DOT3 used instead of DOT4

[GNAVECKY]

I topped off the front brake master cylinder (2000 RT with ABS) yesterday, not looking to see what fluid is required. After coming back from a 100 mile ride I looked at the cover on the master cylinder and seen the system required DOT4. I topped it off with DOT3 (about1/2 of the reservoir). Is this going to be a BIG problem? Will the system need to be flushed? Can I do this or do I need to have the dealer do it?

Head up MY BUT

[MANICMECHANIC]

Relax, it's not the end of the world. DOT3 and DOT4 are similar and compatible, but the -4 has a higher boiling point. Personally I wouldn't worry about it, flush at the next service interval. Just my opinion.

[mcmxcivrs]

The DOT 3 may cause problems with the ABS. Nothing that will damage the system, but it propeties are not optimal for the ABS operation. It apparently does not handle the pulsing action of the ABS servo well and can become aerated under extreme ABS braking conditions due to the lower boiling point. Probably would never become an issue, but I'd remove the fluid from the resevior and flush the system with new DOT 4 at the first opportunity.

[GNAVECKY]

Thanks for your replies. I have a service coming up in 900 mile and will flush the system then.

Thanks Again

[rbertalotto]

A thimble full of DOT3 mixed in with DOT4 will do absolutly no harm to your braking system.......DOT3 has a lower boiling point from DOT4 and an ABS system, if ABS is activated, will create more heat than a non ABS system. Don't worry about it.......Stay on your service schedule and change brake fluid at next called for maintenance.......