brakes, thickness of disks

[Adi]

Ok, this is for all the clever mechanically minded people, maybe they can help. When doing the brake pad change, how thick should the disk still be? Maybe we can post here for the various models, particularly interetsed myself for the E12 535i(M)

 

[Tumo]

About 5mm, depending on the condition of your disks

 

[freerider]

If you have a bentley or haynes service manual, they will indicate the maximum allowable wear for discs.

 

[Adi]

so below 5mm we change disks?

 

[freerider]

Adi, do you have a brake disc wear measuring caliper?

 

[Tumo]

so below 5mm we change disks?

no you change the pads, if you have less than that left on your brake pads then you are increasing the risk of over wearing or damaging the brake discs. if you have worn discs the pad should be changed more regularly i.e., they will need to be thicker. If your brake disks are very worn then you will need to replace them too

I don't know the exact measurements but this applies to most vehicles. Rather don't take chances

 

[Adi]

Agree fully, looking for the specs so that I can measure, think other people might be ineterested too, as to how thick disks should be...

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got the caliper.........ready to measure!

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interesting part as to how thick they should be when you can still give them a quick skim.....

 

[rick540]

I don't beleive in skimming

1) You remove material that reduces the thermal mass and can cause premature brake fade.

2) You weaken the disc

3) Quality new ones are so cheap from places like Masterparts who sell brands like Febi and Metelli

If the edge has any ridge 3mm or above, or if there is any shudder at all when braking just change the discs, it's good insurance on your life.

 

[Hellas]

Anybody got a pic of a failed disk? I've always heard about the disk breaking, but never seen it.

On the lighter side:

 

[rick540]

I have a few here with cracks, but not ever seen a broken one.

It's quite hard for a ventilated disc to physically break because it's essentially two joined separate discs, but a solid one could easily break.

Saw it on TV once they sort of like explode if you are going fast enough, wouldn't like it to happen to me.

 

[Die_Miek]

About 5mm, depending on the condition of your disks

think 5mm is a "bit" optimistic

did some searching on the net and found for e46's:

318-328:
front thickness new: 22mm
minimum : 20.4mm
rear thickness new: 19mm
minimum : 17.4mm

330:
front thickness new: 25mm
minimum : 23.4mm
rear thickness new: 22mm
minimum : 20mm

cheers