Brake Fluid Flush
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Joined: Jul 2010
Posts: 59
From: USA
Brake Fluid Flush
So, I found the thread here: https://www.fitfreak.net/forums/fit-...port-auto.html
that shows you pretty much how to do the job. My question is, why is the turkey baster needed? Why not just bleed through the lines and add new fluid as the master reservoir drains down? It just seems redundant to me. I guess you'd want as little old fluid into the system as possible, but it's not like there's gonna be anything in there that can't come out on the other end?
Also, is DOT 4 fluid better than using OEM Honda DOT 3? thanks
that shows you pretty much how to do the job. My question is, why is the turkey baster needed? Why not just bleed through the lines and add new fluid as the master reservoir drains down? It just seems redundant to me. I guess you'd want as little old fluid into the system as possible, but it's not like there's gonna be anything in there that can't come out on the other end?
Also, is DOT 4 fluid better than using OEM Honda DOT 3? thanks
Member
Joined: Mar 2007
Posts: 1,704
From: Second house on the left
Sucking the fluid from the reservoir saves time, that's all. You are going to pump fluid through until it comes out clean at the bleeders, anyway.
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There were some news items a couple years ago about master cylinder failures on Hondas and Toyotas because of some ingredient that the aftermarket brands didn't have. ???
DOT4 has a slightly higher boiling point than DOT3 and supposedly is "Low Moisture Absorbing" ... hence I USED to use it on all my cars. Now I use either the Honda stuff or DOT4.
Never had a problem either way.
++++++++++++
There were some news items a couple years ago about master cylinder failures on Hondas and Toyotas because of some ingredient that the aftermarket brands didn't have. ???
DOT4 has a slightly higher boiling point than DOT3 and supposedly is "Low Moisture Absorbing" ... hence I USED to use it on all my cars. Now I use either the Honda stuff or DOT4.
Never had a problem either way.
Member
Joined: Apr 2012
Posts: 1,095
From: Hebron, In
DOT 4 fluid has a higher WET boiling point than DOT 3. It also will mix with DOT 3 so it does not hurt to change to DOT 4 during a flush.
On a Fit I can not imagine needing DOT 4 because of the size of the car and the size of the brakes. That said, all I use here is DOT 4 and I will put DOT 4 in the Fit when I flush the lines.
The reason for sucking all of the fluid out of the master cylinder reservoir and replacing it with fresh fluid before starting the flush is brake fluid is hygroscopic. Meaning it attracts moisture out of of the air.
When moisture combines with the brake fluid it lowers it's boiling point. So you need fresh fluid in the reservoir when you start pumping it into the system.
On a Fit I can not imagine needing DOT 4 because of the size of the car and the size of the brakes. That said, all I use here is DOT 4 and I will put DOT 4 in the Fit when I flush the lines.
The reason for sucking all of the fluid out of the master cylinder reservoir and replacing it with fresh fluid before starting the flush is brake fluid is hygroscopic. Meaning it attracts moisture out of of the air.
When moisture combines with the brake fluid it lowers it's boiling point. So you need fresh fluid in the reservoir when you start pumping it into the system.
Thread Starter
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Member
Joined: Jul 2010
Posts: 59
From: USA
I know it absorbs moisture and all that, but it's gonna be drained until new fluid comes out of the lines anyway? I can see it taking a bit longer, but if it means one less tool to buy/keep track of, and only a 5-pedal-press difference? thanks
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