I am contemplating a brake fluid flush. I think the prescribed fluid for the 98 V70 is DOT4 but is DOT5 safe to use?

Thanks,
Gino

 

Dot-5 is synthetic and will not mix with dot 4. There are pros and cons regarding dot 5. It is very resistant to heat issues for one. It also does not absorb water like dots 3 & 4 BUT, that might be a bad thing because the water in the brake lines will leech out and stay at the lowest point in the brake system potentially causing problems from the inside. Assuming the car came with DOT4 I would stay with dot 4 and religiously flush every couple of years.

 

Regular flushes I plan on keeping up with. Whether there are some components that would be damaged by the DOT5 fluid is my main concern/wonder.

 

I heard/read that dot 5 can adversly affect some rubber components, big but though, I think that mainly has to do with much older cars. You would probably be OK dot5 wise with the Volvo. I'd stick with whatever the car came with and flush. I've also been told you'll get a softer pedal with dot5. Don't understand the reasoning behind this though.

 

Can I top off my XC90 brake fluid with Prestone Dot4 Synthetic. I can't find any Dot4 without Synthetic at AutoZone !