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vibration when braking

Posted: Wed Oct 29, 2008 10:45 pm
by pamike
i have a bad vibration whenever i hit the brakes. it happens 20 mph or faster. it shakes the steering wheel alot.
it's a 90 legacy and has new rotor and caliper and the vibration is still there just as bad. what could it be.

Posted: Thu Oct 30, 2008 2:13 am
by 93forestpearl
A bad wheel bearing or loose inner/outer tie rod can allow the knuckle to shake when braking. I have this on my beater wagon.

Posted: Thu Oct 30, 2008 5:55 am
by Buffman
how new are the pads? What brand pads are they? Were they properly bedded?

Posted: Thu Oct 30, 2008 11:25 am
by pamike
it has a new wheel bearing also. it had the vibration before that. i don't think it's a tie rod, everything seems good and tight. i 'm not sure about the pads. i put them on a while ago and they still have alot af pad left. could they be causing it. if so i'll throw a new set on. if it's not that i guess i have an extra set of pads.

Posted: Thu Oct 30, 2008 12:30 pm
by evolutionmovement
Check balljoints also.

Posted: Thu Oct 30, 2008 4:52 pm
by Buffman
hard to diagnose without being there but my friend's 99 contour had a vibration (decent) when braking over 20-30mph. All suspension was fine up front. Front pads were somewhat unevenly worn, but still had a lot of pad left on them. Car had 99K on it at the time. Rotors were approaching min thickness.

Got new pads and rotors up front. Bedded the pads in per popular bed in procedures and no more vibration.

More often than not on a street rotor you can get uneven pad build up on the rotor that can cause vibration similiar to that of a warped rotor.

If you've replaced the rotor and want to put new pads on it, take some 80 grit sand paper and rough the face of the rotor up (both sides) to clean any pad material off them. Duralast Pads are just fine, just don't get anything super cheap like valucraft or something

Once new pads are on go do a few 35-5mph medium stops, then a couple 50-5mph medium stops, and pads are bedded in (unless pad choice specifiically warns against bedding them in

Posted: Mon Nov 03, 2008 7:29 pm
by Legacy777
I'd suggest rebedding the brake pads, which is what buffman describes at the end of his post.

Posted: Thu Nov 06, 2008 2:22 am
by pamike
ok i'll have to try that. thanks