Determining rotor size on 2004 XC90 Topic is solved

xyourobob · Post by **xyourobob** » 18 May 2017, 11:44

I am going to replace my rotors all around on my 2004 XC90 T6 7 passenger with 18" tires. Can anyone tell me the sure fire method of determining what size my rotors are? The dealer will not tell me.

Post by **joejoethedogfaceboy** » 18 May 2017, 13:58

Had the same trouble on my '04 T5 years ago, and I *think* I ended up with the smaller size. Over at one of the other sites, they said "if you see fins around the hat/center, then you have the larger size". Also, consensus seems to be that T6 with large wheels will have the larger rotors.

Also, try and look for a stamped part number on the "hat" of the rotor, too. I recall that I was able to see one on the OEM rotors on mine. (My XC90 is out on the road at the moment with the daughter, so can't check.)

-Joe

Post by **joejoethedogfaceboy** » 18 May 2017, 13:59

Just noticed you said "all around". My comment was about the front rotors. Didn't realize there could be different sizes on the back, too...

Post by **cn90** » 20 May 2017, 16:57

Get a measurement tape and measure it yourself, that is what I did.

MissFixIt · Post by **MissFixIt** » 20 May 2017, 17:54

I have an 05 2.5 fwd w 18s. My rotors were 308 on the rear, which I believe is universal on all. It is the front that is different. Mine were the larger 336 rotors. You can pull your tire off and measure to be sure. No need to be exact. I think mine were 13.25".

Post by **cn90** » 21 May 2017, 07:51

It depends on what wheel style, mine was a Neptune and I measured the rotor as is, no need to remove the wheels.

I think the post above is correct, the REAR rotor is one size.
The FRONT rotor has a few different sizes.

Post by **Roger_850T** » 25 May 2017, 20:55

I found a reference somewhere that indicated they were matched to the wheel size that originally came on the vehicle. (Don't consider it gospel, but more of a guideline, as it will be incorrect if wheels have been changed.)

FRONT:
18" wheels => 336mm rotors (13.228") OEM 30657301
17" wheels => 328mm rotors (12.914") OEM 31262489
16" wheels => 316mm rotors (12.44")

On mine, I found the Volvo p/n stamped into the outer edge of the rotor, was easy to confirm.
Somewhere, I also recall that all the V8's had the 336mm rotors.

REAR:
I understand only one option for rears, p/n 8624926

The dealer can look it up based on your VIN. (Mine did for me.) If your dealer won't, it sounds like time to find another dealer. (It's not encoded in the VIN, but the dealer can use the VIN to look up the build record, and see what was put on it.)

Roger

Post by **Roger_850T** » 25 May 2017, 20:57

Or, to directly address your question, there are two sure fire ways to check:
1. Measure what's there.
2. Find the part number on what's there.

Roger

xyourobob · Post by **xyourobob** » 29 May 2017, 08:58

Thanks for everybody's feedback. The dealer would not give the part number. I ended up taking the rotors to my local foreign auto parts guy and we just matched them up. Front (316mm)- #30636074 & Rear - #8624926

XC902.5 · Post by **XC902.5** » 24 Jun 2017, 14:54

Hello guys,

The brakes in my xc90 12.44" inch, became rusty and the pads coming to an end, I decided to put the performance brake rotors drilled and slotted . Here in North America, many manufacturers make such a rotors, but according to reviews I read, some brakes is noisy, others rust very quickly, and there are those who have vibration in a week, and even cracks happen.
Considering that the current price of my Volvo is about 1500-2500 cad.
I'm looking for something in the average price range, 200 cad. for 4 rotors, Such prices are on Amazon, If someone of you had a positive experience with the brakes of a similar type, please advise me of a quality manufacturer.

Thanks in advance to the respondent.