Vibration under braking

[Grrrrrrr!]

Okay, so i've got the old warped discs issue..

'Cept i've changed those already and the problem didn't go away.
Tomorrow I plan on swapping the wheel for a spare set to eliminate anything wheel/tyre related (flatspots, out of balance/bent).

Car was fine before Taupo trackday, but showed up on the day. I had a few offs and a few lockups so flat spots are definately possible, but its not noticable when not on the brakes.

Cleaned up the flange under the disc on the day at Taupo and that wasn't the issue. Will give that another good clean up tomorrow to make sure.


What other things can cause this? Ball joints? Alignment? Steering rack ends?

[Lloyd]

Light braking, heavy braking? What car?
Only when brakes are hot, or all the time?
Open road speed or slow speeds too?

[Grrrrrrr!]

SW20
Any braking.
Hot or cold as far as I can remember.
More noticable at speed but still present at urban speeds.

[KinLoud]

I'm sure wildcard had a similar problem with his Sw20
skimmed disks several times - problem resurfaced

[pc]

I have a similar thing in my EVO. new rotors and better pads has helped a lot, but it is still there once things get hot.
At this stage I am wondering if any play in the wheel bearing can affect it. I haven't replaced any ball joints yet, so don't know if it could be that either.

[iOnic]

Did you replace the pads with the rotors?

[Grrrrrrr!]

No still has the unknown brand (might be mintex m1166) race pads in there. Can throw some EBC yellows or remsa road pads in there.

[iOnic]

I had shudder in the MR2 that changing the discs didnt fix until I also replaced the pads.

[Mr Ree]

If you are running the 1166 compound, then Im going to go out on a limb here and say your shudder is pad deposits on the rotor face.

Mine did exactly the same thing after a bit of track work were I was probably a bit to pussy on the brakes.

My entire dash was vibrating so much mu guages were almost falling out lol

[Grrrrrrr!]

But changing the rotors didn't fix it. I'm hoping that changing the wheels will sort it out tomorrow. Might throw the remsa pads in since they are near new and supposedly decent road pads.

I've run m1166 before on a 20v (daily driver plus weekend hooning), and had no problem. That car had slotted rotors tho.

Will be buying a full set of new rotors anyway, might get slotted if the prices aren't horrendous. Hopefully my contact has rotors in stock now, he was completely out a month ago.

[iOnic]

Also check your caliper sliders.

[allencr]

Deposits will give a pulse at low speed & light braking pressure as the thick & thin places move through the pads. You may not feel it in the pedal but rolling down a slight incline will be jerky & inconsistent when keeping the pedal pressure the same. That ain't you is it?

Hub run out? Disk run out? Bad hub to disk mounting surface.
Also, tighten lugs in criss-cross sequence & 2 steps?

[Grrrrrrr!]

Calipers should be good, they were completely reconditioned by the local brake specialist and only fitted about 300kms before the trip to Taupo, along with new braided lines and fresh fluid. But yeah, will check them out.

[92mr2paddy]

if your discs are grooved or warped then the pads will be too, changing the disc or skimming them will do nothing because the old warped/grooved pads will re-groove/warp the new disc. i had the same problem in my hiace the steering wheel shuddered so hard it was almost punching you in the chest on downhill braking , new disc + pads, perfect!

[B_giB]

Check all bushes too?

[Grrrrrrr!]

Still waiting to hear about the rotors. Swapped the wheels over and cleaned the flanges up and its better, but still vibrating. Also doesn't stop at all well on the cheap chinese tyres on these wheels.

[phoenix]

Have you swapped pads yet?

I cooked a set of pads at the track, became passable on the road but as soon as they got any heat into them the car turned into a bucking bronco. Swapped those out (without doing anything to the rotors) and it was completely fixed.

[Grrrrrrr!]

No, it started raining and i had to go have some fun in the FSAE car.. so it'll wait till i get time + good weather.

[Akane]

Had the same issue with some budget slotted rotors.

disc machining + new pads combo = problem solved.


I wondered if the cause of the problem was heavy braking (from 220kph down to 0) and then pressing and holding on to the brake pedal for a good 30secs to a minute while the car is stationary. That's how mine started.

[Grrrrrrr!]

Problem is fixed. New rotors and fitting the road pads plus attacking the hub flange with a wire wheel on the end of a drill to remove all the crud has solved it.
Might throw the old rotors back on to see if they were the problem, since it'd be good to know what exactly it was.