i always get vibrations in the car while braking, it always feels worst when i brake from 30mph or faster. what can i do to get rid of this problem

 

New rotors and pads.

Then, make certain the lugnuts are always properly torqued with a torque wrench.

If you trust shops to do this for you, they will very often overtorque them and lie about it, then the extra stress in the rotor contributes to it warping when it gets hot. They'll say it's done properly, but the guy at the counter doesn't see what happened in the garage. I don't trust anyone to do this. A bonus is that if you need to change a flat with the stock tools you will actually be able to get the nuts off.

Dave

 

It's easier to take off overtorqued nuts?

 

No way. Overtorqued nuts will do one of two things: be a bi**h to remove, or stretch the stud and work loose. WIth the little wrench in the car kit, it takes a little umph to loosen them even when they are torqued properly. Its when you have an overtorqued nut when you see people jumping on the wrench or bending it to try and get them loose.

Tire/Jiffy shops are notorious for just bangin them on with an impact wrench, and assuming that if they are tight that's sufficient. The truth is that an impact wrench gives very poor control of final torque, and even if they have it adjusted the amount of torque differs depending on the stud. What works on a dually truck is probably bad for a car. For most cars, 80ft-lb is a good number. I own a cheap 10-100ft-lb torque wrench ($20 from harbor freight) and I retorque all lug nuts after a shop has had it. You'll be able to feel if they back off with more torque than when you properly torque them on.

 

I know this is kind of elementary, but it should be pointed out. When installing a wheel onto the hub, the lugnuts should be tightened a little at a time and always in a star pattern (that is, every other lugnut as you go around a 5 bolt pattern). That helps to ensure that the wheel is tighened in a balanced, uniform manner.

However, if you're experiencing this only during braking, then I'd suspect your rotors are warped, as said above. This is caused by the rotors getting too hot and subsequently deforming under load. If they get really bad, then replace them.

 

Cant the vibration also be because of a needed alignment?
what is the rule when you tighten your wheels on your own?

 

There is a million and one reasons why you would feel vibration in your steering wheels its trouble shooting that will fix this gotta start buy checking down the list of general things really

1.Tire Balance
2.Check tires
3.Check Rims
4.Wheel Alignment


to start

 

And that's a good order to work with. Alignment GENERALLY does not contribute to vibration issues. More often, a balancing weight falls off and the wheel becomes out of balance. Balancing tends to cause vibration at a particular speed, and if you rotate the wheels you should feel the effect move with it.

Dave

 

Your rotors are warped.

 

Replace brake pads and rotors....And alignment...

 

Not neccesarily! I had the same problem, got new rotors & the vibration was still there. After 135K my stock calipers had seen better days so I opted to get new calipers, what the hell 300ZX BBK was not too expensive so I went that route & after installing the 300ZX calipers the vibration was finally gone!
My girlfriends 2k1 has the same problem & my conclusion is the OEM Maxima calipers suck!(4th,5th Gen) Your problem may not be the same but if you have over 100K its a good chance that getting new rotors will not fix your problem. Be sure to have good alignment along w/properly torqued lugs as stated earlier!