Worn brake pads, or more to it?...

[Robertjwebb]

I've got a LCR and went to Snetterton on a trackday on Monday. I did a few slow laps to warm everything up and then when braking from 120 on the main straight for the first time I got some brake fade once I got below 80 which I wasn't expecting as I wasn't pushing it very hard before. Then when braking for the next corner the brakes made a noise simular to what you get when braking when the disks have a thin layer of rust after it's been raining.

I took the drivers side wheel of and I've got at least 3-4mm of material on the pads. I only checked the outer pad on the passanger side and that looked about the same.

Since then when I brake normally I'm still getting the noise only much quieter than if the disks were rusty.

I've ordered some new pads but it's strange I'm getting the kind of noises that you get with worn out pads with still 3-4mm left. Has anyone had this kind of propblem in the past?

 

[Reg]

Track driving is significantly more stressful on components, as I'm sure you appreciate, and seeing as the LCR is a fat b'stard it gives the brakes one hell of workout! What do your disks look like? 3-4mm isn't that much, over half worn I'd say, so there is a lot of heat going through a small amount of material.

 

[smoothuk]

Would the brake fade not be down to the fluid needing a change, and do you have grooved discs on, as mine make a hell of a noise under breaking when there really hot..ie, the speads you are talking about.

 

[RikH]

could it possibly be a slight warp of your disc, miniscule amount

 

[Robertjwebb]

Thanks for the replies. I don't think it was a problem with the brakes overheating. Before I noticed them fade I had done 3 sighting laps (brakes hardley used), 15 min break, then 2 slow laps no braking too hard. If anything I'd say the brakes were too cold. After the fast lap when I noticed the problem I took a cooling down lap and went into the pits. Then 20 mins later I did another slow lap and noticed the noise like something metal grinding away on the brake disk while braking. After that I packed it in for the afternoon. Especially after a tvr tuscan fried his brakes and went off the track in a blaze of tyre smoke On the way home I didn't notice any noise at all and but yesterday I noticed it when braking at low speeds when and even then I can only just hear it over the noise of the engine.

The disks look ok, not excessive scratches and only a very small lip around the edge (less than 1mm). I've never noticed and vibration through the brake pedel or steering wheel under braking so I don't think it's a problem with the disks either.

 

[Reg]

Change of pads and some new fluid should see them fit as a fiddle. Just before I sold the LCR a few weeks ago I took it for a 'spirited' drive, and saw smoke pouring off the front wheels, from the pads. That was on 1/4 worn Ferodo DS2500 pads with pretty new fluid in the system. They still worked fine, although the smell was pretty grim!

 

[smoothuk]

go for the motil RBF 600 fluid too, very good stuff

 

[Robertjwebb]

I've just had a box of DS2500 pads delivered to my desk I'll get them fitted tonight and see how it goes.

 

[RikH]

im just changing my system right now for ds2500, ebc drilled and grooved discs and goodridge lines

might well be worth getting the lines as well, only another 50 or so while your at it

 

[Robertjwebb]

Well... I made a start on replacing the pads this evening but just after I took the first pad out it started raining so I put it back in again. Upon removing the pad it didn't look that bad I'd say it's about half worn compared with the new set. I then attempted to remove the pad on the back of the disk but wouldn't budge. However i'm not too sure about the condition of the disks.

There's a bit more of a lip on the back of the disk and you can feel a slighly raised ring running around the back (around the middle). Not completely smooth like the front. The car has done 17k miles and I guess are still on the original disks. Unfortunately I have no way of measuring the thickness of the them accuately. Roughly how much of a lip on the edge of the disk can you get away with before they need replacing. On the way home I did notice the noise coming from the brakes has now stopped but I've been taking it easy over the last few days.

 

[777cupra]

Apprantly the inner pads wear quicker than the outer ones