I'm stumped - braking vibration that isn't consist

audi_s_ate, Mar 30, 3:39pm
Isn't consistent.
Just bought an 03 accord euro auto (2.4)It has a slight braking vibration - part of the reason it was cheap. Took it on a long trip today for the first time. After overtaking the vibration turned quite violent right from 120ish to 95ish - was the same after the next corner - speed around 70.
The next corner it settled down to a slight vibration - like normal and continued like that for the next 90km home.
Initially when I bought it I thought warped rotors - now I am not so sure - sometimes the vibrations are imperceptible - other times much worse - not dependent on speed.
Just jacked it up and tried to wiggle the wheels as a wheel bearing I thought could be an issue. Couldn't budge it by hand - it turns freely and has notypical wheel bearing noise when driving.

So any suggestions!! Thanks sorry it was so long.
mugenb20b, Mar 30, 4:07pm
I would replace the rotors regardless and bleed (flush) the brake hydraulic system. Pistons inside the brake caliper may be sticking.
sas777, Mar 30, 4:09pm
Get it up on a hoist and check every joint, bush, mounting and weld you can see.
Look for accident damage, poor repairs.
Get the rotors checked for wear and warp.
Check shockers and springs are factory spec.
Have the tyres balanced.
Don't go over the legal limit either, you'll likely kill yourself (or others)
scuba, Mar 30, 4:13pm
I wold get someone to discuss the problem and road test before replacing anything.
see what they think is the issue first. or also as above -
franc123, Mar 30, 4:26pm
Bushes and balljoints are the first thing to check, you may have to get it on a 4 post hoist or run the front up on ramps to do this properly, ie have the weight on the wheels still. IF there is slight warpage or thickness variation in the rotors any front end wear magnifies it. Partcularly control arm and torque rod bushes
r15, Mar 30, 4:30pm
bet its the discs. only when they warm up.

replace the discs and the problem will go away
audi_s_ate, Mar 30, 4:34pm
Ok you guys are awesome.
@2
just checked caliper pins to see if they were sticking - brakes have a relatively new flush according to the dealer history - will do anyway when I get new rotors - opinions on a resurface or new! I have always gone new but would hate to get a new pair and have it do the same thing.
@3
No accident damage that I can see - its a very straight car underneath and on top. Shocks and springs are factory
Tyres balanced - great point will do.
Its not being driven anymore until its fixed (initially brake shudder was and is at the mo very minor - hence why the big trip today.
@4
Yes will get a (real) mech to road test before doing anything
@5
Bushes look fine on visual inspection but will get mech to check this.

Again thanks for your help - I now have somewhere to go.
r15, Mar 30, 5:18pm
discs are cheap - however depending on the car (and i dont know anything about this model)fitting the discs can be a mission and therefore a more expensive job.cant beat new ones.

if a disc only warps when hot, then the skimmer is likely to not improve the situation much
skull, Mar 30, 5:24pm
Why not shift the front wheels/tyres both to the back and see if anything changes, it will cost nothing and eliminate a couple of possibilities. To me it really does sound like a rotor/heat problem though.
audi_s_ate, Mar 30, 5:37pm
@9 Cheers, will do a tyre swap tomorrow - didn't get any worse or better with heat - on way there was fine and apart from that small moment halfway home they were fine (as in slight vibe) too. Could be a combo of rotors and worn bushings. Cheapest I have found for rotors are 127 each (DBA I think ex BNT) - any recommendations for brand/store !- they have to order in anyway so prepared to go nationwide.

@8 Fitting these discs are as easy as any I have done previously - straight forward.

Thanks guys - keep adding on if you think of any thing else. Will keep everyone updated as to outcome/fix in the coming week.
cessna3, Mar 30, 5:55pm
It will probably be the rotors, my 02 odyssey had a similar problem, put new rotors on & stopped the vibrations completely. I got mine through Midas for about $95 each.
xs1100, Mar 30, 6:18pm
try autostop very underratedbut they can either machine yr discs or sell u new ones
pc_uncorrect, Mar 30, 7:18pm
Check out the, Brake proportioning valve, may need replacement.
ash4561, Mar 30, 7:27pm
Id go with a bulge in a tyre might see it if inspect it put the spare on. Could be more than one. More likely in tyres you have never heard of before, Or else the wheels might need balancing. How much tread and brand of tyre.
llortmt, Mar 30, 10:30pm
LOL wheres that then!
I suppose some sort of bias valve must be built into a modern ABS unit but not like your talking about.
audi_s_ate, Mar 31, 9:26am
The tyres are bridgestone front and dunlop SP rear - both made in japan. Def not cheap options. All about half worn and in good shape (no abnormal wear).
Braking seems even - doesn't pull to left or right/lock up rears in hard braking situations - not a proportional issue IMO - just got a VTNZ wof so I am sure they would have check braking bias.
Am going to swap tyres now.
cjdnzl, Mar 31, 10:18am
I'd go with rotors.Both rotors are probably warped.If they happen to be in sync the pedal will buck violently, when they are out of sync the bucking is less.very time you take a corner, or even just make a mid-course correction the relationship between the front rotors changes, and with it the braking reaction.I had this with a near-new Commodore, going down a steepish hill just before Utiku (south of Taihape). I thought I was going to lose the entire front end, the whole car was shaking.
The brake shop pulled the rotors, skimmed them on the lathe, no more problems.I watched them doing the skimming, both rotors were well out of true.
audi_s_ate, Mar 31, 6:06pm
Thanks for this - sounds exactly like what has happened. Tyres swap didnt change a thing. Will go for a new pair and new pads - install them hopefully Wed and report back.