My car shakes when I start braking at high speed... What's wrong?

[AllenRPS13]

When I drive at about 80mph and i step on my brake pedal harder, my car begins to shake... so weird... really don't know why. recently i have changed the front and rear brake pads, and then the problem exists... thanks for any help or suggestion!

[vegita319]

Have u looked at ur rotors? They might be warped. Some people also find that they get alot of brake shimmy when the tension rods are worn. Check both of those two problems.

[Bone]

10 to 1 odds its Rotors.

[Silvia Wannabe]

I'll take 100 to 1 on rotors. Either have them machined or replaced. Go Drilled if you do replace them this will keep you from overheating them again.

[wootwoot]

I always thought drilling was mostly for less rotating mass and some heating benefits while vented rotors aided more in cooling. Hmph..

[Phlip]

Rotors it is

[**rOb**]

i have the same problem, hard breaking at high speed... car shakes till i reach a lower speed, didnt have a chance to look at rotors. anyone know the priec to get them machined?? thanks

-rob

[oO0OthinkO0Oo]

in my area it's about $8 per rotor. not too big of a deal.

[Bone]

yeah its like $35 or $40 for new OEM's from a parts store.

[wootwoot]

Be careful for who turns them. A lot of people will turn them to fast and they will be warped soon again.

[Bryants95240sx]

yeah its like $35 or $40 for new OEM's from a parts store.
wow, really its like 15 bucks for new rear rotors at napa here ,althoug the front might be that much i havent checked.

[vegita319]

there a link to slotted brembos for 70 bucks each. I'll look for it if ur interested. If not, I won't bother looking for u.

[ledzeppelin240]

THE ROTORS ARE NOT WARPED, ITS THICKNESS VARIATION. This has got to be the most misunderstood automotive problem. A floating caliper assembly will cancel out that but the thickness variation it will not. A solid rotor will be the best, cross-drilled and slotted are mostly for looks in my opinion. The more mass you have the better the heat can be dissipated.

[97DubTruck]

Listen to Robert Plant. Blanks are where its it.

[w1ngzer0]

THE ROTORS ARE NOT WARPED, ITS THICKNESS VARIATION. This has got to be the most misunderstood automotive problem. A floating caliper assembly will cancel out that but the thickness variation it will not. A solid rotor will be the best, cross-drilled and slotted are mostly for looks in my opinion. The more mass you have the better the heat can be dissipated.

what about if a car can't keep alignment and it shakes when you brake? could it be the tension rods then?

[ledzeppelin240]

what about if a car can't keep alignment and it shakes when you brake? could it be the tension rods then?

Yes in that case I would start checking out suspension components. The best thing you can do is get the car on a hoist and take a good look over everything, with a journeyman mechanic or knowledgeable person. You can learn a lot from the right people if you ask questions. That way maybe3 something you overlooked is caught by them.

[s14turbosilvia]

wheel bearings.

[MasterOFDrift]

drilled rotors are no good if you are in a wet climate they tend to crack after time

i just have slotted brembos that works for me.

[ledzeppelin240]

From wheel bearing runout you get a low brake pedal...

[Nismo180]

THE ROTORS ARE NOT WARPED, ITS THICKNESS VARIATION. This has got to be the most misunderstood automotive problem. A floating caliper assembly will cancel out that but the thickness variation it will not. A solid rotor will be the best, cross-drilled and slotted are mostly for looks in my opinion. The more mass you have the better the heat can be dissipated.


WOOHOOO someone else knows what they are talking about!!!

A word on slotted/etc. For the most part yes, high quality blanks(Brembo blanks will really do it for just about everything a street car will see) are the best for braking with street pads most contact area. On pads with no gas output(anything suitable for street use) slots/holes are useless.

Drill holes all these really do is increase a rotors tendency to crack, until you get into really high grade materials(See also Porsche brakes) then it's a different story.

Slotted are really the best of both worlds, still get maximized contact area, you can slap on a set of track pads and they will work great because the gasses are getting vented, and best of all they look pretty behind big useless rims :) I personally use and love Powerslots and Hawk HPS pads on my daily driven auto-X car and for the occasional lapping days I just swap on teh HP+ good times are had by all.

If you want to know alot more about brakes go to the Brembo website and read the FAQ wait till you get to the part about warped rotors woo would have thought the pads were depositing uneven?

[XxJaPxOxNeEs23xX]

i think its alignment. check your tie rods and tension rods. check if its out of alignment and then also check if the bushings are worn out on ur suspension parts.

[AllenRPS13]

yes, that's what i think also... i think my alignment got some problems because i have not checked it for a long time already... i hope that's the reason...

[sykikchimp]

actually cheaper street pads are the ones that tend to outgas these days. Quality track pads like cobalt, or carbotech don't have this problem.

and even Porsche's 'drilled' rotors crack at the holes.

[AKADriver]

I'd hate to crack one of those bling ceramic rotors. The regular metal Porsche drilled rotors can crack, the race cars don't run drilled (usually).

I'd only run a slotted rotor if the car had a problem with water buildup on the brakes. My GTI VR6 had this issue, my 240SXs and other Japanese cars never did for whatever reason. When I'd drive home in the rain on the interstate, I had to lightly pulse the brakes once or twice before I actually wanted to stop to dry the brakes off. This never happened in traffic or at low speeds, only when I'd been cruising at 65+mph for 5 miles or so. Slotted rotors would wick that water away immediately. I think it's just because that car's brakes were so damned BIG - something to think about for those of you with GT-R brakes or similar...

[Silvia Wannabe]

What is drilling for then? I allready know about the weight thing.

[w1ngzer0]

i think its alignment. check your tie rods and tension rods. check if its out of alignment and then also check if the bushings are worn out on ur suspension parts.

who are u talking to.... :confused:

[240silvia]

Rotors baby..... change them bitches!

[XxJaPxOxNeEs23xX]

who are u talking to.... :confused:


To allen180sx

[ledzeppelin240]

Alignment will not cause a shake or shimmy. How does changine toe, camber, caster and making a car drive straight fix a shimmy or shake. It is a pulsation in the pedal when braking, almost like ABS but without the "cool" sound. That is thickness variation and it is a large problem with Disk brakes.

On a FWD car I would not reccomend turning the rotors just replace. There is a lot of components up front and you want all the mass you can get out of the rotor. If you drive your car hard I would not suggest turning the rotors, just replace. Trust me it is worth it.

[S13_Showoff]

I have a question guys, I'm experiencing the same problems and I want to change my discs but I have a 200SX which is the same as the 240SX only that mine is european and has a CA18DET. I live in the caribean and the US is the easiest for me to order parts. Will the 240SX discs fit and brake pads??

[gfisch]

in my area it's about $8 per rotor. not too big of a deal.

Where are you finding the rotors so cheap??
I was actually out today looking to replace mine and two auto parts stores were charging $60 and $40 each for them.

[kaje36]

I am getin close to the same problem.. mine is just around 40mph, and only happens when the tranny isnt engaged or in a gear. any clue about this one?

[Slidin240Wayz]

$8 to have 1 rotor cut