286-305mm Brake Upgrade

[Dancake]

Thinking of increasing the disc size on my '04 S60 D5. A recent MOT highlighted a 10% reduction in front axle braking efficiency, as well as an increase in the imbalance between the NSF and OSF. The discs and pads are in good condition with at least 6mm material left on the pads, but I'm unsure of brand as they were on the car when I bought it. Car still stops fine but I'd like better efficiency (new calipers also a possibility).

Anyway I was if the 305mm discs would fit under the 16" Mimas alloys, and if the brake hoses need to be changed for longer ones. A quick look online at old threads shows mixed reports. As far as I can tell, the only things that need changed are the caliper carriers (in which case I'll need a set from somewhere). Any opinions/experiences appreciated. Thanks in advance

[cheshired5]

You just need carriers.
Calipers, pads and hoses are all the same.

Just done a video for the 316 upgrade which requires more hardware.
My old 286s were great for my needs so I did it mainly to fill the wheel space and it was always a minor annoyance that the rear disc was larger than the front.
The braking improvement is a bonus really.

286-305 will be excellent too.

[Dancake]

Thought so Chesh, cheers. I'd have considered bigger had my wheels been 17" or above, but the 16" wheels are quite comfortable in comparison to the 17's. Just need to find a set of carriers now

[wynnj]

I've recently bought these from this guy on e-bay to upgrade a 2003 V70 from 286 to 305mm.

http://www.ebay.co.uk/itm/2820850588...%3AMEBIDX%3AIT
http://www.ebay.co.uk/itm/2820850588...%3AMEBIDX%3AIT

The cylinders come complete with the carriers and I checked that they're correct by comparing them after receipt with the carriers on my 08MY S60 which does have 305MM discs.

Confirm with him before hand that what you get is what's in the pictures and you'll get both for just over £20 all in.

I'll stick to my original cylinders but as a bonus I've got got spares now if I have a sticky cylinder in the future.

Hope this helps.
I've no connection with the seller

[reggit]

Here's one to think about - my old s60 had mismatched disks when I bought is, one 286 and one 305mm (turned out it had had a prang , and I suspect the complete strut/hub was changed complete) I didn't notice any imbalance and neither did the MOT man. It only came to light when I fitted 16" wheels with winter tyres for a trip to Germany in December - one didn't clear the disc.

[Jim314]

Fascinating about discovering the mismatch when trying to fit 16" wheels. I could well imagine damage being done before one figured out there was a mismatch, especially if the first front wheel tried had the 286 mm disc, it would go right on and so the job seemed routine . . . until the mismatch on the other side.

What are the details? How did you discover the mismatch?

[bulldogdrummond]

Originally Posted by cheshired5

You just need carriers.
Calipers, pads and hoses are all the same.

Just done a video for the 316 upgrade which requires more hardware.
My old 286s were great for my needs so I did it mainly to fill the wheel space and it was always a minor annoyance that the rear disc was larger than the front.
The braking improvement is a bonus really.

286-305 will be excellent too.

I must be missing something here, how does changing the discs from 286 to 305 but retaining the existing pads and calipers improve braking, surely the actual braking surface is still the same as 286s....perhaps Im just having a bad day??

[Dancake]

According to the research I've done, you need carriers, pads and discs. The hoses and calipers are the same.

[davebb]

Hi The pads are the same
using the 305 and the carriers the pads and the braking part of the disk is more on the out side so there is more braking power,and there is much better cooling on the 305,
Dave

[cheshired5]

Originally Posted by bulldogdrummond

I must be missing something here, how does changing the discs from 286 to 305 but retaining the existing pads and calipers improve braking, surely the actual braking surface is still the same as 286s....perhaps Im just having a bad day??

Cooling and leverage, explained nicely by davebb.