To be clear, can I be sure my 1996 850R wagon came with the 288mm (11") and not the 302mm (12") rotors? I'm pretty sure but want to be 100% before I buy the 11" pad/rotor kit. And what cars came with the 12 inchers? Thanks!

You can't be 100% sure. I have seen both versions, with R cars leaving the factory with 302 and the "small" 288...From other forums I read that the R actually should have the 302 brake. The 302 brake upgrade was also available from Volvo as an option so it's also possible that in the car history some previous owner fitted the 302 brakes.
The safest method is to go to the car and measure...
Also if you car has 15" rims you definetely have the 288 discs. Columba rims also fit only on 288 discs.

"My point is this: braking, no matter HOW strong, is always going to be limited by your tires."

Better brakes with the same tires will perform better. Better brakes will have a shorter stopping distance with the same tires.

If you can get your abs to engage with your current setup, you'll have the same stopping distance as you would with the best brake system in the world."

ABSOLUTELY NOT !!!!!!!!!!!
TESTED, MEASURED ...... proven wrong. Not "IMHO", fact.
The time between an ABS releasing and reapplying in a given situation won't vary but the time the pads take to grip the rotors is a variable depending on quality of both brake pad and rotor surface. Better pads and or rotor surface condition will affect the ability and time to re-apply. It will also vary depending on how the rotor and pad can handle the heat that builds up each cycle the caliper reapplies pressure.

Better pads or quality of rotor = proven, measured shorter braking distance.

ABS does not care what condition the road is in. It can be dry, smooth, icy, sandy, covered in oil or Teflon and the ABS if working properly will function the same on all surfaces, exactly the same on all surfaces.

ABS only looks at wheel lockup. It's a comparative system that uses signals from each wheel in the best systems but sometimes the signal is taken from a shaft or transmission.

All the ABS does is keeps the wheels from locking up so you retain the ability to steer. That is if you're not like a deer in the headlights with a death grip on the steering wheel and something getting bigger and bigger, closer and closer out the windshield that you're centered on :eek: , you have a chance to steer around it.

Now having said that the calipers if under the ABS control are grabbing and releasing the discs rapidly and this is where the difference between 14.95 brake pads and 25 to 60 dollar ones come into play.

It's a researched and tested fact that the cheep pads will stop your car. They will also lock up the rotors without any problem so a lot of non-thinking folks think they are just as good as the expensive pads, just maybe don't last as long. They are right, they don't last as long. They're cheap for a reason.

In ABS mode good pads will re-apply and grab faster and surer (less fade) than the cheap ones. They tested them and in an ABS car when you hammer on the brakes and come skidding to a stop the extra money you spend on the next better pads works out to a shorter stopping distance. If 5 or 10 feet would keep you from hitting something that next better brake pad would be your better choice.

If you are going to be replacing your rotors anyway going to 70 series 302's is a no brainier as all you're paying extra for is the caliper mounting brackets. $100 to $150 depending on who you can find for a source.
You should replace the hoses with longer ones but I've seen a number of people say they didn't and haven't had any problems.

Are 302's better, ABSOLUTELY.
Do you need them ... not on a daily driver unless you have a lead foot or a 17/18 year old.
Should you consider them, if you're upgrading anything on the engine you should be considering upgrading how you stop it.
Where they come in handy is if you find yourself in a situation where you are doing multiple hard stops with little time in between to cool down.
Good tires are also something to think of if the last time rubber went on your vehicle price was the main consideration.
Same with the suspension, so you can control it.

I'm running 302's, frozen and slotted.

Cool thanks. I'll get out there and measure and report back. Hopefully it has 302s.

You're entitled to your opinion. What engineering school did you go to?

Friction between tires and road is < friction between stock brakes and rotors. Translation: tires will slip before brakes will. Simple math, really.

Why a Big Brake Kit Won't Make Your Car Stop Faster - Autos.com

http://www.stoptech.com/docs/media-c...raking-systems

Brake Myth #1

http://www.cquence.net/blog/big-brak...-do-they-work/

A little more accurate info than you will get from the ricer forums and from most manufacturers.

Also, A point that i forgot to mention: larger brakes weigh more. More unsprung weight CAN hurt stopping distances, and can shorten the life of your suspension components.


Additionally, cryo-treating is a waste of money and a marketing gimmick.

Well, I know I had some cheep pads on the car when I experienced my scary brake fade.

I know under extream lock-up circumstances that the rubber on the road will make some difference, but mainly I believe the pad and matal meterial will matter most.

Day to day driving, my daughter's S70 has better brakes than my '95 R. It takes less effort to stop that car and it may stop shorter and has stock tires (I have not tested this). I have 215/45-17's while the S70 has 195/55-15's. I think my car has Volvo pads while her car has Akebono pads.

Upgraded calipers and rotors in a big brake kit will result in more braking torque, the stopping force applied to the wheels. This will bring about wheel lockup or ABS intervention sooner than with the stock system. This should not be interpreted as a shorter stopping distance. In many instances the larger brakes confuse the stock ABS system which is not tuned to the different pressures required to engage and disengage the brakes.

So they're speculating that the ABS system might become confused and increase stopping distances, or that earlier wheel lock up or ABS intervention will lead to longer stopping distances (assuming the wheels lock up). Interesting concept but would this really be a factor in an 11" v. 12" system? My best guess is you wouldn't get shorter stopping distances or longer ones. It would be about the same.

Big brake systems were not designed to stop your car sooner, but rather, stop it more efficiently and consistently. The larger calipers, vented discs, and exotic-compound pads increase heat capacity and heat dissipation. These upgraded braking systems not only perform well under extreme temperatures, but in most cases perform better when hot as opposed to average street driving temperatures.

This makes total sense to me. And since my wagon isn't going to be a track car, the bigger brake kit is an unnecessary expense, especially given the $300+ I'd incur paying a mechanic to replace the brake lines.

I think I've decided that I'm just going to put back on the same size that's on there now. If it came with 302mm's, that's what's going on. If it came with 288mm's, then that's what's going on.

Another thing that those articles I posted may or may not have addressed is that when you change your front brakes to a big brake kit, your brake bias gets screwed up. that's never good either.

Probably a good choice to save your money and stick with stock. That being said, I definitely see the benefit of a bbk if you're autocrossing or racing. Otherwise, yeah, not so much.

There is a lot of technical info flying and I'm not talking about going to a near or full race system.
Really big brakes, there is a place for them, there are concerns also but the OP asked if the 302/305 upgrade was worth it.

I'm saying that going with the Volvo, factory available option of 302 or 305mm rotors that came stock on European 850 police cars is safe, stops better and more reliably than the smaller 280mm rotors most of our cars came with and was designed by Volvo specifically for 850s.

The other thing is better quality pads. Tires are the ultimate limiting factor in stopping distance. I am in no way disputing that. My point is that just because a pad will lock the wheel from turning doesn't prove they are all the same or they all do it repeatedly as well.

Two cars, exact in everything except one has cheap brake pads and one has really good quality pads.
No ABS, first stop (brakes cool), slam on the brakes, stopping distance should be exactly the same.
Limiting factor is tires.
ABS, first stop, slam on the brakes and the better quality pads will engage the rotors a bit faster (millisecond) due to their better friction qualities and in doing so will cycle under ABS control sooner. The pulsing cycle of the ABS is faster and leads to a shorter stopping distance because the better pad has an improved amount of friction and handles the heat better.
Limiting factor tires but also how quickly the ABS can cycle.

Not my opinion and not from a nameless article from a website who's main purpose is supplying a search engine for new and used vehicle hunting.
I'm going off automotive trade publications like "Brake and Suspension", "Automotive engineering" and others. Not using manufacturers fluff, not my seat of the pants faux engineering advise.

Best thing to do is leave it open to people who have it.
Or ask over on VolvoSpeed and see what they say.

Anyone have it and wished they hadn't done it or switched back ??

Anyone have the upgrade and have a problem with front/rear bias or ABS function ??

The other side of that coin is how many people with stock 280mm rotors have been in a situation where they wished they had a bit more "brake" or have had fade, besides RSPI ??
He's a firm believer in "drive it like you stole it" ;)

Hey, as I said, you're entitled to your belief, but all the articles (along with the laws of physics) I posted happen to disagree with you. Of COURSE people who have done it want to say that their stopping distances improved by 30% or whatever....they don't want to believe that they bought that big brake kit for nothing. real world testing not paid for by a company trying to sell you big brakes bears that out. Hell, even the stoptech article basically stated that a bigger brake kit will not improve your stopping distance.

also, whether or not they know it, EVERYONE who switched to a big brake kit has an issue with brake bias. Again, simple physics bears that out. I encourage you to go back to the stoptech article I posted and read under "Effects of Weight Transfer on Tire Output" and follow the mathematics shown.

I could make the same argument about the tornado air intake system: the thing that supposedly "spins" the air to give you more power. They, of course, dont work, but if you ask people who have it, they'l rave about the power it gave them. Why? because they dont want to admit to themselves or anyone else that they got suckered.

Ok I measured them. I have the 11" (288mm) discs on my 1996 850R wagon. I think I'm going to get this kit...

Volvo Brake Kit (Brembo Rotors Akebono Pads) 288MMBK4 | FCP Euro

The also make one with the PBR pads but I've heard a lot of good things about the Akebono pads in my research.

Akebono makes a good pad. I'd run Akebono or Hawk, personally. And the brembo rotors are good quality.

Wow! I had no idea how many had posted to this thread. I'm updating the first post with part prices.

For how cheap it is to upgrade the front rotors to 302mm, I'm shocked people are debating the cost.

Yes, It has made a big difference in my daily braking ;)

Did you change the lines, and what a difference in stopping ability did you note?

I just updated my first post on this subject and "yes" it was a nightmare to replace the front brake hoses. To loosen the front brake hoses, I had to applying heat and using a dedicated brake line wrench ;)

It make a huge difference in stopping power but I believe the issue I was experiencing could have been resolved with upgrading the brake pads first.

Yes, I suspect mine has cheap pads on it as well as worn rotors. My car's prior owners did everything else on the cheap so why not this? A lot of these cars might be in this boat. I think changing the pads and rotors alone will amount to a big improvement. I don't want to change the lines for the reasons you descibed.

Start by:
1. Purchase high quality brake pads
2. Have your rotors turned. Most places will turn them for $10 each if not less
3. Flush your brake fluid

Please be aware, the factory rubber brake lines require replacement just like your timing belt. When I replaced mine, I was shocked to see all the cracks in the hoses :eek:

You should be doing a complete flush on your brake fluid every 2 years. That's gonna make a difference in how your braking feels, as are new brake lines. Much more so than changing the size of your rotor will.

How do you flush your brake system?

Do you just crack the bleeders open, and fill with fresh brake fluid while the old is coming out the bleeders? Does it use a solvent of some sort, or ?