Hi guys, just replaced a caliper on my car and used some brake fluid I had stored in my basement, the fluid I believe is a few years old and I'm concerned that this is going to be a problem at some point. I've been reading that the brake fluid container that's been opened goes bad quickly and this being a few years old is now concerning me, what are anyone's thoughts on this? Should I bleed out all the fluid replacing it with new or do you guys think it'll be ok?
Brake Fluid DOT 3
- Thread starter MaximusN8
- Start date
I conferred with our service dog (you said anyone). When I asked what he thought about the condition of your year's old, opened brake fluid stored in the basement, his answer was "rough",...... "rough, rough"
I imagine most here would say "if in doubt, change it out". That's what I would do. You have no idea how much moisture it may have absorbed over those years.
I imagine most here would say "if in doubt, change it out". That's what I would do. You have no idea how much moisture it may have absorbed over those years.
The reason they say to only use fluid from a sealed container is that brake fluid absorbs moisture from the air. It doesn't "go bad" while sitting, but if the container wasn't perfectly sealed after being opened, the fluid won't be perfectly "dry" like a new container would be.
One of the main reasons to change the brake fluid periodically is to "dry out" the fluid. Water gets into the system through condensation, the pores of the rubber seals, and the atmosphere so it's normal for water to gradually build up in the brake system and it's normally not a problem. The fluid can absorb several percent (by volume) of water before it starts to separate out of the solution and cause problems.
Personally, I would not worry about topping off the fluid from a previously opened container of brake fluid as long as it was tightly capped.
One of the main reasons to change the brake fluid periodically is to "dry out" the fluid. Water gets into the system through condensation, the pores of the rubber seals, and the atmosphere so it's normal for water to gradually build up in the brake system and it's normally not a problem. The fluid can absorb several percent (by volume) of water before it starts to separate out of the solution and cause problems.
Personally, I would not worry about topping off the fluid from a previously opened container of brake fluid as long as it was tightly capped.
AutoMechanic
Site Donor 2024
If it was sealed or unopened then there shouldn’t be any issues if the cap was loose or off then I wouldn’t use it. Otherwise you are fine.
A quart of DOT 4 is $5.74 at Walmart 
Brakes feel fine, the container was closed tight!
That's my concern is it may of absorbed moisture. I just don't want any problems with the brake system.
It was closed.
I took it for test drive and it has plenty of braking, the container was used once a couple of years back to top off, I closed the cap right and stored it. I may change all the fluid out next weekend just to be on the safe side!
AutoMechanic
Site Donor 2024
Can’t ever be too safe especially when it comes to brakes.
I agree with that!
If the bottle was open and the seal broken, I would have recycled it and bought new fresh brake fluid. If the bottle was never opened and the seal intact I would have used it.
Closed with foil seal still intact is fine, opened and closed tight but with no foil seal toss it.
