trout2

Can anyone tell me if it is possible to fit a spare set of 4pot front calipers and disks to the rear of MY99 Impreza. Also is it normal for AP front disks to warp after one track day.

Thanks

AvalancheS8

You might be able to fit 4 pot brakes on the rear, but you probably wouldn't want too. You'd have too much braking at the rear and would be likely to lock the rears with the foot brake - not good. Even heavily tuned scoobs do fine with at most braded hoses and better discs and pads on the rear.

No it's not normal to warp good discs like that. It suggests one or more of: poor fitting, disc machined out of true, insufficiently careful bedding in or un-even pad deposits due to stopping while the discs were still hot.

Tone Loc

iTrader: (1)

No and No.

The handbrake acts on the inside of the rear disc and are a very different offset, also the mounting points on the hubs don't suit the calipers.

The AP's really shouldn't have warped, what calipers and pads are you running and are you sure they are warped (maybe get some wet and dry onto the pads and discs?).

Tony.

trout2

I run the brakes in for 350mls before the track day. I did a cooling down lap after each session and kept my foot of the brakes when stopped. The pads came with the kit, I think they are 2500 and were fitted by a dealler.

AvalancheS8

Time for a word with said dealer then...

trout2

I think they are warped because the steering wheel vibrates when stopping

ozzy

It's not very common to actually 'warp' the disc. What it sounds like is pads deposits more than warping. I maybe wrong, but I don't think even Mr Felstead has warped a set of AP discs and he uses them more than 90% of Scoobynetters with his trips around the ring.

I had uneven deposits on my Godspeed discs and the vibration was terrible under braking. Some big stops and progressive breaking-in on the discs cured all my problems.

The Wet 'n Dry trick would clean the surface and give you a better idea of the problem. The discs need to be measured correctly to prove that they have distorted.

Stefan

trout2

Can you normally see the deposit

AvalancheS8

No, not usually, at least, not easily.

ozzy

Likewise, on my discs I couldn't tell if there were deposits or not - it just vibrated like a barsteward. It was only slight under light braking, then went mental when pushing hard.

I did think they had warped, but after speaking to Ian and several mechanics it's extremely rare on road cars with good quality aftermarket discs.

Not impossible, but I'd look at the more likely causes first .

Stefan

trout2

Just shot to try some hard braking to get rid of the deposit but did not make any difference. When the disks are cold they are fine but once you start braking hard the hole car shakes. (the disks are grooved but not drilled).

ozzy

If the discs are truly warped, then surely they will have distorted no matter if they are hot or cold

You could put some wet & dry between disc and pad and drive around very slowly to clean them up. John Felstead posted some details on the best practice a while ago.

Stefan

johnfelstead

I have never warped AP disks. I have had the same problem you are having with DS2500 pads on track, they can leave uneven deposits.

I dont use DS2500 anymore, I find Mintex 1153 work well, i have recently been using various new compound EBC's and find the ceramic reds to be very good, both on the road and track. I tried some new compound Yellows yesterday and they were a great track pad, but not suitable for road use.

trout2

Thanks Johnfelstead. I will try the Mintex.

Cheers