So, long story, for 6 months I've had severe brake problems with my Evo. They started on a track day last year, and it's been making me crazy!!

The brakes feel like they have severely warped rotors. To keep the story short (multiple rotors by now) have been on the car, and the ones on them now are new and have been trued. With the wheels in the air, you can pull both sides every which way and there's no unexpected movements.

The car has been in multiple shops now looking for the issue, so I'm going to post what's been changed/swapped and hopefully someone might have a clue what to check next.

Rotors trued, pads have been swapped between Ferodo DS3000's on the track, and DS2500's on the street. Currently I have 2500's up front, but whatever 'problem' I have has been there regardless what pads/rotors have been on the car. It goes away when 'new' pads are on the car, but hours of driving later it returns. Hence, the shops think all's well, on their short test drive.

Martin of Gyrodisc suggested wheel bearings. I just changed both. The driver's side felt a little 'sandy' but not really bad. I've been a mechanic in a past life, so I've spun a few bad ones for reference. Put everything back together, and it felt better, but it's still shaking, the vibration is apparent in the steering wheel. the car does not shake at all under acceleration or cruise. One thing I noticed this time around is my passenger tire seemed like it just had a track day on it, where the driver's doesn't look nearly as bad.
(Last track day I went to was 4/22, 2 laps in on new rotors/pads the vibration came back.)

Here's some shots of the passenger tire;

 

WOW, weird....
When is the last time you checked alignment?
I would check any parts in the suspension that can move: A-arm bushings, tie rod ends, ball joints, top strut bearing, etc.. You may have a hard time checking as it is normal under accel, but while braking there is enough force to move something more than it should, so really tug on things with a pry bar and compare sides for amount of force used. Visual inspection would not be enough in this case.

 

It doesn't viabrate during accel or cruise, but it does on decel and braking?

Make sure the hubs aren't bent and the mounting surface on the hub and the rotors are CLEAN! take a grinder with an abrasive pad of the surfaces.

This is one of those detailed problmes that's hard to help with over the interwebs.

 

first off, bringing street tires to the track will do that to ur starspecs.... the braking issue, forget getting rotors trued... are u using 2 piece rotors? If not, u can warp 1 piece on a track on the first lap.... literally... my 2 piece rotors lasted me 40k miles, 1 piece, 3 minutes... using motul 600 or equivalent brake fluid? If not, ur boiling the brake fluid... If ur tires and brakes are doing this to u, u obviously are driving like ur supposed to on a track, and u need to step up on the braking and tires u choose for a track.. I brought street tires to the track my first time, and my tires disintigrated... They were kdw2's which have nothing on the starspecs, but i wouldnt risk my starspecs on a roadcourse... ill be further help when u answer my questions

 

Yea, using Motul 600 ATM, flushed 3 months ago. I'm going to flush again after we get back from vacation with some Amsoil anyway.

The treadwear was from 2 months of street driving. It just reminds me of after a track day in comparison.

It's only on braking, hubs are brand spanking new as of the start of this post. It's been aligned a number of times by a very good local shop here in Seattle. I went over all of the mated surfaces with a rag and brake cleaner to the point of near polish, Martin gave me a heads up on that. I torqued all of the hub bolts and lugs too just to be sure w/ a torque wrench.

 

Gah I split the replies up a bit. I had 2 piece rotors on the car when the initial vibration started, since then they've had the blanks replaced, then finally disposed of for 1 piece veined rotors from Gyrodisc. The rotors were turned immediately after the 4/22 track day and they were .004" out, which is nothing.

 

You still have the vibration with new rotors and non-Ferodo pads? Sounds like you've bought new rotors and then run them with DS2500's and/or DS3000's - but perhaps I've misunderstood.

I ruined a set of front rotors with DS2500's though I still run them on back without problem.

 

Warping is a misconception. Its actually pad transfer (99% of time). Try a different pad company.

Do you have air ducts?

 

I would look for a suspension or alignment problem-- Brake issues you will feel in the brake pedal and you haven't said that and I think from all the changes you have made, you eliminated that. Check tire balance, get hub rings if you are running aftermarket wheels. Get rid of spacers if you have them. If you can put the car in gear on a lift at idle--then you can look for rotating out of round issues with some chalk or a mic.

 

Bad tie-rod ends (inner or outer) can cause severe shaking during braking.
It usually is a much faster shake than with warped rotors.
It can also cause your alignment to be out of spec and give you strange tire wear.

 

That seems like the right avenue. The last alignment I had the tech said the tie rod ends were extremely hard to move, and only 1 tire looks like the pics I posted. I'm guessing Monday I'll swap those out. The vibration is severe compared to a typical warped rotor.

 

Update: Back from Pike's Peak. I took the car to the Mitsu dealer finally on Tuesday. They spring checked the tie rods, and pressure checked the balljoints, along with checking hub trueness and the rotors on front and rear of the car. They say warped rotors since there's no ability for these calipers/brakes to float, all vibration is directly transmitted thru the brakes. they measured .014mm of runout, and say factory is .003mm max.


I also had the alignment checked yesterday. The car was exactly where it was set by Group2 for alignment specs. -2.5d camber front, -2.0d rear, .062 toe out. It now has a factory alignment with suggested numbers from Mitsu to avoid any alignment issues. The vibration still exists.

I called Martin @ Girodisc back while at the dealership and read him the numbers they told me. He offered to inspect the brakes and suspension next weekend (after the 4th) in trying to find a resolve to the vibration. He didn't think .014mm should be enough to cause my delima.

 

So I just got back from Girodisc, and here's the full story of what we could determine.

Warped rotors were the cuplret. The dealership is now 2/2 on diagnosis of issues with my car over 2 different 'high end' shops that have looked at it...

The new rotors were put on the night before a track day. Martin tends to think they were shocked into being warped. (Brought up to temperature too rapidly on unseasoned rotors.)

Since they were turned on a brake lathe after the track day, he tends to think they were cut wrong. Since these machines don't cut both faces at the same time, there's nothing that can prevent the rotor from having two different angles on the inside and outside faces, causing the disk to have more of a trapazoid shape than being true face to face, this would cause the massive vibration I was feeling, as the unevenly cut rotor wouldn't be on the same axis anymore as the hub of the car (which were perfect for trueness btw!)

Another thing I wasn't aware of, rotors have a bed in process too. Be sure to check with your rotor's manufacturer to determine the correct break in procedure for your rotors. Don't have 6 months of misery when driving your Evo that I did. I swear I love my car again!!

 

my guess is that the rotors are warped