DOT 3 vs DOT 3/4 Brake Fluid

[sfbayjay]

I just installed new rear brake calipers in my '02 XLT and bled the system.

I had one bottle of DOT3 brake fluid I bought for the job, which is what Ford specs for my Explorer.

When I was finished, the brake fluid reservoir was kind of low and I'd used up my bottle of DOT3 fluid. A friend of mine was coming over and stopped at AutoZone to grab some more fluid so I could top off the reservoir.

The fluid from AutoZone is Valvoline "DOT3/4" fluid, which says it's compatible with either DOT3 or DOT4 systems.

Sooo -- can I use this stuff to top off the under-hood reservoir on my system that is full of DOT 3 fluid? Can they be mixed?

 

[techieman33]

Yes you can use it. It is fully compatible with dot 3 fluid. From what I've heard almost no one makes dot 3 fluid anymore they just put dot 4 in the bottle and mark it as dot 3 for those people that are afraid dot 4 will harm their braking system.

 

[M1911A1]

Yes you can use it. It is fully compatible with dot 3 fluid. From what I've heard almost no one makes dot 3 fluid anymore they just put dot 4 in the bottle and mark it as dot 3 for those people that are afraid dot 4 will harm their braking system.

That's right. Also make sure you dispose of the leftover fluid in the bottle. Many people make the mistake of keeping openned containers for future re-fills. That's a no-no since dot3 or 4, will absorb moisture from the air. Many brake systems seals are damage by people re-filling contaminated fluid.