Lipped Discs. Replace?

[blueg33]

The front discs on my A6 are lipped, but I have no brake wear indicator showing. Do I need to replace the discs because they are lipped? Stealer says yes, I am not so sure.

[The Black Flash]

There will be a specified amount of wear which is allowed on the disk (i.e. the depth of the lip). So, it depends how big the lip is.

[blueg33]

The Black Flash said:

There will be a specified amount of wear which is allowed on the disk (i.e. the depth of the lip). So, it depends how big the lip is.

Thanks, the lip is about 1mm maybe 1.2. I need to find out the max and min thickness for the disc, I will ask that in the Audi forum.

[TheEnd]

The lip can be accreted crud and rust and be wider than a new clean disc, so a 1mm lip on each side doesn't necessarily mean 2mm of wear has taken place.

The true way is to measure the actual thickness.

[944fan]

blueg33 said:

The front discs on my A6 are lipped, but I have no brake wear indicator showing. Do I need to replace the discs because they are lipped? Stealer says yes, I am not so sure.

You only get a wear indicator on the pads. The min thickness of the disc is stamped on it somewhere, can't remember if you have to remove the disc to see it though.

Measuring the thickness is hard when it is lipped with a normal vernier gauge because you end up measuring the lip, I use some small pieces of sheet metal of a known thickness as spacers and then substract the thickness of them from the total.

What year is your A6 and do you know which brakes you have, I can check the manual for you for the min thickness if you can't see it on the disc.

[blueg33]

944fan said:

blueg33 said:

The front discs on my A6 are lipped, but I have no brake wear indicator showing. Do I need to replace the discs because they are lipped? Stealer says yes, I am not so sure.

You only get a wear indicator on the pads. The min thickness of the disc is stamped on it somewhere, can't remember if you have to remove the disc to see it though.

Measuring the thickness is hard when it is lipped with a normal vernier gauge because you end up measuring the lip, I use some small pieces of sheet metal of a known thickness as spacers and then substract the thickness of them from the total.

What year is your A6 and do you know which brakes you have, I can check the manual for you for the min thickness if you can't see it on the disc.

I was going to use a micrometer and measure away from the lip.

The car is a 2007 3.0tdi Le Mans Quattro saloon.

It would be great if you can check the manual for me.

[944fan]

There are a number of different types, you will have to check the white sticker in the spare wheel bay to determine which ones you have. You are looking for one of the three character codes below, should be on the second line of codes:

1LT - 23mm Wear Limit
1LD - 28mm Wear Limit
1LG - 28mm Wear Limit
1LH, 1ZL - 28mm Wear Limit
1LJ - 34mm Wear Limit

For future ref the brake pad wear limit is 4mm for all except 1LT which is 3mm.

Cheers

[blueg33]

944fan said:

There are a number of different types, you will have to check the white sticker in the spare wheel bay to determine which ones you have. You are looking for one of the three character codes below, should be on the second line of codes:

1LT - 23mm Wear Limit
1LD - 28mm Wear Limit
1LG - 28mm Wear Limit
1LH, 1ZL - 28mm Wear Limit
1LJ - 34mm Wear Limit

For future ref the brake pad wear limit is 4mm for all except 1LT which is 3mm.

Cheers

Thanks. For clarity on the 1LT for instance is the min thickness 20mm? and 1LD 24mm?

[944fan]

Those figures are the minimum thickness, if less than this then replacement is required.

For example 1LT discs should be 25mm when new and replaced when less than 23mm

ETA: These are from the Audi repair manual, which is probably quite conservative hence they suggest replacing when 2mm of wear has occured.

Edited by 944fan on Thursday 27th January 16:52

[blueg33]

944fan said:

Those figures are the minimum thickness, if less than this then replacement is required.

For example 1LT discs should be 25mm when new and replaced when less than 23mm

ETA: These are from the Audi repair manual, which is probably quite conservative hence they suggest replacing when 2mm of wear has occured.

Edited by 944fan on Thursday 27th January 16:52

Thankis, I read your post again, i misinterpreted it the first time owing to poor multitasking skills