elnr

I have a Willwood big brake kit on my fd and when they get HOT i get virbration in the steering wheel but when they cool down the vibration goes. I have a feeling the rotors are fitted the wrong way round. Any one know what way the vanes on the rotors should be facing? Down or Up.

Or does anyone have any theories on this?

andrewb70

What rotors do you have exactly? Are the rotors slotted? Rotors also have vanes inside. Some are directional some are not.

This is a directional rotor:

http://www.wilwood.com/Products/002-...R-160-5123.jpg

See the arrow that shows the direction of rotation?

Here is a straight vane rotor:

http://www.wilwood.com/Products/002-...5-ULSV/dwg.gif

It can go on either side.

Andrew

elnr

Mine are directional...and it seems they are on the right way round....so what could be causing this problem?

White94RX

Maybe when they get hot they are deflecting, like warping, then go straight when they cool? Don't know. Maybe the pads are too agressive and bite too hard when hot.

ARD T2

iTrader: (22)

Is that vibration only under braking? Or even when cruising with no brakes applied?

Rishie

SoontobeLS1'd

Sounds like warping. This happened to our WRX coming down the from the mountains.

elnr

Only when braking.

elnr

what causes warping and how long were you using these brakes....only had mine for a few months with not much abuse!

White94RX

Could be a few things: like driving through deep puddles when the rotors are hot, overheating of rotors, lug nuts overtorqued (not sure about this one), etc.

elnr

i know im stumped....goona have to get them checked soon.

aznpoopy

did you break them in properly?

if you break them in wrong you get uneven transfer of pad material to rotor.
this will cause vibration under braking.

this is also colloquially referred to as 'warped rotors,' but the name is misleading.

ARD T2

iTrader: (22)

Yup sounds like warped rotors to me for sure.

jolly

You are experiencing "brake jutter". Check out stoptech.com for technical articles pertaining to pad bedding and such. Poor Brake pad bedding as mentioned by aznpoopy. Might try a more aggressive (racing type) brake pad material for a while to clean off the rotors, then go back to what you are using.

Are your rotors slotted or drilled? Uneven heat expansion, and or hot spots on these type rotors can do that when hot too. Go to a solid face rotor for hot running (track use).

You may or may not have a fixable situation.

I had this same issue on Brembo big brakes once, the first time I used the brand new rotors on the track. Luckily, I turned them, and they were fine.

Good luck!

elnr

uneven pad transfer might be right....one of my rotors has a darker ring on it than the other one....the ring is the same size as the pad buy the other rotor is starting to get darker.......do you think i should keep driving with them as they might even out over time?

jolly

You have obviously gotten them hot enough to know the symptoms.

The fact that it has not gone away argues against your pads helping any more. In fact it may get worse.

Really I think putting on racing pads, and properly doing a bed in may be the only conservative solution. Drive around for a week on the racing pads. The aggressive pads will "clean" the surface of the rotors.

The other way is to take the rotors off and do a "light " grind, like I did. Just take the minumum off that is possible, and find someone who knows how to machine the rotors correctly without ruining them. Afterwards do a proper bed in with your pads.

ronarndt

Find a brake shop that can turn (machine on lathe) the rotors while they are on the car. Taking them off and replacing them requires getting them precisely in place. Turning them on the car gets them trued up precisely, but requires a special rotor turning machine. Have the brake shop do only a very light machining of the surface. Then- start all over with new brake pads and bed them in. If you have warped the rotors slightly or deposited brake pad material unevenly during bedding in, this procedure may help. It will not get better by itself.

This assumes that all of your other suspension components are OK, such as ball joints and wheel bearings and they are not contributing to looseness.