Shelf life for open brake fluid - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

autoracer86 · 06-03-2023, 05:49 PM

Once you crack the seal on brake fluid is it safe to use again after its been sitting for a few months ?

I am looking to bleed my brakes tomorrow and would like to finish off what's left of my castrol SRF plus open another new bottle that I would plan on using again next time I bleed the brakes

any issues with that plan ??

Thanks

Sapphireho · 06-04-2023, 01:55 AM

Quote:

Originally Posted by autoracer86

Once you crack the seal on brake fluid is it safe to use again after its been sitting for a few months ?

I am looking to bleed my brakes tomorrow and would like to finish off what's left of my castrol SRF plus open another new bottle that I would plan on using again next time I bleed the brakes

any issues with that plan ??

Thanks

Probably fine. If you worried about it, pour it into your super clean jar, or measuring cup and look at it. If it looks like vegetable oil, cool. Looks like motor oil, no.

steved · 06-04-2023, 03:34 AM

https://blog.amsoil.com/dot-3-and-do...he-difference/

Mentions dot3 can absorb 2% per year, the more moisture in the brake fluid the lower the boiling point will be. I won't use old bottles myself, especially if it's going on track.

autoracer86 · 06-04-2023, 03:44 AM

Quote:

Originally Posted by steved

https://blog.amsoil.com/dot-3-and-do...he-difference/

Mentions dot3 can absorb 2% per year, the more moisture in the brake fluid the lower the boiling point will be. I won't use old bottles myself, especially if it's going on track.

Hmm the old fluid is not even a year old but I guess some moisture might have got In. I do keep it inside my house rather than outside in a garage if that matters lol

Thanks for the link

autoracer86 · 06-04-2023, 02:44 PM

Okay I used some of the new bottle mixed with the rest of the old bottle. Job done and the brakes feel great. We will see how they hold up long term

Jdmjunkie · 06-04-2023, 03:30 PM

Plastic wrap over top of the opening and then putting the cap on top of that might be an effective moisture barrier.

Teseo · 06-04-2023, 05:02 PM

Put the un-used bottle in your drawer

soundman98 · 06-04-2023, 05:07 PM

Quote:

Originally Posted by Teseo

Put the un-used bottle in your drawer

next to your panties.

villainous_frx · 06-04-2023, 05:52 PM

Quote:

Originally Posted by soundman98

next to your panties.

instructions unclear, everything is in a bunch now.

Grady · 06-08-2023, 08:18 PM

If the cap is tight it can only absorb what moisture is inside the bottle. 2 months 2 years does not make any difference. You will be fine. If you store it outside with the cap off I would not use it.

Sevs753 · 06-08-2023, 09:10 PM

I have a bottle of Stoptech SRF660 fluid that was opened ~4 years ago. Just tested it a few days ago with test strips. The strip barely showed any contamination at all. It probably is at least 98% good. Bottle was sealed with just the regular cap and stored in my garage.

06-03-2023, 05:49 PM	#1
autoracer86 Senior Member Join Date: Jul 2022 Drives: Toyota GT86 Location: Ireland Posts: 686 Thanks: 640 Thanked 511 Times in 318 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Shelf life for open brake fluid Once you crack the seal on brake fluid is it safe to use again after its been sitting for a few months ? I am looking to bleed my brakes tomorrow and would like to finish off what's left of my castrol SRF plus open another new bottle that I would plan on using again next time I bleed the brakes any issues with that plan ?? Thanks __________________ SpareRoomRacing Youtube: https://www.youtube.com/@spareroomracing3168/featured Build Thread: https://www.ft86club.com/forums/showthread.php?t=153004

06-04-2023, 02:44 PM	#5
autoracer86 Senior Member Join Date: Jul 2022 Drives: Toyota GT86 Location: Ireland Posts: 686 Thanks: 640 Thanked 511 Times in 318 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Okay I used some of the new bottle mixed with the rest of the old bottle. Job done and the brakes feel great. We will see how they hold up long term __________________ SpareRoomRacing Youtube: https://www.youtube.com/@spareroomracing3168/featured Build Thread: https://www.ft86club.com/forums/showthread.php?t=153004

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06-04-2023, 03:34 AM	#3
steved Member Join Date: Sep 2018 Drives: 2013 FRS Location: Vancouver, BC Posts: 60 Thanks: 2 Thanked 11 Times in 10 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	https://blog.amsoil.com/dot-3-and-do...he-difference/ Mentions dot3 can absorb 2% per year, the more moisture in the brake fluid the lower the boiling point will be. I won't use old bottles myself, especially if it's going on track.

06-04-2023, 03:30 PM	#6
Jdmjunkie Senior Member Join Date: Apr 2017 Drives: Scion FR-S 10 Series Location: Las Vegas, Nev. Posts: 341 Thanks: 1,840 Thanked 204 Times in 128 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Plastic wrap over top of the opening and then putting the cap on top of that might be an effective moisture barrier.

06-04-2023, 05:02 PM	#7
Teseo Senior Member Join Date: Jun 2014 Drives: frs Location: Gunsai Posts: 4,954 Thanks: 7,467 Thanked 2,980 Times in 1,802 Posts Mentioned: 23 Post(s) Tagged: 2 Thread(s)	Put the un-used bottle in your drawer

06-08-2023, 09:10 PM	#11
Sevs753 Senior Member Join Date: Nov 2012 Drives: BRZ, Canyon Location: Metro Detroit Posts: 453 Thanks: 65 Thanked 136 Times in 86 Posts Mentioned: 1 Post(s) Tagged: 1 Thread(s)	I have a bottle of Stoptech SRF660 fluid that was opened ~4 years ago. Just tested it a few days ago with test strips. The strip barely showed any contamination at all. It probably is at least 98% good. Bottle was sealed with just the regular cap and stored in my garage.

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