Rear pads not covering the whole rotor on our Clio. Why?

[Yiannis197]

So why is that then? Anyone knows a way around it (apart of course changing the calipers with aftermarket ones)?

I initially noticed that on my old discs and now - expectedly tbh - on the new ones. Basically the caliper/pad combination is not wide enough to cover the whole rotor area with compromises to the braking performance (obviously) and to aesthetics as the area of the rotor not coming in contact with the pad gets rusty and looks awful. The pictures show what I mean.

OEM rusty, nasty, terrible rear disc








Brand new one, OEM rotor with aluminium hub.



DSC05818 by YiannisR27, on Flickr




After a few months.






So is this one of the 'Friday afternoon' French designs?

 

[Pav]

when washed my car last week I noticed the same thing..the edges are just not covered by the pads...never had that before...i know that u had u pads replaced not long ago(think)..mine are 18 months old....will have to strip them when a bit warmer and might get better results..

 

[Yiannis197]

Yours definitely need stripping and cleaning mate as the upper side shouldn't be like that, or even abusing the brakes a bit to wake them up!

Mine are done every 6 months and I'm sure they perform as they should, to be honest it's not the caliper having seen better days, it's the fact that the pads are not big enough to cover the disc in the first place!

 

[Foxspeed]

more to do with "production tolerance" I would say for the caliper/pad/disc contact area ie pad face is slightly too small for the disc face but if the pads
are made slightly bigger it wont make a difference to the coverage...

front discs can be the same on various motors

 

[fano45]

Fair enough. How do we prevent the rust issue

 

[Gez]

You can get a painted disc and then only the paint where the pad wears will come off, then the rest of the disc will stay coated with the paint

 

[Yiannis197]

more to do with "production tolerance" I would say for the caliper/pad/disc contact area ie pad face is slightly too small for the disc face but if the pads
are made slightly bigger it wont make a difference to the coverage...

front discs can be the same on various motors

The surface difference between pad and disc is quite noticeable and tbh mate I find it difficult to attribute it to tolerance principles. I would understand it if we were talking a few mm, however this is about 1cm! I can't remember if I've seen anything like this, definitely not on my previous cars. To my eyes this is a design flaw, I'm sure they could have used a different pad or something, even a smaller rotor?

What I'm planing to do is to wire brush the rusty surface and paint it using a heat resistant paint, it's a shame really because had I known that beforehand I would have asked my machinist to make the hub a bit wider in diameter and cut the section of the non needed disc Or maybe this is an opportunity for sourcing some proper calipers?

Anyway, any ideas of which paint product should be used for this application? Thanks.

 

[Yiannis197]

You can get a painted disc and then only the paint where the pad wears will come off, then the rest of the disc will stay coated with the paint

This is a good idea for the future matey, when the rotors will need replacing. Any links mate?? These are 300 x 11 iirc

 

[Mattie]

Where did you get the rear discs made up?

 

[Yiannis197]

My machinist in Greece made them [MENTION=2920]Mattie[/MENTION], he also did a pair for Paul (Proil in here) for his rally car, 3 kgs lighter than stock each. I've got some info in my progress thread should you wish to read.