Is it safe to completely empty the brake fluid reservoir thru a vaccum (Mityvac), then refill it completely with fresh DOT3 Brake Fluid, before proceeding with the Brake Bleeding thru the Mityvac procedure? Thanks.
Emptying brake fluid reservoir?
- Thread starter The Critic
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Yes. I've done this many times.
Take care, Bill
Take care, Bill
Yep, no use flushing all that old fluid through the system. If possible, I like to stick my finger in the resevoir and stir it up a bit before evacuating the fluid. This will stir up any sediment sitting on the bottom so it can be sucked out with the fluid.
I bet his real concern was: can I remove too much fluid from the resevoir and somehow introduce air/dirt into the system.
I betcha!
I betcha!
Your prob correct.
Take every last drop out and put all new in. The big thing is while your bleeding the system, DO NOT let it go dry.. Always keep adding.
Take care, bill
Also, it appears (after a little searching) that DOT 3 is glycol based, and DOT 4 and 5.1 brake fluids contain a borate ester which can all absorb moisture over time (unlike DOT 5). So why not just get it all out of there and put in new fluid? Seems like a good idea to me.
Kestas
Staff member
DOT 3 absorbs water also. A quick and dirty test to identify brake fluid is to mix it in water. Brake fluid will mix readily whereas mineral spirits and oil will not.
Another confirmation...
Suck the old stuff out before you go a flushin'.
I've only bled the brakes on my car one time
but that was the way I did it, and I never have had any trouble. Just make sure you don't get any water or dirt into the reservoir when you are doing it; brake systems are sensitive to contamination.
Suck the old stuff out before you go a flushin'.
I've only bled the brakes on my car one time
It's a great idea to replace the master cyl with fresh fluid before bleeding. Do this a number of times, and it will eventually get clean fluid in the whole sytem without bleeding.
Yeah, I stir to old fluid and suck it out, then replace with fresh before bleeding.
>It's a great idea to replace the master cyl with fresh fluid before bleeding. Do this a number of times, and it will eventually get clean fluid in the whole sytem without bleeding.
The same way you would eventually get clean coolant in the whole cooling system from repeatedly replacing the coolant in the expansion tank. Or you could do the job properly and change all the fluid.
The same way you would eventually get clean coolant in the whole cooling system from repeatedly replacing the coolant in the expansion tank. Or you could do the job properly and change all the fluid.
Kestas
Staff member
I often see shortcuts posted for fluid maintenance -- turkey baster for the ps fluid, drop the trans pan to change the fluid, change the fluid in the master cylinder, and drain the radiator.
I wouldn't change just part of my engine oil, so I don't subscribe to these shortcuts. I do it right or I don't do it at all. But not everyone is willing to go the full mile to perform such maintenance. I wonder how many posters subscribe to these shortcuts but profess to drain every last drop during an engine oil change.
I wouldn't change just part of my engine oil, so I don't subscribe to these shortcuts. I do it right or I don't do it at all. But not everyone is willing to go the full mile to perform such maintenance. I wonder how many posters subscribe to these shortcuts but profess to drain every last drop during an engine oil change.
"Proper" is what works. For very little effort and cost, repeated reservoir fluid changing is well worth it, if anyone chooses to do so.
The same goes for the power steering reservoir.
As a professional mechanic for decades, I know what the options are, and provided an additional, good, alternative.
Changing fluid this way in a cooliing system reservoir is very inefficient, and does not compare, BTW.
The same goes for the power steering reservoir.
As a professional mechanic for decades, I know what the options are, and provided an additional, good, alternative.
Changing fluid this way in a cooliing system reservoir is very inefficient, and does not compare, BTW.
JTK
$100 Site Donor 2025
It's quick, super easy and cheap. It wont hurt a thing & can only help the brake fluid swap.
Joel
Joel
I think some of you are arguing at cross purposes.
Turkey baster/mightyvac alone=near worthless
Turkey baster/mightyvac BEFORE a complete brake flush=great time saver.
Turkey baster/mightyvac alone=near worthless
Turkey baster/mightyvac BEFORE a complete brake flush=great time saver.
I know of people who suck out the master sylinder brake res, all that is doing is giving your res fresh fluid....
what about the fluid in the brake LINES !.,
There is no circulation of fluid in brakes , like in a rad, so I fail to see how this is changing or getting the water out of your system ???????????
do the job right,
engine oil, PS oil, anti freeze they all circulate their fluids, so you can get away with percentage fluid changes,
Brakes need a FLUSH....., !
what about the fluid in the brake LINES !.,
There is no circulation of fluid in brakes , like in a rad, so I fail to see how this is changing or getting the water out of your system ???????????
do the job right,
engine oil, PS oil, anti freeze they all circulate their fluids, so you can get away with percentage fluid changes,
Brakes need a FLUSH....., !
Sure brakes need a flush, but there is no point in pushing the old fluid from the resevoir into the lines when you could drain & refill it with fresh fluid. Then start your bleeding from there... Much better methodology...
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