Shelf life for brake fluid
#16
Race Car
Thread Starter
Hmmm
So flushing every 2 years and bleeding before Driver's Ed (2 weekends/year) is sufficient?
I don't actually use my brakes much at Mosport.
Middle run group, signed off, street tires.
They should sell little bottles for the cheapos that only want to bleed a little.
So flushing every 2 years and bleeding before Driver's Ed (2 weekends/year) is sufficient?
I don't actually use my brakes much at Mosport.
Middle run group, signed off, street tires.
They should sell little bottles for the cheapos that only want to bleed a little.
#17
Ate Super Blue is $17 for a full can. The safest thing to do is recycle the old stuff and get a nice new, fresh can.
That said, even tho you are in Ont., if the can is really sealed completely the absorbtion of water vapror cannot physically be greater than the amount of water that is the air space in the can. It won't be much. At 20 oC, and at saturation (100% RH) there will be ~ 17.7 grams of water in 1 m3 of air. The air space in the can is probably about 1/4 litre. The brake fluid remaining in the can is xxx grams. So, do the math -- it is quickly obvious that only an infintesimal amt. is going into the brake fluid -- and that is not at equilibirum, instead it assumes ALL the water goes in from teh air space.
If, OTOH, the can is not sealed, then the water vapor absorbtion will approximate that of the fluid in the reservoir, which is open to the atmosphere.
So don't worry about it.
That said, even tho you are in Ont., if the can is really sealed completely the absorbtion of water vapror cannot physically be greater than the amount of water that is the air space in the can. It won't be much. At 20 oC, and at saturation (100% RH) there will be ~ 17.7 grams of water in 1 m3 of air. The air space in the can is probably about 1/4 litre. The brake fluid remaining in the can is xxx grams. So, do the math -- it is quickly obvious that only an infintesimal amt. is going into the brake fluid -- and that is not at equilibirum, instead it assumes ALL the water goes in from teh air space.
If, OTOH, the can is not sealed, then the water vapor absorbtion will approximate that of the fluid in the reservoir, which is open to the atmosphere.
So don't worry about it.
#18
Burning Brakes
Thank you all for your input on this interesting (to me) topic. Rod 911, please do NOT follow MY advice, as several others (who know far more about these cars than I ever will) have given you their expert opinions (even though experts some times disagree). I agree whole heartedly that the track is not the place to take an unnecessary risk. That being the case, evaluate the points that have been made in this thread and use your best judgement. Logically, I think I fully understand the issues and will do the same. Thanks again everyone!
ps: I would be grand if Super Blue were available smaller, sealed containers (for bleeding) and eliminate the debate altogether
Keith
ps: I would be grand if Super Blue were available smaller, sealed containers (for bleeding) and eliminate the debate altogether
Keith
#19
Addicted Specialist
Rennlist Member
Rennlist Member
Originally Posted by KC911
...would be grand if Super Blue were available smaller, sealed containers (for bleeding) and eliminate the debate altogether
Keith
Keith
I asked a clerk at Costco once why they didn't have a 10-item-or-less Express line. She answered with the question, "you mean so Costco can encourage you to buy only the few items that you actually need?" ...best answer I've had in a long time!
Edward
#21
I never use old brake fluid either. I bite the bullet and buy several small containers so that when I bleed the brakes I can just throw away any unused remainder. I would just top off the reservoir if I were just going to drive it locally and I intended to bleed the system within the next month or so. I definitely would not do it for a track run. I would open a new container and just flush the entire system.
#22
Burning Brakes
Originally Posted by wholberg
I never use old brake fluid either. I bite the bullet and buy several small containers so that when I bleed the brakes I can just throw away any unused remainder. I would just top off the reservoir if I were just going to drive it locally and I intended to bleed the system within the next month or so. I definitely would not do it for a track run. I would open a new container and just flush the entire system.
Keith
#23
Drifting
This is one reason why I like the small Motul 600 cans. Small enough to flush the system, small enough to use the whole can - not big enough where I am tempted to close and reuse at a later date. In the whole scheme of things - why cut corners on something that can potentially so important.
And Keith - check out the wet and dry boiling points of motul 600 - nice numbers compared to ATE.
And Keith - check out the wet and dry boiling points of motul 600 - nice numbers compared to ATE.
#24
Burning Brakes
I will Jeremy, thanks! What's the size of the Motul 600 cans, and where do you get yours from? I'm due for a flush/change, so this thread is timely...
Keith
ps: Since I've got a 1 litre can of ATE on hand, is it OK to mix fluids? i.e. Do the flush/change with ATE (to use it up), and then bleed later with Motul, etc.?
Keith
ps: Since I've got a 1 litre can of ATE on hand, is it OK to mix fluids? i.e. Do the flush/change with ATE (to use it up), and then bleed later with Motul, etc.?
#25
Yeh, bite that $17 bullet.
Motul is hard to find many places -- when I finally found a place in town here that could _order_ the Ate, I thought I was buying a French Burgundy or something. Motul was out of the question...
Motul is hard to find many places -- when I finally found a place in town here that could _order_ the Ate, I thought I was buying a French Burgundy or something. Motul was out of the question...
#28
Burning Brakes
Thanks Jeremy! And Randy, I just checked Pelican, and they have, ATE Gold for 13.00 and ATE Blue for 13.75. I guess I'll just wash my car with the unused brake fluid from now on
Keith
Keith
#30
RL Technical Advisor
Originally Posted by KC911
Steve, You are without a doubt 'the man' (amongst others) when it comes to these cars, but please explain how the partial can (sitting on the shelf for 6 months) is any worse than the fluid that's in the reservoir (that's also exposed to air)? I'm not arguing with your wisdom & experience (that'd be dumb )....I just don't understand. To repeat, I would never use a can of opened fluid for a flush/change, but I just don't see the issue with adding a couple of ounces during a bleed as long as you are flushing & changing to 'new' fluid at the recommended intervals?
Keith
ps: Steve, have you ever used your tester to compare an opened can with the fluid that's in the resevior (from the same can)? I'd be curious....
Keith
ps: Steve, have you ever used your tester to compare an opened can with the fluid that's in the resevior (from the same can)? I'd be curious....
I didn't test a whole range of "aged" fluids in their respective containers, nor did I compare fluid in the reservoir compared to what cam out of the calipers since I was demo'ing this instrument for a short time.
Based on what I've seen in normal coloration changes between the reservoir and what came out of the bleeders, temperature changes exacerbate the absorption rates here. REALLY ignored fluid looks the same (dark brown) whether its in the reserver or in the calipers,....
One should take careful note about the brake fluid recirculating systems that Nextel Cup cars use to push the fluid from the MC to the calipers and back at each pump of the pedal. Its pretty damned ingenious to contain fluid temps in the calipers and allow it to cool off a bit,.....
Just MHO;..........Changing/flushing the brake system at least twice a year for street-only cars and before every track event simply constitutes good preventative maintenance and its a minor cost compared to fuel, oil & tires. For folks on a limited budget I'd suggest getting a few friends together and making a case buy on the fluid of choice to reduce costs here.