DT

I have a slight warping on my AP discs, noticible at slow speed and light braking, which is really irritating. Although nearly new I can't send them back as they were second hand. (all the usual bedding on done properly) Will a light skimming sort this?

johnfelstead

you absolutely sure its warped disks? You can get these symptoms from glazed pads. Take the pads out, run them on some course wet and dry paper on a flat surface until they are matt again, then try them.

DT

Pads were new 3000 miles ago and the problem was evident then, so I think its the discs.

Sigmund

I've had this too.. Thougt it was warped discs but it wasn't after all as it went away after some good braking. If you've got the "right" pad and use the brakes a lot lightly I think they can develop something which feels like warped discs..

This sounds silly I know...

Just try to do some heavy braking and see how it affects things.

johnfelstead

what pads are you using?

TonyBurns

iTrader: (3)

Warped discs are more likely to be noticed when you have done some hard braking then it feels like one of your wheels wants to come off
Like John says, it could be your pads as this doesnt sound like warped discs

Tony

DT

John, they are Mintex recommended by Craig H of by New Age. Can't remember the type as I've chucked the box, and the pad details are not on their site.

Tony - Hmm confused now then. High speed braking no problems - no noticable wobble through the wheel. Its only aparent on light braking like when slowing from 40/50 for a junction. I was told that this was prob because there's only a slight distortion and when you brake hard the clamping forces are such that it doesn't get the chance to move about. Thinking about it now i'm not sure that makes sense.

This may or may not be related but on doing slow turns, like when parking, I can now hear a nasty knocking from the front wheels. Is this my wheel bearings going? Is this a result of me putting up with the brake wobble for a couple of months ( that came first), is that causing the problem or is it unrelated. Now booked in the garage Thursday week (25th).

Car is a 18mth old 01 WRX with 23k on the clock.
DT

johnfelstead

if your on M1155 or M1166 then i wouldnt be at all surprised if you glazed the pads. Try Ferrodo DS2000 pads, they dont need much bedding at all and work very well on the road. Do get the bearings checked, i doubt that is related to your judder though, that usually leads to pad knockoff where your constantly having to push the pedal further to the floor after corners.

johnfelstead

oh, one more thing. to check if you do have warped disks is easy. take the wheel off, bolt the disk bell up solid then spin the disk with a dial guage on the disks side and see if it goes in and out.

Just had another thought too. You have a second hand set, its super critical when you install this kit that the hub surface/ disk bell surface mating is totally clean. Its quite commom for there to be some debris on this surface that causes the disk bell to not sit square, gives the same effect as warped disks. One final point, do you have them on the right way round, they are handed left and right.

DT

Excellent advice John thanks. 1155's sound familiar. I'll the wheels off tonight and do as you suggested. Dispite being told that they had done only around 20 miles they felt wobbly from the off, which might suggest there was some debris on the hub.

Appreciate your help.

DT

DT

Ok had the brakes off at the weekend and did as suggested. Big improvement but still a flutter through the wheel at gentle low speed braking. Will this go away once they have settled in a bit?

Putting the disc faces together they looked flat - no obvious signs of warping.

Took the opportunity to paint the calipers black and colour the AP lettering yellow. looks well smart now.

mutant_matt

DT,

The calipers should have been black with yellow lettering already???

John,Really? I had 1155's in my AP4's and I thought they were fab for road and track. Are you talking about glazing the pads if not run in properly or some other way?

Cheers,

Matt

DT

Mutant,
They were a faded black, and the lettering was not picked out in yellow - older model perhaps - bought second hand. Anyhow spruced them up and they look fab now.

I was abit puzzled by the glazed pads comment too. I thought the grooves were there to deglaze as well as remove gasses that build up.

johnfelstead

If you ponce around on the road with anything harder than an M1144 its very easy to glaze them. even with groved disks.

DT

LOL thats told me then!!!

mutant_matt

Thanks John,

That means that I don't ponce around on the road and obviously use them as they were intended

Matt