if I want to. Your brakes must be toast!

dgeesaman

iTrader: (10)

You both may have had degraded braking for any number of reasons, most of which involve inferior parts (e.g. pads), or insufficient maintenance (e.g. water-saturated brake fluid). But the answer is not a change of rotor. It's better pads or new fluid. Fluid is cheap, easy, and good for the long-term life of the braking system, so I suggest starting there first.

Oh really? So know you know my sources? LOL, it's nothing to do with anything BBK. On the street, if you're getting off-gassing, it's because you're abusing your pads and/or the pads are even crappier than the regular OEM pad. The answer is not a slotted rotor - it's more adherent pads.

It's ironic that you're trying to explain to me what 30% means, and I'm a mechanical engineer by day. I could easily throw in more math, but I think that would only confuse things further.

I will make one last try to explain my points.

The OP described losing nearly all ability to brake. There are two possibilities:

1) He is accurate in his assessment "that my stopping power is almost nonexistant". Unless you're accustomed to braking right below the limit of locking your wheels, the brake system should have much more than 30% braking force available in reserve. He should able to lock his wheels and slide no matter how much weight you add to the car. The only way that adding 30% weight to the car would cause the braking system to lose stopping ability is if it causes the brakes to no longer work properly.

If there really is a mechanical issue where the extra braking force causes the braking system to not reach maximum clamping pressure, it's most likely to be water absorption in the brake fluid or really cheap brake pads (generics or Nissan Key Value). The right pad and fresh fluid will be more than adequate for any street application, even with blank rotors. I suggest a 'high performance street' pad, or the good OEM Nissan pads (not the Key Value Nissan pads), and a full 4-corner flush with 1 qt of DOT 4 fluid.

2) The OP is not well-versed in how to compensate for additional stopping distance and doesn't notice until the last moment that their normal braking habits are going to leave them stopped way past the red light. Getting close to the last moment, the driver realizes they need to stop faster, and they mash the brake pedal abruptly and skid to a stop. This driver leaves thinking their brakes aren't working properly, when the real problem is that when stopping at high speed, you need to brake earlier and more. The mental image how much stopping distance you need becomes mistaken for braking system problems.

Since your points sound a lot like the little blurbs I see in the product descriptions of brake rotors (a collection of half-lies biased to sell the product), I suggest you upgrade your information and visit www.stoptech.com and read Carroll Smith's technical articles. These guys (Carroll Smith) are well-heeled, although you will need to pay attention to which things apply to track driving vs. street driving.

Dave

jman7777

before you make an @sshole remark, make sure to read the entire thread. I had posted that the pads were replaced 23k mi ago, basically meaning they should[ still be good. I wouldn't be braking at all and there would be a horrible noise if i was braking with the metal backing plate, use your head on that one. I also DO NOT have abs, so dont bring it up. I appreciate all who used their brains and provided me with great feedback on my original question, and will take into serious consideration your advice.

clive

23,000 miles? Depends. Some pads don't last 10,000. It's not rocket science, just jack it up and remove the wheels and check. Before driving it any more... for all you know, one of the brake hoses is bulging, or the caliper piston is leaking, or you indeed have no pad material left, perhaps on one side only because of stuck caliper pins, or the brake fluid, being hygroscopic, is mainly water, and once finished, is the master cylinder leaking, is the brake booster working properly...

nismos14

iTrader: (56)

If your not inclined to do it yourself, have someone check the brakes again, if nothings wrong, time for some 18's and a BBK

vsamoylov

hondas is worse

Intel

iTrader: (2)

Well having had my car fully loaded with camping gear and 5 friends I can say that it stopped just fine but I had porterfield brake pads and had just fixed everything up. I would definately get your brakes checked out quick as it shouldn't be a problem with that much weight. Hopefully it just needs to be rebled but for all you know the rears are complete jammed up open and aren't moving like mine were.

darklegend06

iTrader: (11)

I just recommend bleeding the brakes like the other has suggested.

jrbeilke

iTrader: (1)

Definitely get those pads checked out and don't forget to get some new brake fluid! Depending on climate, driving style, and other factors brake fluid should be flushed around every 12K miles for peak performance. Otherwise you will end up with water in your brake fluid which can lead to poor braking performance and possibly corrosion or a seized caliper, especially the max rears.

MorpheusZero

iTrader: (10)

I just realized that I have the exact same problem with my roomate in the car (~260lbs). Brake feel is drastically affected and I need to mash the pedal in order to get any significant braking. My brakes are bone stock, so obviously they never really had much bite to them, but increasing my car's total weight by far less than 10% makes even normal driving for me feel dangerous. And no, I don't normally drive like a maniac. But whenever I'm coming to a stop (especially downhill) I have to start braking much earlier and harder with an extra 260lbs than regular. This is very very strange. Has anyone else had the same experience? I had front calipers/pads replaced 10k miles ago.
Oh, and I DO have ABS... but it seems that doesn't make a difference.

Again, to reiterate, my braking is fine normally. But the extra 260lbs feels like it REALLY cripples my brakes.

dgeesaman

iTrader: (10)

Definitely bleed your brakes.