Guys,

How do you know if you've got warped discs?

My car MY05 STI, when braking gently approaching a junction for example the car sort of shudders if that makes sense?
Like there is normal braking and then a wee jolt, more normal braking and a wee jolt?

Is that warped discs?

 

Sounds more like deposits from the pads.

Give the brakes a good use: a few stops from high speed to get them hot, see if it removes the deposits.

Oh, and don't sit with your foot on the brakes when you come to rest

 

Pad deposits - really?

The pads are EBC pads, been on for about 16K so far.
This has only started happening recently, I've also tried getting putting a lot of heat in them, but no joy.
There is also a very slight shuddering in the steering under braking?

 

Yes id go for pad deposits too. Ive had it with my focus a few times. Just nail them somewhat to clear the crap.

I believe disks dont really warp, more of them get contaminated, and cone warp giving un even pad ware and eventually crack.

Hope you can sort it!

 

So by nailing them then.

Are we talking about driving around a constant 50/60 and just applying some pressure on brake with left foot

Or

Are we talking about finding an empty road and repeated braking from high speed to low?


Its being left in on Monday for a service, needs new rear pads as there's virtually nothing left on them and I've asked the guy to look at the front discs for me also.

 

i guess you should be able to see deposits. any marks or bronzy colouring.

I guess the idea is to just ware ware where the pad has bonded to teh disk. Dont want to cause too much heat in the disks or they will crack. so perhaps just a good few fast hard stops. Warm them up a little first tho, and be careful you dont run out of brakes.

Or get your disks skimmed.

best bet is to see what the bloke says on monday i guess!

 

Warm the brakes, then do the second option: high speed stops.

If it doesn't clear it, you'll need to get run-out checked, it's done using a dial gauge.

If they are warped, buy new.

 

Thanks folks.

The chap on Monday will know exactly whats wrong.
He's an ex SWRT mechanic.

Time will tell.

 

I'd be interested to hear the results of this. Ive got exactly the same thing on my car. Drove up to my mates house in Lanark (fairly steadily). Parked the car for three days and then drove it back home (County Durham). On the way back I noticed the onset of the "shuddering" when coming to a stop.
Ive had various suggestions from deposits to warped discs. Keep us posted please.

 

We'll time will tell.
After researching pad deposits yesterday I looked at the discs after work.
They don't look like they got deposits on them, and I don't think they're warped as such.

Found a quiet bit of road on the way home and on hard braking I don't feel any vibration on the steering and nothing from the pedal

On gentle braking there is a little bit of vibration, and a very slight pulse back through the pedal(Although I could imaging this bit!)
Definately a shuddering/jolt type of thing as I've tried to describe.
Discs are a bit worn - got a bit of a lip at the top of the disc - standard discs.
The pads are EBC redstuff, which seem to get bad press on here.

 

EBC pads... There's you're first mistake.

Most likely pads deposits, a harder compound pads will clear these quickly.

I do a fair amount of track work and have never warped discs. You won't warp discs with normal road driving and if you do it's by driver error.

 

I'm thinking of just telling the guy to change the front pads anyway, plus they're knocking a bit too.

Leaving the car up shortly so he can work on it first thing tomorrow.
Local specialist - ex Subaru & Toyota WRC mechanic called Iain Bishop

 

New discs required and as a result new pads (He's putting in Ferodo)

 

OK, maybe its not been "normal" road driving and regardless they're slightly warped and quite badly worn anyway he tells me.

 

When tested for run-out, some discs seem fine. Unfortunately, discs work at temps. way above what they would be when tested! It's often then that they warp. (from experience!) Also, get the wheels balanced. The static balance could be out?
JohnD

 

Wheel balance is alright.
I picked it up yesterday - you don't actually realise just how big the discs are.
Yes you can see the diameter is big, but you don't normally see just how thick the discs are