rhys172

I swapped my worn Prodrive pads for some DS4003's last week. The DS4003 pads are the correct pattern for the Alcon calipers, but were each 3mm too thick. I used a sanding machine to grind excess material off each one (very, very messy!).

After fitting the pads, I went for a drive to bed them in. The first 1/2 mile was fine, no problem with pedal feel or stopping power etc. I then started to get a powerful vibration coming through the steering wheel which was present when not braking and worse when braking. I stopped the car immediately, visually inspected the brakes and although I couldn't see anything obvious, I decided to turn round and head home. As I pulled off I noticed that the vibrations had gone completely. Then a couple of minutes later they came back and I repeated stopping the car and setting off again and it cleared the problem again.

I then went through the usual bedding in process without any more vibrations and the car seemed happy under heavy braking.

However, over the last few days when I've been using the car as normal, I've been getting the vibrations back, only under braking though. The wierd thing is that is seems to just come and go and it doesn't seem to affect the actual braking power, it just sounds and feels nasty.

I can't think what is causing it given that it's intermittent. I suppose I might not have ground the pads down exactly level, or maybe the discs are on their last legs, or maybe it's something else entirely. Most of the time the brakes feel excellent with not a hint of vibration and very consistent stopping power.

Any ideas? I'm going to take it all apart at the weekend to see if I can see anything obvious, but maybe someone out there will know what the problem could be...!

davedipster

I've never sanded pads down before, could you not push the pistons back to get the pads in?
Did you use emery paper? cos this is very abrasive and may of got into the pad material. As you said the pads are unlikely to be flat now and that could be your problem.

rhys172

The pistons are pushed right back in! I knew the pads were a little too big as I measured up before trying to fit them. I used a fine paper for a belt driven sander and then finished off with very fine wet/dry type paper. The surface of the pads looked fine after I'd finished and they work brilliantly, it's just this occasional vibration that seems to crop up.

D1CCY

Original Prodrive pads are presumably DS2500, the 4003 material is a race pad and not really designed for road use. There may be issues with getting uneven pad deposits on the discs. They'll probably work fine on track when proper deposits are built up and then get vibration prone back on the road.

Butty

iTrader: (2)

I was warned that the 4003s were for track use only - it does sound like deposits sticking on the discs.
When you are stopping after heavy breaking then the discs aren't cooling down from air flow and the deposits may be at the right temp to come away like they would on track.

Nick

rhys172

That's probably it. Just got back from a good thrash now i've got a bit more confident that a wheel isn't going to fall off or something, and i only got the vibrations once after prolonged heavy use of the brakes. Again, it went after a bit of cooling down and a couple more stops. Shame really as the pads are brilliant when they get warmed up.

Think I should be okay to carry on using them under normal use until I decide who / what / where to get replacement discs from.