car vibrates when i mash brakes....help!

[chosen1]

yeah guys/gals

i drive a nissan b12 and I notice it significantly that when i am decreasing from high speeds, when i apply pressure to the brake pedal, i feel the pedal and steering vibrate quite a bit before the car comes to a stop.

what may be causing this? i am thinking that the wheels may need balancing???

[Aaron 2NR]

rotors need machining

[chosen1]

thanks guy...

[black start]

check the bolts on the brakes calipers.....

[Kongorealm]

speed balance all four tires first and tell us if the vibration stops...does it happen only at high speeds?

[bd319]

if it feels like the pedal pulsates when applying moderately to high force on the brake pedal.............machine your rotors........make sure to note your minimum diameter and overall rotor condition and decide if to machine them or just buy a new pair

[axe]

if it feels like the pedal pulsates when applying moderately to high force on the brake pedal.............machine your rotors........make sure to note your minimum diameter and overall rotor condition and decide if to machine them or just buy a new pair

X2

[roger]

thanks alot guys

i have this same problem as well...so i appreciate the responses

[*$kїđž!™]

read through this post ---it may help----


http://forums.trinituner.com/forums/vie ... p?t=296553

[sigma-turbo]

im guessing its not doing it when your just driving around and using the brakes at low speeds

More when your giving the brakes a hard time and they're getting hot yeah?

If its thats correct then it means you have a hot spot on your disc, MACHINING WONT FIX THIS, as the spot will return once the disc is hot, only way to solve it is to replace the discs


If its doing it while they're cold then you have a disc that is suffering from disc thickness variation (DTV ) this can be resolved be machining

[buzz]

^ interesting

i swapped rotors already and still have the same problem, slide pins maybe ?

i'm also curious, could this problem stem from the steering rack ? (ends, etc etc etc)

cause i don't see whats still causing my problem

[sigma-turbo]

^ interesting

i swapped rotors already and still have the same problem, slide pins maybe ?

i'm also curious, could this problem stem from the steering rack ? (ends, etc etc etc)

cause i don't see whats still causing my problem

yeah worn rack ends can cause a shake but in most cases its a constant shake

they will also have a slight knock if you turn the steering back and forth quickly assuming nothing else is worn

[bushwakka]

im guessing its not doing it when your just driving around and using the brakes at low speeds

More when your giving the brakes a hard time and they're getting hot yeah?

If its thats correct then it means you have a hot spot on your disc, MACHINING WONT FIX THIS, as the spot will return once the disc is hot, only way to solve it is to replace the discs


If its doing it while they're cold then you have a disc that is suffering from disc thickness variation (DTV ) this can be resolved be machining

i thought that the reason the problem doesn't surface when mashing at low speeds is just due to less force needed to stop and hence vibration isn't noticed

what causes a hot spot? thats just how it was manufactured? irregularity?

[V2NR 3.0]

rotors need machining

well said

[chosen1]

thanks guys will do the spped balancing first and see if it helps....

i work close to a good machine shop, so i will look at facing the rotors afterwards

[Anotrin]

warped rotors ist teh most common issue.

[sigma-turbo]

im guessing its not doing it when your just driving around and using the brakes at low speeds

More when your giving the brakes a hard time and they're getting hot yeah?

If its thats correct then it means you have a hot spot on your disc, MACHINING WONT FIX THIS, as the spot will return once the disc is hot, only way to solve it is to replace the discs


If its doing it while they're cold then you have a disc that is suffering from disc thickness variation (DTV ) this can be resolved be machining

i thought that the reason the problem doesn't surface when mashing at low speeds is just due to less force needed to stop and hence vibration isn't noticed

what causes a hot spot? thats just how it was manufactured? irregularity?

Rotors can also develop hard spots (hot spots) that contribute to pedal pulsations and variations in thickness. Hard spots may be the result of poor quality castings or from excessive heat that causes changes in the metallurgy of the rotors. A sticky caliper or dragging brake may make the rotor run hot and increase the risk of hard spots forming. Hard spots can often be seen as discolored patches on the face of the rotor. Resurfacing the rotor is only a temporary fix because the hard spot usually extends well below the surface and usually returns as a pedal pulsation within a few thousand miles. That is why most brake experts replace rotors that have developed hard spots.

plenty if info here
http://74.125.155.132/search?q=cache:7c ... clnk&gl=au