DOT 5 brake fluid questions

[RickTheEngineer]

Hey guys, sorry for the couple questions today, but I have just one more thing I needed to ask. I just got done doing some brake line work so I got around to bleeding the brakes today. I noticed that the fluid coming out was yellowish brownish in nature and after bleeding and pumping the brakes for a while, I thought I saw hints of the purple dot 5 coming through as spheres (like mixing oil and water) which makes me concerned on if the truck was switched to dot 3 at some point. I plan to flush the brakes tomorrow by just getting a few bottles of dot 5 and take some time to bleed it all till she bleeds purple. Now for the question. I see some folks say you have to use denatured alcohol throughout, then flush out that with dot 5. Is this necessary? Or will a few bottles of dot 5 be enough to push out all the dot 3 necessary to comfortably "switch" over? Also, do y'all think there was dot 3 in the system after all?

 

[dependable]

DOT 5 also gets clear, amber after a while in the system, it is possible the beeding it is water, as DOT 5 does not absorb moisture the way DOT 3 & 4 do.

It may have been blended and needs to be flushed. If the truck was in local govt service or privately owned, the fluid is is likely to have been mixed.

I would just flush it though to purple, and maybe again after a few drives. The DOT 3 is alcohol based, so if you were going from DOT 5 to DOT 3, an alcohol flush might be in order, but not the other way. Just an opinion though.

Try taking a sample from one of the bleeders and put it in a small amount of new DOT 5. If it does not bead up and separate, maybe your OK.

Of course it is good practice to bleed out the system to clean fluid every few years, regardless of fluid type.

 

[RickTheEngineer]

Alright that sounds like a good plan. I am just going to bleed it until it's onl purple. Personally I think that while using denatured alcohol is the "right way" to do it, I also think seeing as how these two materials don't mix or interact with one another, bleeding to purple might not be so bad. I am going to try to be thorough though, and hopefully it all holds up. I appreciate the input. Sure does help out the cause!

 

[joshuak]

FWIW. If you can remove most of the crud at the bottom and the dirty brake fluid from your MC before you start adding new fluid you'll need to purge less. A basting syringe from a dollar store worked well for me.

 

[Drock]

Unless they changed something again when I wasn't looking , I thought all DOT-5 was purple now? The original DOT-5 was a yellowish color. I would recommend for your sanity replacing all bleeder screws with Russell speed bleeders. Also I found SSBC had good DOT-5 for cheaper then NAPA.

 

[Ilikemtb999]

Unless they changed something again when I wasn't looking , I thought all DOT-5 was purple now? The original DOT-5 was a yellowish color. I would recommend for your sanity replacing all bleeder screws with Russell speed bleeders. Also I found SSBC had good DOT-5 for cheaper then NAPA.

It is, but it'll lose that color over time to a clear/light Amber color. Makes for an easy way to know when you're done flushing.

I I get my dot 5 from advance. You can order online and pick up in store and use an online coupon.