Possible Problems, Brake, wheel shake Options

[mr_dude]

When I brake at high speed my steering wheel shakes and brake pedal shakes.

I checked for warped rotors and they were well within spec. I'm going to see if my tires need rebalancing. I heard it could also be worn wheel bearings, though I'd think that wouldn't be just a braking problem.

Anything else I should check? tia.

[celicaboston1983]

isnt the pedal suppose to shake if you have abs?

[Blakout16]

abs only goes active when u stomp on the f'er umm at high speeds like 100+? mine sure does a little bit at 100+ and ill check for the brake pedal shake...

[playr158]

speed doesn't trigger abs my friend

you can go 5mph and hit abs

you just have to stomp it and lock the wheels up to trigger the abs system

[Newbie]

check the balance of the tires.. Although, I'm leaning towards warped rotors.. Do you use brake hard?

[mr_dude]

I checked for warped rotors and they were well within spec.
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check the balance of the tires.. Although, I'm leaning towards warped rotors..  Do you use brake hard?
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It's not noticable at low speeds. What's this about abs?

[MonsterBOX]

could be a frozen caliper i had one and didnt know it except that breaking was very choppy like it would lock up time to time and not let go

[LewFX]

you sure nothing is bent? a rod, arm, axle, belt, etc.

[mr_dude]

Monster - good suggestion, I wonder if it is a caliper problem, though they don't lock up.

Lew - I'd think most of those (except a bent belt would be a problem for driving/turning/moderate braking, whereas I'm only getting problems braking hard. But if you know of any way one of these could cause my problem I'm all ears.

[Galcobar]

Could be simpler -- alignment problem. But the fact it only happens when you're braking suggests it is something in the braking system. Possible bad master cylinder or proportioning valves. Look for fluid leaks as well.

[GT4WRC]

My money is on the rotors if the issue is from high speeds. Sudden heat build up causes the rotors to warp slightly leading to the symptoms you describe. After stopping, rotors cool down and 'straighten' up again. This is why it may not be noticeable at lower speeds as there isn't such a build up of heat.

If it was a tyre issue, you'd notice it while driving, not just during braking. Same again with bearings. Alingment? Characterised by the car pulling to one side or the other.
Frozen caliper - definately not. You'll only then get a decent braking force on side side - again resulting in car pulling to one side. Rotor would also get very, very hot and leave a blue 'hue' on the surface.

When you say 'within spec' spec, I assume that you just measured the thickness. This will definately not tell you if a rotor is warped. My advice would be to try some different rotors and more than likely the problem will disappear.
Gary

[mr_dude]

When you say 'within spec' spec, I assume that you just measured the thickness. This will definately not tell you if a rotor is warped. My advice would be to try some different rotors and more than likely the problem will disappear.
Gary
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Hmmm, good info. My friend and I first visually checked them against the surface of the brake pads to see if they got nearer or far-er.
We couldn't see any warping so we used the rangefinder on a set of calipers to verify. The variation we got was something on the order of a tenth of the Chilton's spec.

[macavely]

when braking hard its is normal to have ur wheel and pedal shake... there are alot of things to consider.... if u brake on an uneven road that will make anythign shake...

[mr_dude]

when braking hard its is normal to have ur wheel and pedal shake... there are alot of things to consider.... if u brake on an uneven road that will make anythign shake...

This isn't normal.

[gtcelica94]

get the tires balanced . thats what it is. my car used to shake when i braked but only around 60 and up but i got my tires balenced and its good now, also check ya tires make sure they are still good. come to find out i need 2 new tires

[GT4WRC]

Very cheap and simple way to eliminate wheel / tyre problems. Rotate the wheels - ie front to rear and vice versa. If problem vanishes, then you know it's wheel/tyre related. If it stays the same, then it's the rotors.
Gary

[mr_dude]

I'll do that, thanks. Just gotta dig the wheel balance warranty information out of the file cabinet.

When I checked the rotors I rotated the front tires and the problem went away for about 10 miles.

[MonsterBOX]

well i had stock rims and had them balanced like 3 times and i had wobble all the time...i could never figure it out..then i put on some 17's and new tires and no wobble

[Galcobar]

When re-balancing the tires on the wheels, did you also rotate the wheels on the car to even out the wear?

[MonsterBOX]

not necessarily..only if you need to you can

[GT4WRC]

well i had stock rims and had them balanced like 3 times and i had wobble all the time...i could never figure it out..then i put on some 17's and new tires and no wobble
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More than likely that one of the tyres was flat spotted.
Gary