Bit disappointed to note that my rear brake discs are showing signs of wear, not the sort of wear I would expect at approx 22k miles since I fitted them. Genuine parts from my local Saab dealer. The car has done 76,721 miles. Usage maily motorway. The pads are about half worn, but the discs are worn and slightly grooved. Now if this is fair wear for the mileage, then OK but I am now tempted to replace them soon with aftermarket either Brembo or Mintex items, thereby saving me some wonga and hopefully getting just about the same mileage. The fronts, strangely, although now getting worn, are on the same pads and discs as when I bought the car at 51k miles. Boy do the brakes work well - I can get the ABS working on a dry road and that is with Contisport 3 tyres.
Is this on a 9-3 Sport saloon? If so, it seems to be the norm for this car.
Two things cause it, I believe. The increased used of single rear brakes by the stability control system, which is a fairly new thing for those of us with many years experience of typical brake wear from the past.
The other thing is linked. The car has a steering angle sensor and a yaw sensor. If there is any incompatibility between the two items - the steering angle sensor saying that the wheel is turning and the yaw sensor saying the car is going straight - will cause the car to think that there's a skid or instability and this may cause a brake to drag all the time. It could be light dragging which may not wear the pad, but the disc will get very hot and could wear prematurely. And that's before the quality of the steel is considered.
Many thanks for that info. Now it makes sense; the car is a Sportwagon. Also the info seems to confirm why the fronts are not wearing out as quickly as the rears. As said, the brakes are really very good, no complaints about their performance. There is a noticeable ridge on the fronts; as the pads are just over half worn, I am going to keep an eye on them but let them get down a bit more then replace discs and pads as a set. With the rears, similarly I will monitor them, and replace to lot once they have got down a bit more. At this time, the rear pads are about half-worn.
Given the facts regarding how these components wear, esp the rears, any thoughts on using branded (eg Mintex etc) parts? Quite a saving apparently (ie approx £60 for the rear set). I have not yet priced the parts from my local motor factors C R Marks, probably QH origin (ironically, they do supply my local Saab dealer with many service items!)
Thanks again
Pete
The rumour was that the Saab factory 9-3 brake pads were made by Textar. I can't confirm that though, and it probably changed from time to time.
And when I read the WIS last time about this, it stated that the steering angle sensor should be reset (by Tech 2 at a dealer) after any tracking adjustment etc..
Yes that is right the steering angle sensor does have to be reset when tracking or suspension work is done, it is however not just Tech 11 that can be used as I've used different diagnostic equipment to callibrate the angle sensor ;)
While I have not had any tracking adjustments carried out, and the history of the car does not show any steering component changes (eg TREs), it has however had a new pair of front springs and a new R/H front hub bearing assembly. None of these should have affected the geometry, because as far as I can tell, there is no leeway on the top strut mounts or the strut to hub bolts (unlike my lad's Evo which has one of the two bolts each side eccentric) Also I replaced the upper rear arms from an MOT advisory, but there are no steering pulls either way, and tyre wear is perfectly symmetrical both front and rear and shoulders. I will see how it goes once I have replaced all the discs and pads. As my dealer is first-class, I would expect that if there were an issue upon changing the bearing, they would have reset the steering angle sensor?
Since my last post, I have been on several trips including many short runs round Oxford, one trip to LHR, and one today to Milton Keynes. Each time I got home, I checked the rear discs, and they were not hot so hopefully that rules out any problems with the steering angle sensor. There are a couple of scores on both discs which may be down to specks of grit getting in there. I will just accept the wear and replace them fairly soon. Probably do the lot, front and rear, in about 3k miles.
Thanks again all for the guidelines.