Disc cracked or just Surface blemish? Help
 

This morning I set about fitting new front pads only to see this on one of the discs....


https://cimg6.ibsrv.net/gimg/www.sco...8535db6697.jpg

I didnt order new discs because they measured about 23.3mm. So I have not opened my new pads and and put the wheel back on. Unfortunately I could not speak to the seller of the pads, and my old discs as they are not open this morning.

The crack/blemish does not run right to the edge of the disc but I am pretty worried about it.

Are these discs scrap ?????

Annoyingly if the discs had been over half worn I was considering upgrading the calipers and discs on my 04 WRX PPP, to Brembo or AP, so if they are scrap I may return the pads and do that. Need to get this sorted soon as it is my daily driver.

As usual a simple job has expanded into a massive PITA grrrrrrrrrrrrr

HI
Can't see the photo clearly when I zoom in , is it just pad staining / deposits or can you clearly see a crack ?

How old are they ?
Have you had any issues with dragging calipers , do the pads all look as though they have worn down the same amount and shape

Cheers Ian

Hi

Thanks for the response.

It isnt deposits as it is not raised to the touch . The discs are about four years old I think, might have to dig out the paperwork to confirm. I thought about pad staining from some of the periods it has stood for a week or so in the damp weather, but the lines are not in the shape of a pad.

I havent had the pads out yet but they look evenly worn, remaining pad is a bit less than the pad metal back.

https://cimg9.ibsrv.net/gimg/www.sco...1e8fc7aa29.jpg

https://cimg3.ibsrv.net/gimg/www.sco...5a186eeb99.jpg


Here are a couple more pics, the thing is when I was looking at it it looked very different from different angles some a lot worse than others, I couldnt feel anything when I rubbed my nail over it, but I imagine you may not feel a hairline crack, especially as the pads are constantly smoothing it over.

Does it show on the other side of disc?

Hi

I idnt have much time today so when I saw the problem I stopped working on it, so I never had the pads out or the discs off unfortunately. I would have thought on a vented disc, even if it was a crack it would not necassarily show through to the other side. But I suppose your point is that if it was pad staining it may well be visible on the other side.

Might have to see if I can get time on it tommorow.

Cheers

from the pic it simply looks like a pad mark BUT the discs look far more worn that your measured spec judging by the inner & outer lip.............

Those discs are a bit past there sell buy date boss I would consider changing anyway.

I thought the lip was big but I repeated the measurement with my micrometer a few times and got about 23.3mm each time, the range is 24 to 22 min. Apparently the grooves dissappear at the lower limit

Ian

Looks like pad deposits to me,but also looks like you could do with a fresh set also.SJ.

Here is a pic of my discs, mot advisory.
 

Piece of mind. Just replace. Don’t be driving around thinking, “what if” Set of new discs with your new pads, then you know everything up front is safe.

Cheers

Dave

As I was not entirely happy with the standard WRX front brakes, I am now considering a big brake kit rather than replacing the discs and pads with standard sized items. I have started a new thread about which kit...