brake disks (rotors)

[Peter Rawlinson]

Waiting for my Haynes manual to arrive, but want to check wear on front disks. anyubody know what min thickness is for front disks on '96 9000CS ECO/LPT?

Thanks,

Pete

[billj]

Welcome to Saabscene, efcbluepete.
Haynes only specifies the minimum thickness after regrind, which is 23.5mm (they start out at 25mm). Presumably, they can be a bit thinner than this (they'll continue to wear after regrinding). Say 22mm at a guess?

Minimum pad thickness is 4mm.

[Peter Rawlinson]

Thanks, will get the verniers out in at lunch time tomorrow(people in work think I'm a bit sad!)

Pete

[sgould]

Not sad, safe!

I have been seen in the office car park measuring my discs with a micrometer

[ms08]

I am going to check mine with a micrometer on my GM900ST when I replace with ATE discs tomorrow - there is a distictive ridge all around the outside of the disc - look very worn to me.

[mark e]

Pete, if you do have ridge round the outside, then obviously verniers won't tell you the correct thickness- you'll need to use a couple of known thickness shims.

[Peter Rawlinson]

just thougt about that this morning, will use the micrometer instead.

Cheers,

Pete

[Derek]

Haynes only specifies the minimum thickness after regrind, which is 23.5mm (they start out at 25mm). Presumably, they can be a bit thinner than this (they'll continue to wear after regrinding). Say 22mm at a guess?[/b]

Haynes further confuses the issue by stating that a max of 1mm can be ground of each side.
The new discs I fitted last week say "Minimum thickness 23mm"

[billj]

Originally posted by Derek:
[qb]Haynes further confuses the issue by stating that a max of 1mm can be ground of each side.[/qb][/b]

I presume that means that you can reduce the total thickness by 1.5mm, but can't take more than 1mm off either face. So 0.75mm off each side would be fine, as would 1mm off one side and 0.5mm off the other. However, 1.25mm off one side and 0.25mm off the other would be a no-no.

I'd forgotten that the discs usually have the minimum thickness stamped on the edge

[Peter Rawlinson]

Hmm, disks fine, pads fine... maybe I'm just used to my wife's 6 month old Honda (very easy to stop). Just feels like I am having to push too hard to stop/slow. Will take advice of other post regarding brake bleeding (wanted to do it today, but no time! Wil probably do it next weekend when I remove the broken exhaust manifold stud I found yesterday.)

Cheers,

Pete

[mark e]

The 9000 is a big old bus to stop... and many report the standard brakes to be not as sharp as they would like.

Changing the fluid will probably help, then you may want to consider a pad upgrade.

[billj]

I've also found many aftermarket discs to perform pretty poorly even with genuine pads. Not all discs are the same. For price/performance, I haven't found anything better than Brembo standard replacements. These are the same as Trent Saab sell with their "Group N" kit, but can be bought much more cheaply elsewhere (I bought the last lot from German & Swedish).

A set is going on my dad's 9000 shortly - I replaced the discs a year ago with cheap aftermarket items and the brakes have been really poor ever since. I should have known better - the same happened with my Aero a couple of years ago.