DOT 3 vs. DOT 4?

**scottw** · #1 9 Jul 2004

I've got an '89 R100 GS and I need to top off the brake fluid, but all there is here in Mongolia is some off-brand that says DOT 3. The bike wants DOT 4. Can I use the 3 or do am I out of luck.

Thanks, Scott

**ekaphoto** · #2 9 Jul 2004

I have always been told do not mix brake fluid types ever. If dot 3 is all you have you may want to consider flushing your system and using dot 3 only. Hopefully someone with a lot of technical knowledge will help out.

------------------
John

**Grant Johnson** · #3 9 Jul 2004

Are you SURE you need to top off the fluid?

Usually you never need to - when the fluid is down, it means the pads are just about gone. Unless it's below the minimum level, and the pads are in great shape, leave it. And get some DOT 4 shipped in next time you need pads. You DO change your fluid annually of course, don't you

Mixing 3 and 4 in an emergency shouldn't be a problem - they are essentially compatible - what you CANNOT mix either with is DOT 5. Completely different formulation, also not compatible with most bikes unlkess the manual specifically says it is required..

------------------
Grant Johnson

Seek, and ye shall find.
------------------------

One world, Two wheels.
www.HorizonsUnlimited.com

**Stephano** · #4 15 Jul 2004

Last summer in Jordan we had a brake problem/leak on an F650 GS and could only find DOT 3 (to add to the reservoir on top of DOT 4).

It worked fine and got us back to the UK where everything was sorted out and the fluid was replaced with fresh DOT 4.

Stephan