Hi: I really doubt you have a problem with DOT3 fluid. There are very few non-standard fluids (Honda PS an exception)these days, although there are different quality fluids. I suppose you could get the name of the fluid used and check with the manufacturer. DOT-4 has a higher boiling point, which means the brakes won't fade out when they get hot (at least not as quickly). Towing, racing, and driving down Pikes Peak are important heat generators. Still, DOT4 isn't that more expensive. A bleed and flush should allay fears, and your mechanic should do it cheap or free. BTW, ATE, the German brake fluid and hardware people, make fluid in TWO colors (same fluid). The idea is that you can tell when the fluid is completely changed because the color is different. I use Valvoline Semi-synthetic brake fluid, which is fairly cheap and mixes with regular fluid, and is DOT4. If your mechanic charged you a hefty sum he should be willing to do a pressure bleed pretty cheap, since he could have read the specs and done it right. Conclusion, even doing nothing is not a big problem.

I use DOT4 (Castrol LMA) because of the relatively high wet boiling point and it's what Volvo calls for. I would flush it, and be willing to think that no damage was done.

I have never witnessed damage done by DOT3, but there used to be fellows here that said for sure it would damage Girling rubber....I dunno...but you should use DOT4 because it's the brakes we are talking about, and why go against a manufacturer's recommendation, especially in the direction of lower perf?
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http://www.fidalgo.net/~brook4/oilslubesfilters.html

I've used Dot3 for years w/no problem.....if it really bothers you, siphon out the reservoir and fill it w/dot4.the little bit that's left can easily be bled,but IMHO it would be a waste of time unless your volvo is a track car.

I used dot 3 in my bricks for years, until I found out that dot 4 is suppose to be better.

I cant recall having a problem with the dot 3. I use dot 4 now , only because I know its specified .

If you're not planning on entering any drag races in the near future, I would go ahead and run the 3. Then at next flush, use 4.

But its your car, and your time and money. To thine own self, be true.

Good luck

Lawrence

The DOT 3/4 Girling seal BS is a vestigial urban legend that was around long before there even was DOT 4(or a DOT, come to think of it!). DOT 3 will cause no problems, of itself, in your Volvo unless you exceed it's temperature rating, which isn't likely in normal driving. I know people who've put DOT 3 in their 240s for
(10s of)years without even knowing DOT 4 is spec'd.
If you tow or drive aggressively, you'd be better off with DOT 4.

I had always been told by MG gurus to use Castrol GT LMA brake fluid in MG brakes, I think the bottle even says (or used to) something about being suitable for Girling brakes. I would think that if you took it back and the mechanic siphoned out the reservoir and vacuum bled each brake circuit you should be OK.

I'm not sure what kind of problems could occur but I remember an old MG mechanic told me that the rubber bits wouldn't last long if I used the wrong fluid...

Justin B.
83 Turbo