OK to use old brake fluid?

[wallyuwl]

I am in the process of buying parts for a front brake job. I noticed an unopened probably 5 -6 year old bottle of Valvoline Synpower synthetic brake fluid (Dot 3 and 4) on my shelf.

Is it OK to still use this?

Also, it is a 32 oz bottle. I've never bled brakes before. Is this enough to do a front brake bleed?

If it is not enough, do you see any issues mixing it with a newly bought bottle of blue bottle Valvoline synehetic Dot 3 and 4 brake fluid (as far as I know it is the same as the Synpower product, but I'm not sure - I think they just relabeled the Synpower product to regular Valvoline but am not positive)?

 

[brandini]

NO, it has absorbed water the whole time and the boiling point has dropped. New bottle every time.

I did all 4 corners of my car with a pint you should have plenty.

 

[JHZR2]

the plastic will allow mositure to diffuse in. If it was in a metal can double sealed, Id say maybe. Otherwise, probably not.

That said, lots of folks have had fine braking performance on OE fluid that is sitting in their car for 10+ years. That bottle will likely be better than what was in it. You could use it but plan on doing a flush in a year or so.

But it is cheap enough that Id likely just get a pint of good dot 4.

 

[wallyuwl]

Thanks guys.

Right now it is bulk Dot 3 brake fluid from the last brake job a little under three years ago. The brakes got done at Sears (was living in an appt. at the time so doing them myself was not even an option). So whatever fluid Sears used is what is in there. That fluid currently looks very, very clean, however.

I'm going to put calipers on the front so I think I need to do a front bleed. I'll get some blue bottle Valvoline synthetic Dot 3 and 4 spec fluid.

Will there be an issue mixing this new fluid with the fluid currently in the vehicle (I don't plan to bleed the rear brakes)? Or should I bleed the back ones and have all the same stuff?

 

[Chris Meutsch]

Bleed the whole system if you can.

 

[JHZR2]

Id do all of them. Good practice and many manufacturers recommend it as PM.

 

[MegaCorp]

Brake fluid is good for 5 years, and then it starts to slowly decline. ALthough it would likelt be better than the stuff in your system now.

 

[scurvy]

Originally Posted By: wallyuwl
I am in the process of buying parts for a front brake job. I noticed an unopened probably 5 -6 year old bottle of Valvoline Synpower synthetic brake fluid (Dot 3 and 4) on my shelf.

Is it OK to still use this?

Also, it is a 32 oz bottle. I've never bled brakes before. Is this enough to do a front brake bleed?


If you've never bled the brakes before, I'd absolutely say it's far better than what's in the master cylinder. It's been unopened by you, sealed? Use it up, there's most likely nothing wrong with it.

A quart should be more than enough to do the front brakes, but I would suggest bleeding all the brakes (and clutch slave cylinder, if a three pedal car).

 

[mechtech2]

I'd use it.
Water in it?
I doubt ANY is in there.
32 ounces is enough for a complete bleed.
Suck out your reservoir and fill with fresh, then start your bleed.
Why induce old fluid through the system if you can avoid it?

 

[djb]

I would use it, unless the car was going out to the track for HPDE.

A sealed bottle absorbs relatively little moisture -- it would be bulging if there were any significant moisture intrusion.

The old Synpower fluid was better (higher wet and dry boiling point) than the current Valvoline "3+4" fluid. Even an old bottle of that formula is likely to be better than the current formula.

Now an old bottle of generic DOT-3 fluid.. worthless.

 

[bluestream]

its fine, use it

 

[wallyuwl]

Thanks. I'll keep it and use it. The label on the bottle says 2003, but I can't decypher the printed code on it to tell what date it was actually made. If I had to guess I'd say I probably bought it in 2004 or 2005.

Checked the foil seal and it is in perfect shape. The bottle is not bloated at all. Probably safe to use.

 

[HTSS_TR]

Originally Posted By: JHZR2
the plastic will allow moisture to diffuse in. If it was in a metal can double sealed, Id say maybe. Otherwise, probably not.

That said, lots of folks have had fine braking performance on OE fluid that is sitting in their car for 10+ years. That bottle will likely be better than what was in it. You could use it but plan on doing a flush in a year or so.

But it is cheap enough that Id likely just get a pint of good dot 4.


My friend's 1991 Accord never had brake fluid flush when it sold 2-3 years ago and the brake performs okay.

I would use unopened/sealed brake fluid even it is 5-6 year old, but I would bleed both front and rear.