I have read that generally speaking, discs will last about the life of two sets of pads. My C70 is approaching 33,000 miles and needs new pads, but I'm wondering about the discs. I'm assuming they cannot be worn enough to need replacing already, but what the heck do I know. Two questions:
1) Most worn discs on cars have a ridge along the outer edge and near the inside where the brake pads do not rub. In other words, the brake pads eventually wear a "valley" in the disc. But, I beleive, a brand new disc is usually flat along it's whole surface - i.e., no ridges or valley. My C70 discs have a fairly pronounced "valley" and ridges, more than I can believe could be created in 33,000 miles. Are brand new C70 discs smooth on the whole surface, or do they come with a valley already in them?
2) Assuming some degree of valley is present (and thus an outer ridge is present), how do you measure the disc thickness to see if it is still withing spec? I have a caliper, but it has flat jaws, and thus can only measure the outer ridge. What is normally used?
Brake Disc Thickness?
Started by
Guest_Guest_DouginDenver_*_*
, Feb 21 2005 09:29 PM
1 reply to this topic
#1 Guest_Guest_DouginDenver_*_*
Guest_Guest_DouginDenver_*_*
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Posted 21 February 2005 - 09:29 PM
#2
Bay13
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Posted 22 February 2005 - 12:23 AM
What is normally used is a brake disc caliper, it has a point on one side instead of the two flat sides. You might be able to get a rough est. with your calipers.
The specs for your rotors
Thickness new 26mm
Must be replaced at 23mm
Minimum thickness at pad replacement is 23.8mm
The rotors do not come with a ridge, they are flat, the ridge you have is from the pads wearing out the rotor.
The Pocket Data booklet is part number TP0302207 runs about $20-25 dollars and is full of all kinds of information about your car. The above part number is for 1991-1998 S/V/C70, 850s, S90, V90, 900, 700s.
The specs for your rotors
Thickness new 26mm
Must be replaced at 23mm
Minimum thickness at pad replacement is 23.8mm
The rotors do not come with a ridge, they are flat, the ridge you have is from the pads wearing out the rotor.
The Pocket Data booklet is part number TP0302207 runs about $20-25 dollars and is full of all kinds of information about your car. The above part number is for 1991-1998 S/V/C70, 850s, S90, V90, 900, 700s.
