Hi,

After buying my 240 I checked over the brake system and changed the brake fluid. I've done this several times with other cars. The car is a 1992. Thinking DOT3 fluid has been the standard for years and DOT4 is a relatively new invention, I put Prestone Synthetic DOT3 fluid in my Volvo. I just bought a Bentley manual and it warns against using DOT3 fluid and to only use DOT4 or risk brake system failure. Have I made a big boo boo? Should I change the fluid out and replace it with DOT4? Has anybody had any problems with this?

Thank you,

Mark

 

I would flush the system really good with the Dot 4.

 

Organic and synthetic fluid are not compatible!!

 

Buck, not 100% true...

Organic (glyptol-based) and SILICONE fluid should never be mixed.

It's confusing because you have DOT 3, DOT 4, DOT 5 (silicone), and DOT 5.1. <SIGH> The debate has flared up on many Lists over the years. Synthetics are becoming more prevalent nowadays but they are still Gylptol.

 

I bled my brakes and put synthetic in to top it off. It sat there never mixing with the organic. I have to draw it off and put in organic and it worked fine.

 

Thanks for the replys. I bought a gallon of DOT4 fluid yesterday. Last night I re-bled the brakes and ran about 3/4 of a quart of DOT4 fluid from the reservoir thru each caliper. Now I have the cleanest brake lines and cylinders on the east coast. I'll keep an eye on it to see what happens. Every car I've ever had uses DOT3. From now on I'll check a book first rather than assume. You know how one can spell assume.

Mark