Do I Need New Front Discs?

[dark andrew]

Hi, I have a 05 Avensis and my front discs are looking fairly worn (i've done about 55,000 miles) but I'm not sure how much more wear I've got left in them. At what point should the discs be replaced? Is there a minimum disc thickness? I can see a line running along the outside edge of the disc at what I guess is about half thickness, is this a wear indicator and if so is this the thickness at which the discs should be replaced?

[Sam29]

Hi, I have a 05 Avensis and my front discs are looking fairly worn (i've done about 55,000 miles) but I'm not sure how much more wear I've got left in them. At what point should the discs be replaced? Is there a minimum disc thickness? I can see a line running along the outside edge of the disc at what I guess is about half thickness, is this a wear indicator and if so is this the thickness at which the discs should be replaced?

According to toyota recommendations:

INSPECT FRONT DISC BRAKE PAD KIT

(a)Using a ruler, measure the disc brake pad lining thickness.

Standard thickness: 12.5 mm (0.492 in.)

Minimum thickness: 2.0 mm (0.079 in.)

Make sure that they have sufficient rebound, no deformation, cracks nor wear, and have had all rust, dirt and foreign particles cleaned off.

INSPECT DISC THICKNESS

(a)Using a micrometer, measure the front disc thickness.

Standard thickness: 26.0 mm (1.024 in.)

Minimum thickness: 24.0 mm (0.945 in.)

Hope it helps.

Cheerio

[dark andrew]

Hi, I have a 05 Avensis and my front discs are looking fairly worn (i've done about 55,000 miles) but I'm not sure how much more wear I've got left in them. At what point should the discs be replaced? Is there a minimum disc thickness? I can see a line running along the outside edge of the disc at what I guess is about half thickness, is this a wear indicator and if so is this the thickness at which the discs should be replaced?

According to toyota recommendations:

INSPECT FRONT DISC BRAKE PAD KIT

(a)Using a ruler, measure the disc brake pad lining thickness.

Standard thickness: 12.5 mm (0.492 in.)

Minimum thickness: 2.0 mm (0.079 in.)

Make sure that they have sufficient rebound, no deformation, cracks nor wear, and have had all rust, dirt and foreign particles cleaned off.

INSPECT DISC THICKNESS

(a)Using a micrometer, measure the front disc thickness.

Standard thickness: 26.0 mm (1.024 in.)

Minimum thickness: 24.0 mm (0.945 in.)

Hope it helps.

Cheerio

Cheers, I'll take that wheel off again and measure it. Now where did I put my micrometer ...

[Sam29]

Have a look at this article

Disc pads troubleshooting

[dark andrew]

Have a look at this article

Disc pads troubleshooting

Thanks for that one, although I've got a bit of a lip on the outside edge of the disc I don't think I'll be sticking it on one of the lathes at work to resurface. Good news - I've found my micrometer, bad news it only extends to 25mm, so I'll have to try to borrow one with a larger opening.

[baba_metca]

You don't need a macrometer - you could use a regular calliper-gauge. Use the stick that measures hole deepness and measure the difference between the lip on the edge and the flat surfice. If you get a reading of about 1.2-1.3mm on the outside of the disk it means that it is time to change them. In my experience the difference on the inside of the disk is less than the difference of the outside. You could tell that just by hand when touching the edge. To be honest you could wait for a bit long, lets say 1.5mm on the outside. But remmember that the thickness of 24mm is preventive - any less is on your risk.

Remember to change the break pads along with the disks, because the old disks have, almost certainly, non perfect shape and using new disk with old pads will probably result in poor break performance, wobbleing, vibration ... all bad stuff