hi, when i brake hard the front end shakes like mad. not sure if brakes gone or wheels buckled! what do u think the likely hood?

Its a 97 wrx sti with 4 pot. pads ok discs ok. Could it be the calipers needs servicing? ie seized need change something? if so how shall it be done?

thanks in advance.

 

Could be a number of things.....

Doubt it's a buckled wheel as you'd probably feel that through the steering wheel without any braking.(one of mine's buckled at the minute too!)

Could be warped discs.

Chances are its the same problem I had with my 4pots,they were making an awful vibrating/grinding noise- it turned out that on one caliper 3 of the pistons were and seized, and 2 on the other caliper were also seized (the 2 outer pistons on each caliper were the most fooked). Took it all apart to find the pistons badly corroded. There was a tiny amount of rust behind the seals stopping each piston from moving......

......so I bought some new seals and had some new pistons machined. All back together, brakes are like new, my car now does front flips

http://i40.photobucket.com/albums/e2...t_newseals.jpg
http://i40.photobucket.com/albums/e2...essureSeal.jpg
http://i40.photobucket.com/albums/e2...ot_painted.jpg
http://i40.photobucket.com/albums/e2..._oldpiston.jpg
http://i40.photobucket.com/albums/e2...ewpistons2.jpg
http://i40.photobucket.com/albums/e2...newpistons.jpg
http://i40.photobucket.com/albums/e2...ot_cleaned.jpg

see how you get on

 

warped discs?

 

I agree, warped discs ..... don't know if you sit with your foot on the brake at the lights/junction/roundabout? but that can create hotspots and warping!

Pete

 

I have the same problem but had new disks fitted and its still the same!! do u think new tyres and wheels balanced will sort it or should i just buy new calipers.

 

If it helps....

My brakes were only making horrible noises at high speeds, at lower speeds (<40mph) they didn't sound/feel that different.

It was my assumption that warped discs would vibrate at high OR low speeds, which is why I went straight for the calipers. Turned out it was the calipers, discs were fine- might have been a lucky guess!!

 

check the wheel bearings - they can cause the symptons too

 

Are they red stuff pads? Mine shook like mad when I had them.

 

yes they are red stuff. It was ok when new. I think they are abit harsh for scooby discs!

 

Do a search on here about warped discs - there has been plenty of discussion over the years. Not all of it actually turns out to be warping.
I had an issue with this 3 or 4 years ago - turned out I hadn't bedded my new pads in properly, and there was an uneven build-up of pad material stuck to the discs. It eventually sorted itself out, but wasn't much fun in the meantime.

 

Yep they sure are!!

 

Red stuff pads it is then. I thought my ebc disks were warped as well. Red stuff pads are just not a good product - in my opinion of course. Mine only lasted around 4000 miles anyway, so you should soon be able to get rid of 'em.

 

ive had new red stuff pads and new discs my car juders when braking on the left side.took all apart and gave a real good clean stoped for about a day then started again ,can it be the pads,discs or what
thaanks matt

 

Could be a few things...most likely is pads depositing on discs as has already been mentioned....the problem is that you don't really want to keep using the car and hoping that it'll go away eventually, as you could cause more lasting damage...ie warp or otherwise cause uneven wear on the discs...which will cause vibration...
You could check that there is no run out on the discs...
What I mean by that is that the discs are running true...and not with a slight wobble...This wobble would cause a judder...and would not be so apparent with new discs until the bedded a little...then it gets worse...
To check for run out (if you don't have a dial gauge and a stand) rotate the disc while looking closely at the pads in the caliper...they shouldn't move from side to side or look like they are being "pushed off " the disc when it's rotating...This is only intended as a rough guide looksee approach...which does show up problems is discs are warped or ill fitted...but a dial gauge would be better if you have one...
What could run out on a new disc is ill fitting ...which is usually caused by having dirt/rust on the surface of the hub where the disc is mated. The discs themselves are new...and therefore clean...and should be flat....
If you run new flat discs that are ill fitted for too long...they will be no good as the surfaces will become untrue...so you will need to start again...
I don't recommend disc skimming...
If the discs look lik they are running true...then you probably have glazed the pads/discs.
If you want to keep on using these pads, you could try flatting them ever so slightly to break the glaze...and the try them again....
Hope this helps

 

Very good advise, thanks alot m8. Anyhow,I have ordered a new set of discs and pads yesterday. See what happens!

 

It's been a while since i had my Scoob, but I found red stuff too harsh for road use. I used greens on the road and swapped them for track use. They were great on the road and had very little dust which was a bonus.
They may have changed the compounds since 1976 though!
There are better non-EBC pads around though.

S.

 

have taken off discs and rubbed down the hub and the disc so that they site flat but still does it ,will check the alignnment when spining to see were if they movie,
thanks for your help,
matt

 

Can you feel the brake pedal pulsing when you are braking?....if so my guess is that you have a warped disc...or that your hub is not true anymore...unlikely but not impossible if you have a lot of corrosion

 

You have red stuff pads. Change them for another brand, lightly sand your disks first, and hey presto the problem will go away!

 

Yep, would agree with that approach...if the disc is still running true..could well be glazed discs/pad deposits causing areas of high and low friction...hence the shakes...

 

i drove the car and could not feel much ,but i have a broken leg witch is healing so i cant push to hard or go to fast so im reallying on the misses feed back!
matt