fitted new rear pads and discs today. pic would explane poor performance as the fronts also show similar tracks on the outer edge of the inside face (all 4 discs affected) but how does this come about...? :-/
http://i344.photobucket.com/albums/p326/chrisgixer/02062009638.jpg


the lumps missing from the disc probably fell away when i belted it with a hammer to brake the seal to the hub. Clearly a risc of falling away at any momment... and are those cracks on the swept area, or is that pattern normal?


But what i find really strange is the 10mill band on the outside edge.  :o can only guess that some pad material has come away( you can see a missing lump in the pad in the correspnding grove) some how and allowed the rest of  the disc to wear while the 10 mill band remained untouched until recently, a judder on the brakes in the last couple of weeks  and a slight improvement in performance in the last couple of days would appear to back this theory up....possible? How could this affect all four discs in an almost  identical way? anyone else seen this?

Cheers

  :-?

never seen something like that..no idea why this happened..

but will effect the brake performance badly, so drive the car slow please until you sort it.. :-/

My front discs looked very similar on the inside surface outer edge, seems to be a common occurance on miggy's .. :(

The "rusty" bits had worn the inside pad down and activated the wear indicator even though the rest of the pads were hardly worn.

I have fitted new discs and pads....  hopefuly they won't go the same way .. :(

they could have put the wrong pads on, i had that with my front discs, pattern pads had been fitted which meant they did not use the whole disc.

Fitted geniune GM all around at the front, massive difference  :y

very very common on cars that have been serviced with cheap pattern pads, and the condition ?by the look of it is a car that has spent a lot of time stood still,

My rear discs looked a lot like that when I changed them

Omegatoy wrote on 02. Jun 2009 at 22:22:

very very common on cars that have been serviced with cheap pattern pads, and the condition ?by the look of it is a car that has spent a lot of time stood still,

:y

If the car is driven regularly and braked regularly the problem does not occur provided the pads are replaced as required.

New discs, new pads then drive the car....   ;)

ah Mr 21, good to hear from you, hope your well?

Thanks for replys Gents.
Rest assured, new discs and pads going on. Picked up parts on Monday and the car flashed up the wear warning the following day  8-). Only one wear sensor on mine.

So what are we saying exactly? That the car has stood for long periods(previous owner. I use if daily) and the discs have rusted causing excess pad wear? Would they "weld" themselves together then rip lumps of pad out when moved? Or just rusty discs is enough on crap pads?

Didnt notice if the old pads where genuine, but the discs had no wording stamped on them as the genuines do....?

Have seen pad marks on other cars discs where the the disc has rusted then leaving a print of the pad on the disc even when the rust is long gone.

Anyway.So nothing too unusual then? My first thought was as Tunnie says, that someones fitted the wrong pads at some point. But then realised that could not be the case as the 10mill area was not being scrubbed, the high area would scrub first when correct size where re fitted, not the low area, the opposite of this....

And by the way, i was considering ebc or similar as a bit of an upgrade, but remembered my old rule about starting from stock with new parts, before condeming the genuine set up. Obviously, having done the rear pads and discs, the improvement  is instant even before they've beefed in fully. Looking forward to getting the front done now :-)

Mine looked like that though not nearly as bad.  It appears as though they delaminate as rust eats beneath the surface.

I removed the raised area (with rust behind) and fitted new pads as the area-loss was not as high as yours.

From the overall corrosion you have, I would have thought it had been exposed to quite a bit of salt.  Winter driving or parked near the sea?

No suspicion of 3rd-party parts on mine.

Very typical for rear brakes especially. In lighter cars with rear discs even worse, because rear brakes do not work that much in every day driving. Here, where we have real winters etc the problem is quite common and big, it's a must to clean and grease the brakes at least annually to avoid this. The caliper gets easily stuck and with only light braking the middle of the pad meets the disc and you can see the results in your pics.

The other marks on your discs are also normal. The small pieces falling off from the outer edge is just corroded steel from disc, not dangerous but you must keep an eye on the minimum disc thickness (which is reached quite quickly due to the facts above)

Looks like the cylinder is putting more presure on the bottom of the dist as the top, when you change them also clean the cylinders might help for even ware.

That chip of material missing from the edge of the disk has been on the move for some time, as the pit it has left behind is rusty.

My guess is that the disk started to break up, there was a crack or even a missing chunk there on the outside edge, and that has abraded away the pad material in that section and prevented it making good contact with the rest of the disk.

That leads to uneven heating of the disk which will only make matters worse.

Any sign what make the disks are as I'm wondering if they are poor quality? Then again, at your mileage they may well be original?

Kevin

I cant see the pictures here (not allowed) but..
I replaced a set of disks and pads recently because the outside edge of the inner surface was badly rusted.
It appeared that the rivet holding the anti-rattle spring was slightly proud of the pad surface, this was bearing directly on the piston rim and caused the pad to sit at a slight angle to the disk. Uneven wear allowed rust to form. Replaced under GM parts warranty.

This seems to be a common problem on replacement Omega disks.

My original set lasted for 40,000 miles, but I have never got more than 15,000 miles from a set since. I have had one set replaced under warranty (after 11 months/9,000 miles), but the Vauxhall Technical Rep reckoned I didn't drive the car enough!  >:(

The front disks on my wife’s Astra have done 65,000 miles, and are in perfect condition (although below the specified minimum thickness).

This suggests to me that the aftermarket disks (i.e. the ones fitted outside of the guarantee period) are not of very good quality.

Edit: I should add, it looks to me as if the outer layer has brokwn up, exposing rough cast iron beneth. I do wonder whether the original disks have a thicker/more durable outer layer than the replacement parts.

Can say mine might have been worse than that when they were changed a couple of weeks ago, on the rear surface that can't be seen. I think also cracks were appearing. And I wondered why the steering wobbled when braking :-[

Mick

This is what mine looked like:

http://www.talkaudio.co.uk/gallery/uploads/8120/CIMG3225.JPG

SMD wrote on 03. Jun 2009 at 19:32:

This is what mine looked like: http://www.talkaudio.co.uk/gallery/uploads/8120/CIMG3225.JPG

Better than my last set then!

NN

well changed front pads and discs earlier tonight and the old ones have exact same wear mark as the fronts above, possibly a tad worse, and mine where genuine gm pads and discs, no doubt about it, gm marked and the numbers are the same except the batch number and a direction arrow on the squeal shim thats not on the new ones.

Ran out of time before i had a chance to check the old rears to see if they are pattern or not.


One more thing, squeal shims on 2 front pads of the four. Which side of the caliper do you fit the shimmed pad? I rang 4 dealers and got a 50/50 decission. I went for piston side in the end. Previous pads where fitted with both shimmed pads on the drivers side! Vx only service history....  numps!

chrisgixer wrote on 03. Jun 2009 at 23:45:

well changed front pads and discs earlier tonight and the old ones have exact same wear mark as the fronts above, possibly a tad worse, and mine where genuine gm pads and discs, no doubt about it, gm marked and the numbers are the same except the batch number and a direction arrow on the squeal shim thats not on the new ones. Ran out of time before i had a chance to check the old rears to see if they are pattern or not. One more thing, squeal shims on 2 front pads of the four. Which side of the caliper do you fit the shimmed pad? I rang 4 dealers and got a 50/50 decission. I went for piston side in the end. Previous pads where fitted with both shimmed pads on the drivers side! Vx only service history....  numps!

well changed front pads and discs earlier tonight and the old ones have exact same wear mark as the fronts above, possibly a tad worse, and mine where genuine gm pads and discs, no doubt about it, gm marked and the numbers are the same except the batch number and a direction arrow on the squeal shim thats not on the new ones.
Those simply look a bad lot of disc castings, even GM  brand will get some lower std batches plus those have really seen some excess heat, maybe  due to harder pads too all adds to overheating causing the metal to get so brittle.

Hi willyboy, how you doing these days? Better i hope?

funny you and others should mention pads, just been reading Entwoods post on his rear pads. He has vented discs all round as i do and found his rear pads low, so then found 2 choices of pads at the dealer, Andy c mentioned the cheaper £14 pads are on trade club and are not oe (but aftermarket so called) but the correct pads for those discs are almost £50 AND ARE NOT ON TRADE CLUB.

Would the cheaper rear pads perform as shown in the pics? The old pads dont have the same print on the back as the new "correct" pads.


So what of the front pads? They ARE on trade club and are the same as what was previously fitted. Does that mean they are of the same quality as the cheaper rears?

Bit of a snake and dagger theory but...?

Does all that make any sense? Its been a long week. :-)