[rob2006]

Hey folks i'm new here and this is my first post.

I bought a Saab 9-3 Aero nearly 1 month ago its a 2003 with low millage and i have a really serious and dangerous problem with my brakes.

Heres the best description i can provide on my problem....

50mph aproaching a junction, foot on brake, applying pressure like you would with any car > car feels like its stopping then suddenly the braking becomes unbalanced and the ABS seems to kick in. Brakes feel like they are being applied on the right hand side only for a split second then the left hand side then the front left corner and rear right corner, it nearly feels like its going sideways.

The combination off braking can vary from the description above but i hope it gives an idea as to what my car is doing (basically its all over the place when braking). I'm scared to drive past the speed limit so anything slower than me i tend to sit behind for fear off having to touch the brake pedel and ending up in the ditch. Around town is fine and these problems dont seem to exist.

I dont know if this is connected but my cruise control will not work over 60mph and it will not activate in 6th gear at all.

I have just replaced the passenger side lower suspension arm as there was some movement in the balljoint but its made no difference at all. I've had a local garage check it out but they cant find any other worn bushs, play etc in anything.

My discs and pads have aprox 90% life left in them, Tyres are all new Vredesteins.

Please help me.

 

[sgould]

Welcome!

Does it feel as if the ABS is kicking in? Pedal vibrating?

If so, there may be a problem with the ABS sensors or the toothed ring that provides the signal. When this happens on the 9-5, it's often a crack in the toothed ring, or a lump of dirt in it. All this confuses the sensor and makes the brake system think that the wheels are going at different speeds.

The symptoms may be different on the 9-3SS as it has far more electronic intervention in the handling and braking - antilock brakes, traction control, brake force distribution etc.

Some other people have found that the ABS sensors have muck stuck on them, especially metal swarf - even a whole washer! Also check for corroded connections on the sensors or broken wires.

Worth a check before you go to a dealer to get the error codes read. If there's a problem in the electronic control stuff, it can get expensive.

 

[rob2006]

Welcome!

Does it feel as if the ABS is kicking in? Pedal vibrating?

If so, there may be a problem with the ABS sensors or the toothed ring that provides the signal. When this happens on the 9-5, it's often a crack in the toothed ring, or a lump of dirt in it. All this confuses the sensor and makes the brake system think that the wheels are going at different speeds.

The symptoms may be different on the 9-3SS as it has far more electronic intervention in the handling and braking - antilock brakes, traction control, brake force distribution etc.

Some other people have found that the ABS sensors have muck stuck on them, especially metal swarf - even a whole washer! Also check for corroded connections on the sensors or broken wires.

Worth a check before you go to a dealer to get the error codes read. If there's a problem in the electronic control stuff, it can get expensive.[/b]

Yes, the ABS comes in under normal braking conditions at speed. i.e 45mph and above which it should not be doing.

If i give the brakes abuse. i.e i stand on them hard, but not emergency stop hard, the ABS does not activate but the car is squirming from left to right and the braking is VERY uneaven from left to right / front to rear.

My nearest dealer is over 100 miles from me is there no way to read fault codes other than main dealer.? I would have thought a cracked ABS ring or open curcuit in the system would bring up an ABS light or something on the dash.

p.s this forum is weird, why when i look at posts do i only see the first post and have to click on any replys to veiw them.? It makes scaning through a topic very time consuming.

 

[alan6]

A broken ABS ring or dirty sensor will NOT put on the warning light. A broken or bad connection will.
When I had a similar fault with my Ford the garage didn't even need to look at it, said straight away cracked ABS ring and it was.
Alan

Your viewing problem can be sorted by clicking "Options" (right hand end of the post heading band) then chosing the right one of the "Display modes" not sure which one but think it's "Standard"

 

[sgould]

Ah! A problem. The 9-3SS uses a magnetic ring, not a toothed wheel. Still could have a crack in it, I suppose.

 

[rob2006]

Alan6 - thanks thats my viewing problem sorted.

Sgould - that would be what the mechanic was on about then.. when i first contacted them about the problem (via phone) the abs ring was something he mentioned but said it wasn't that when i collected the car as it worked differently. I didnt ask anymore about it.

Is there somewhere on this site that i can get technical drawings etc like the images you posted above.? I'd be happy enought to pull the brakes etc off to check it myself. Do you need to take the hub off to check it.?

 

[quinophex]

The best way to test for this problem is with a diagnostic tool that can read the status of the ABS sensors when you're driving, obviously a TECH-II can do this but no idea for other diagnostic systems. All you do is drive/brake/whatever at the affected speed and watch the wheel speed sensor results to see which one isn't right and you've found your faulty sensor.

 

[aldon]

The best way to test for this problem is with a diagnostic tool that can read the status of the ABS sensors when you're driving, obviously a TECH-II can do this but no idea for other diagnostic systems. All you do is drive/brake/whatever at the affected speed and watch the wheel speed sensor results to see which one isn't right and you've found your faulty sensor.[/b]

OPCOM will read abs speed sensors through a lap top.

If they are faulty, you can't fix/replace them as they are integral to the hub bearing, so the whole lot needs changing.

 

[rob2006]

OPCOM will read abs speed sensors through a lap top.

If they are faulty, you can't fix/replace them as they are integral to the hub bearing, so the whole lot needs changing.[/b]

googled OPCOM. Is it likely that my local vauxhall dealer will have this.?

 

[alan6]

See this thread for OPCOM
http://www.saabscene.com/forum/index.php?showtopic=31650242

Alan

 

[rob2006]

rather than buying a new one does anyone have one they are not using anymore? or anyone out there care to loan me theirs so i can carry out the checks.

 

[sgould]

The pics come from the Saab Workshop Information System and the Electronic Parts Catalogue. There are often DVD's of this sold on the web. Make sure it covers your car and is new enough to cover the year. There's a lot of cheap tat about.

Also there is a Haynes Manual for the 9-3SS.