JohnnyU

Hello,

I'm new but been lurking for sometime now searching for the answer but without success. I have a 2004 Accord V6 with 140K and have not turned or changed rotors. My guess is it's about time (feeling some judder) so I took off the wheels and measured the rotors to be 24mm. My searches on service limit is a little confusing:

2004 ACCORD - Brake disc Specifications

Brake disc Thickness Front (15 inch brake)
New: 22.9-23.1 mm (0.90-0.91 in.)
Service Limit: 21.0 mm (0.83in.)

Brake disc Thickness Front (16 inch brake)
New: 27.9-28.1 mm (1.10-1.11 in.)
Service Limit: 26.0 mm (1.02 in.)

I "assume" that I have the 16 inch as I have the V6 but cannot verify that. When I go to find a replacement rotor at TireRack.com they specify the same Brembo part number (#25549) for V6 as they do for the 4 cylinder. I ordered these Brembos and the thickness out of the box is only 23mm. So my new Brembos are thinner than my OE rotors with 140K miles. What am I missing?

JU

LPED

Hi, first please give as much info on your car .
Like sedan or coupe , AT or MT .
You have 15" if you have AT version, the 16" is on coupe 6MT versions AFAIK .

This parts site has info on sizes, see if it helps .
It says for Auto V6 , normal -23mm , min-21mm and for 6MT V6 , normal -28mm , min-26mm

Brembo 6MT V6 coupe = BR25548

http://www.theautopartsshop.com/sear...s&anoFollow=no

lzyga09

Find a tape measure and see if you have 16 or 15 in rotors. If you have the 16 in I recommend that you get new rotors. If you have the 15in you can bring it to almost any shop and ask them to cut your rotors.Then you can go ahead and throw some new pads on there and your all set. Also you can bleed your breaks if you feel like it. ( bleeding/ flushing is recommended around every 3-5 years depends on the manufacture.)

LPED

That 15" or 16" is not actual rotor size as rotor diameter are around 11.1-11.8 (282-300mm) . The 15/16" reference i think is either wheel size of clearance size of caliper .
Either way measuring it would help to narrow down the right part to be sure .

Targa250R

That's the correct rotor. The Brembo 25549 is equivalent to Honda part numbers 45251-S87-A00 and 45251-TA5-A00. It fits all '03-07 Accord models except for the 2dr EX V6 6-speed, as mentioned above.

If you measured your current rotors at 24mm, then you measured wrong.

JohnnyU

My Accord is a 2004 Sedan V6 automatic. BTW, 16" wheels. Thanks for the reply.

JohnnyU

Thanks for the info. I'm using a digital caliper and it correctly measures the new Brembos at 23mm which is same as they spec. So the caliper is functioning properly. On my OE rotors there is a small lip on the edge that could account for an extra 1 or 2 mm. So let's say there is a 2mm error - that means my used rotors have 22mm. After 140K they are only 1mm less than new Brembos? Something is still not adding up to me.

JohnnyU

Thanks for the replies. I do have 16" wheels if that factors in this. What is "clearance size of caliper" and how is it measured?

redbull-1

Instructions: Using a micrometer, measure disc thickness at eight points, approximately 45° apart and 10 mm (3/8 inch) in from the outer edge of the disc. Replace the brake disc if the smallest measurement is less than the max. refinish limit.

JohnnyU

Thanks, I think your point is that the correct way is to use a micrometer instead of a caliper?

redbull-1

Well, my point is to also measure 10mm away from the edge and with several measurements on the disc to find the smallest measurement.

JohnnyU

Need to print that out and show my wife - justification for new tool.

redbull-1

Lol. I love collecting tools.

LPED

If your using a digital caliper the normal edge that on a rotor will throw off reading (thats why they use micrometer ).
can you take reading of rotor diameter, If your car is all stock it should have the 282mm/11.1 diameter rotors ones, but maybe someone before updated to 6MT 300mm/11.8" ones (I kind of doubt this but who knows )

Accordman1

This info is incorrect. The 15"/16" reference is the size of the brake caliper. The rotor is at least 3" smaller. You would have a 15" brake if your wheel is 16" for clearance. You would have a 16" brake only if your wheel is 17". So the correct rotor for the 15" brake is 11.1" and 16" brake is 11.8".