When braking to a stop in my 98 GLT I notice a vibration from the front, sometimes it's more noticable than others. Brake rotors warping perhaps? Or something else to look for?

Most of the time it will be worped rotors.If you are doing upgrades now might be the time for slotted rotors.

Slotted and/or cross drilled rotors aren't the best solution for a daily driver. They're great for track use when they'll be replaced quite often, but slotted and cross-drilled rotors are much more apt to crack.

But someone makes a slightly slotted rotor that is very good.They look light an orbit.They don't warp fast.IPD might sell them but not sure.I see them all the time.

I have used drilled rotors on my Hartge H-3 for years without a problem!! As a matter of fact, several autos now come from the factory with drilled rotors...............Porche is an advocate!! I agree with Tech, if you have any concerns, then slotted is the way to go. I have never heard of an issue with them and they keep the pads clean.
R.

Yes, quite a few cars do come with them from the factory, a lot of cars also come with "Altezza" style tail-lamps as well... just because it's OEM, that doesn't make it right. I'm hesitant to swap the brakes before I switch to 17" rims, since I'll be able to move up to the "big brakes" then. Quick side question: How many pistons are on the stock front calipers?

Well sir...................I have litigated cases for 35 years. From that experience I can assure you that no auto manufacturer is going to expose themselves to liability by knowingly exposing the public to an unsafe product. As I mentioned before, I have used cross drilled rotors in a Hartge h-3 BMW for years with absolutely no issues. The advantages of slotted and drilled rotors are amazing when contrasted to solid or vented rotors! No more fade and no "water shedding" issues to name just two. Now.................if you are going to ignore your brakes until they begin 'squealing'...................then I have no sympathy for you. Before going to jazzy plus one and plus two rims and tyres................improve the safety of your auto and reconcider slotted/cross drilled rotors. May I suggest Brembo.

I'm not saying they're unsafe at all. Just unneccessary on a street-driven S70. As for why I'm hesitant to replace them now, I just bought the car, and as a Marine I don't get paid that well. So replacing something twice in short succession isn't really smart spending.

Oh, I understand what you are saying but truly, cross drilled brakes are fantastic for the casual driver. They shed water and stay cool after repeated stop and go driving. I really believe you would be very happy upgrading to them and saving the tyre/wheel money for a later day. Incidently...............I made $72.00 per month for the two tours I spent in Vietnam. Of course there was a little xtra for 'hazardous duty pay'. All that cash and got the pleasure of being shot....................such a deal! Lock and load...........stay low!

Combat Wounded Myself, Purple Heart Benefits w00t!

I agree with REG there is many benefits with drilled and slotted rotors.Also to answer your other quiestion the front calipers have 1 piston.

Only 1 piston on the front calipers? Are there dual piston or even 4pot calipers from another Volvo that would bolt up?

There is nothing stock that I am aware of that can replace the calipers on your car.You will have to go aftermarket.

Tech, I know where alecw81 is coming from....................I have always enjoyed 4+ piston fixed calipers. But the wave of the future is single piston sliders...............even the hottest BMWs use single piston. Of course I'll bet I know of a Mustang with 4pot calipers..........

I had upgraded to 4piston calipers on my Talon and that thing would stop on a dime. Single Piston seems a bit undersized for a car the size of the S70.

Yes they could have better brakes.But unless you search in junk yards and custom make brackets.You would have to buy a set from an aftermarket company.I understand where you are coming from as well.I am looking for better calipers for my mustang as well.