Would like to get people opinion here. Have an 02 Sti with a steering shuddering under high speed braking but under low speed no problem at all when braking. these are so far have been check:

- brakes pads & rotor all normal wear
- have try replacing the brembo caliper as well with a japan surplus but still same problem
- replace hub assembly n wheel bearings
- replace damage rack holder bushing.
- all underchasis bushing is fine
- wheel balance and alignment
- air pressure on each wheels is even
- tie rod and rack end replace
- clean abs sensor even though no abs light coming on

any suggestion guys?

 

Discs are warped I reckon. You normally feel it more when braking from high speed's.

 

classic warped disc symptoms on a newage, pun

 

As above, classic warped disc syndrome. I had really bad vibration when braking hard, totally gone now new discs are fitted. You can avoid the discs warping by doing the last few miles with easy braking. This stops a really hot pad sitting over the disc and warming up a small section.

 

I will be interested to see the outcome of this. I had the same with my car, replaced everything with new and still no fix. Even brand new disks and pads made no difference at all. The main stealer said it must be warped alloys so even replaced those, still no difference. Track rod ends, track rods, bushes, suspension, etc all replaced still no fix.

 

Crap/rust between the disc and hub face maybe?

 

or the new discs are warped, very possible, new discs can be

 

Cleaned the faces when the new discs were fitted.

My point to the OP is that it isn't necessarily the discs. Don't do what I did and just throw cash at the problem. Have each item checked if possible before new items are unnecessarily fitted.

 

Agreed, but maybe more common is Halley's Comet.

 

have try cleaning the abs sensor unit and will try to test it out again. rotor was also replace and still same problem

 

think you'll find many a new disc fitted are warped, i'm in the trade and change more disc's than i've seen the comet!

 

That's just a bit scary, would presume this would have to be during manufacture, worrying that variance on a rotor is so slack that it can be felt despite brake geometry tolerances. Certain manufacturers will be worse at this than others, it's the nature of making stuff. Care to name a few (if discernable)?

 

will have the rotor disk check at the machine shop for warpage

 

have the rotor rephase but still no avail problem is still there

 

had same proble on my car, heavy judder under breakin, one of the front shockers was knackered, replaced it and now its fine.

 

to be honest no subaru's as yet but, bmw, a lot of cryslers, escorts, a few other french pants cars, can be that they used them too hard too quick, but yes could be any car

 

wrxhewitson: will try your suggestion

 

have check both front n rear suspension all seems fine. anyone has any more ideas?

 

if you can get the car in a brake roller tester, try that but you'll have to get the rear wheals off the ground, that'll def sort out if it's the brake discs, make sure all joints are good and get the wheels balanced

 

phmem: yes have done already wheel balancing and chassis align. Brake disk has already been replace also

 

you need to check the disc's cos it all seems to be leading to them, as i said new one's can sometimes be warped

 

p12men: have also rephase the rotor but still the same problem

 

thats why i think it's the disc's, wish i could drive it, then i'd know

 

anyone has any more ideas??