Hi I am new to the forums. i have a 2003 350z. after a couple of months owning the car when i slammed my brakes it was a strange vibrating feeling on the pedal felt like a grinding metal very very strange and the brakes would not lock up and stop. Took it to the shop and was told i needed new rotors and pads. had everything changed and brakes didnt not vibrate anymore at high speeds but still when i slam them i feel that strange vibrating of the pedal and no luck up, no screeching tires and know dead stop. happend to me this morning on the way to work. feels like the brake pads arent crabing the disks hard enough very strange cant really describe. Any one else had these issues. i hate to be in a dangerous situation that i need to slam my brakes and wont be able to stop. sorry if some of the thing i said dont make sense or are wrong not to familar with these type of things. all input and help would be apreciated on whats casing this and what i need to do to have it fixed.

thanks

 

forgot to mention when im casually stoping and breaking the breaks feel strong but when i push them a little to hard it happens.

 

any1? did i post in the wrong section? helllppppppppp

 

I suspect you are just feeling the anti lock system operating. You should not be able to lock up your wheels and make them skid. You do know your car is equipped with an anti lock braking system, I hope.

 

I know i have ABS and i know what it feels like that doesn't feel like abs. feels more like the brakes are letting go. its hard to explain. when anti lock kicks in from what i know there is light screeching (on and off) from what i know correct me if im wrong. mine just makes a metal noise. is that a better description?

 

You could check a few things. If you got new pads and rotors and they were bedded in correctly you should not feel any pulsation through the brakes. You could have some loose suspension bushings or tire feathering. I've seen tire feathering or cupping of the tires yield some pulsing through the brakes. When you are light on the brakes you may not compress the tires enough for you to feel this through the brake pedal. Panic level braking can cause you to feel more of the tire irregularities. So, check the inner and outer edge of the tires and see if you can feel the tread blocks alternating at different heights. Also, do you get a tire "roar" at any speeds?

The other thought is you might have some worn suspension bushings that may cause some vibrations under hard braking....

Lastly, I've seen bad "new" parts before too. Some of the rotors out there aren't great and even new you might feel some pulsations.

Hope this helps.

 

I'd also check for air in the brake lines. Can you bleed them yourself? Try flushing the lines and using a good quality brake fluid. Also, if you "hit" your brakes hard when they're new, you can glaze the pads, but this is easy to check for. Do the work yourself and you'll figure it out.

 

thanks but my tires are new maybe 5k on the. they are balanced and everything. not sure about my suspension, never felt anything weird go on with it feels firm and through corners feels fine. i will have the bushing checked. no tire roar either

 

but the pulsation only accrues under hard braking. im not to familiar how to check if the breaks were bled or not. whats an easy way to tell? thanks again.

 

I have the same thing, dealership wants to charge me $178 to fix, gonna try to find another way. Mines not to bad but going down hill you can definitely feel it when braking.

 

Are you located in socal?? Mine is only under emergency braking. When you brake hard does it feel strange?

 

I thought I had responded but I don't see the post so just in case. Yeah I'm in social. Near thousand oaks, I guess I didn't read your post fully since its an e brake issue which after reading the list of repairs the dealer gave me I had a rotor issue. They wanted to charge me $178 to machine my front two rotors, and I buy two new ones for that price. If it's an e brake issue search the web for people with similar issues or have the dealship tell you what the exact problem is, it may be a problem u can fix from home and not have to pay those overcharging....

 

i wouldn't worry about it. it's your abs. my other cars have done pretty much the same thing. it does feel and sounds like your car's falling apart though.

 

so its normal then? is my car still breaking in time? have you tried fixing this problem? please let me know

 

I recently bought an 03 Track z,

Same issue, there is no F#### way this is normal, its the kind of thing you expect to happen when you actually slam the brake down hard not when you lightly tap the brake.

It brakes fine even under moderate pressure, I can force the braking issue described above when entering a corning and pressing lightly on the brake pedal once the corner has began.


A better explanation of the problem is:

At low speed approaching a corner you tap the brake to slow down a fraction *boom* the car shudders, the brakes stop slowing you down and you feel the brake pedal tension release and start shuddering. This should not happen at such a slow speed and with little pressure applied.

Note this happens when turning, something not lining up right with the wheel/suspension/braking system maybe?????

Also have over sensitive VDC (if I let it stay on).

Brake issue happens with VDC on or off.


My car is under warranty still so will let you know what they do to fix it, shouldn't be too hard seeing as I won't be the one throwing money at it

 

I know this thread is old, but I am experiencing the same issue as OP in my 04 Roadster, braking works fine and dandy until I need to slam them in an emergency. I drive with TCS traction control OFF about 90% of the time but I don't know if this is the issue? Upon slamming the brake it starts to slow like normal but then all of the sudden tension is gone and it feels like a grinding (feeling through the pedal) and the car no longer slows at the proper rate, with any less luck I could end up rear ending or worse. Was this issue ever resolved for you guys?

 

TCS will not affect the braking under these conditions.

Are you familiar with how anti-lock works? The juddering, "grinding" feeling through the pedal under hard braking is just that, the pulsing application on/off of the brakes to avoid lock-up.

The feeling of tension disappearing is normal under ABS activation because in reality the brake pressure to the pads is cycling on/off - this is the feeling which leads to the old wives tale/misnomer that ABS brakes don't work as well as what used to be called "conventional brakes".

The key to using ABS brakes to their maximum potential is the same for any brake system, firm "squeezing" of the pedal, not stomping. In emergency situations as well, it's good to know how/when to momentarily release pressure on the pedal. By doing this, it allows the driver to never make the brakes "take set" and activating ABS.

Emergency maneuvers requiring full stop *right now* should also trigger your clutch/shifter leg/hand. Or in the case of an automatic, your hand on the shifter.

If anyone wants to chime in with what I usually say in such posts, go for it.

 

Gotcha, My last car was a 2000 Celica that apparently had ABS & well it felt nothing like this when abs engaged , makes me wonder if it even engaged at all when I had that car
I greatly appreciate your response you saved me a headache thank you.

 

Driving School

 

Find an empty parking lot and play around. You will hear the ABS pump after you stop if you actuated it and kept your foot on the pedal. Try it a few time and get used to it. Every car is different.

Posted before reading dates... why was the revived?