Recent Topics
335i BMW Rear Bearing: DIY?
by antonmnster
25 minutes 21 seconds ago
Noise on cold start
by Spetz
Today at 09:23 PM
FRAM TG4967 C&P
by JohnnyJohnson
Today at 09:10 PM
What is the longest you have had a car battery las
by wtd
Today at 09:00 PM
clicking noise front driver side
by tookien
Today at 08:57 PM
FRAM Ultra XG7317 at 10K miles cut open
by crazy_raccoon
Today at 08:45 PM
Amsoil SS 0w-30 1.4L Tur 2014 Chevy Cruz 20k OCI
by SubieBlue
Today at 08:42 PM
Unknown Found In Woodworking Estate Box
by Recalculating
Today at 07:57 PM
LM-100J (C-130) Airshow
by tom slick
Today at 07:47 PM
Eldora truck race tonight
by thooks
Today at 07:43 PM
Front wheel stud on a 2000 buick century
by JimmyJohns
Today at 07:41 PM
Ford 6.2 diesel
by buck91
Today at 07:34 PM
Weber gas grills & Weber 10 yr warranty
by Donald
Today at 05:50 PM
2008 Honda Odyssey oil and filter?
by CARJ
Today at 05:11 PM
Bugatti Veyron $21k oil change???
by wemay
Today at 05:07 PM
Nexen N Priz AH8 vs Hankook Ventus V2 Concept
by ET16
Today at 04:48 PM
1999 LeSabre to 2008 Lucerne
by Duffyjr
Today at 04:26 PM
Engine Oil "catch cans"
by TnMike46
Today at 04:17 PM
2018 Audi S4 4.5k mi Factory Fill
by Vigg
Today at 03:46 PM
RAGBRAI 2018
by DriveHard
Today at 03:23 PM
Newest Members
99SK04GTX, jasonjossens4231, Eneos1, tung, spacekiller67
65511 Registered Users
Who's Online
57 registered (4WD, antonmnster, Aero540T, aleneros, 87sammy, aquariuscsm, 1 invisible), 1193 Guests and 32 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
65511 Members
67 Forums
287301 Topics
4792837 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Topic Options
#4634825 - 01/14/18 03:57 PM Open Brake Fluid
coopns Offline


Registered: 02/16/05
Posts: 792
Loc: Scituate MA
I opened and used brake fluid container (removed fluid and filled).

Can I use again? I thought I remember someone saying it is (yeah, big word of the day...had to look it up) hygroscopic - absorbs moisture but would that apply even with cap on?
_________________________
Coop

Top
#4634849 - 01/14/18 04:22 PM Re: Open Brake Fluid [Re: coopns]
Trav Offline


Registered: 11/20/06
Posts: 19307
Loc: MA, Mittelfranken.de
Sure you can, put the cap on tight and keep it in a dry cool place, putting it in a ziplock bag is not a bad idea if its going to be longer than a few months.
Unless you live in a very dry climate like southern CA, NM or AZ, etc I would toss it at the 2 year mark.
_________________________
ASE L1, Master. Deutsch Meisterbrief.

Top
#4634865 - 01/14/18 04:40 PM Re: Open Brake Fluid [Re: coopns]
DBMaster Offline


Registered: 09/18/12
Posts: 5340
Loc: DFW
I don't know how accurate the electronic brake fluid moisture detectors are but I tested the fluid in a plastic bottle that had been opened and re-capped for over four years and it still tested as being fine. I've never even thought about it in the past (my pre-BITOG days) and haven't had issues yet.

Top
#4634962 - 01/14/18 06:06 PM Re: Open Brake Fluid [Re: coopns]
slacktide_bitog Offline


Registered: 03/20/08
Posts: 6370
Loc: USA
chuck it, especially if it's a plastic bottle.

If it's a metal can, it will probably be OK.

If you're just using cheap DOT 3, you can get a new bottle of that anywhere. Now if iot was something more premium and expensive, then I could see the point of using the remainder.

Top
#4634975 - 01/14/18 06:20 PM Re: Open Brake Fluid [Re: coopns]
JLawrence08648 Offline


Registered: 01/20/17
Posts: 256
Loc: NJ
Once the cap is off, it pulls moisture from the open space in the bottle. I wouldn't worry about it, it's more important to change your fluid then worry about a little bit of moisture in the air in the bottle.

Top
#4634977 - 01/14/18 06:22 PM Re: Open Brake Fluid [Re: coopns]
bdcardinal Offline


Registered: 06/03/05
Posts: 11078
Loc: Santa Barbara, CA
Even in a low humidity environment unless we are talking a bottle of Castrol SRF, brake fluid is so cheap it isn't worth saving opened bottles.
_________________________
2014 Ford Mustang GT Track Pack
1995 Ford Mustang GT

Ford/Mazda Parts Counter
NRA Benefactor Member
Opinions expressed are my own.

Top
#4635122 - 01/14/18 08:25 PM Re: Open Brake Fluid [Re: coopns]
eljefino Offline


Registered: 06/15/03
Posts: 32774
Loc: ME
A half full bottle in a garage is better than a vented master cylinder in a car driving in weather and seeing heat cycles.

If the fluid's still clear/ amber, run it. At worst use it as a pre-flush when bleeding then finish with something new.

Top
#4635243 - 01/14/18 11:01 PM Re: Open Brake Fluid [Re: coopns]
andyd Offline


Registered: 09/25/04
Posts: 7273
Loc: Marshfield , MA
Wet brake fluid is better than no BF in a pinch, As long as it didn't freeze, it would be fine in a Hydraulic clutch. Also you could squish the bottle until the level was up even and put the top on. I use left over BF to set up airlocks when I bleed.
_________________________
'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2

Top
#4635351 - 01/15/18 04:17 AM Re: Open Brake Fluid [Re: coopns]
Lubener Offline


Registered: 01/22/11
Posts: 2608
Loc: N.Ohio
I have used previously opened (2-3 years) bottles of brake fluid and never had a problem. As long as it is tightly sealed, I wouldn't worry.
_________________________
The "thinking" man's friend.

Top
#4635876 - 01/15/18 03:23 PM Re: Open Brake Fluid [Re: coopns]
barryh Offline


Registered: 01/09/16
Posts: 313
Loc: Cheshire, England
The way I look at it is the fluid in your car is vented to atmosphere via the reservoir cap. The fluid in your bottle or tin is sealed. Which is going to deteriorate quicker ?

The whole thing about throwing unused brake fluid away once opened is ridiculous. If it lasts 2 years in a car that regularly sees 99% relative humidity it's going to last more than 2 years in the tin on the shelf in my dry garage. I would and did choose a tin container over a plastic bottle.
_________________________
Barry

1979 BMW R45 (Triple QX 5W40)
2009 Mercedes C180K (Shell Helix Ultra 5W40)

Top