RE: Time for a brake flush. What fluid are people using? - 3

Zitat von Mr. 36654 im Beitrag #30

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Try some epoxy resin sometime, that's a hoot to watch froth. You've cycled the system a few times and pulled out more air or other gas.

But where in your brake system are you going to see vacuum pressures in your brake system? So, what has this done for you?

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Zitat von Paul911 im Beitrag #31

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Zitat von Mr. 36654 im Beitrag #30

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Try some epoxy resin sometime, that's a hoot to watch froth. You've cycled the system a few times and pulled out more air or other gas.

But where in your brake system are you going to see vacuum pressures in your brake system? So, what has this done for you?

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Sorry to answer with a question, but where in the brake system is air going to get back into the fluid? To be clear, I'm talking about degassing the fluid before putting it in the brake system.

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Wow. I’m happy when a system flush doesn’t result in any air bubbles in the system. Some of you make a Broadway production about changing the fluid.

Zitat von Mr. 36654 im Beitrag #32

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Where in the system is that dissolved gas going to cause harm or performance degradation?

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Zitat von zer0netgain im Beitrag #33

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Wow. I’m happy when a system flush doesn’t result in any air bubbles in the system. Some of you make a Broadway production about changing the fluid.

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If you have an air compressor in your shop/garage, this is a much easier route than the MightyVac style hand pumps.
https://www.harborfreight.com/brake-fluid-bleeder-92924.html

My Man just changes the fluid. I've never stood and watched him do it.

I've never been disappointed with the brake performance thereafter.

It's half a century since I was pumping and then holding the brake pedal as my dad frequently bled brakes on whatever old car he was running at the time.

I kept my hand in on my first 2 cars, but life then got a bit easier in that department.







ps - did someone suggest that some among us are over thinking it ?

Zitat von Paul911 im Beitrag #36

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Zitat von zer0netgain im Beitrag #33

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Wow. I’m happy when a system flush doesn’t result in any air bubbles in the system. Some of you make a Broadway production about changing the fluid.

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It's really not that much of an extra effort.

https://www.powermotiontech.com/hydrauli...ds-generate-air

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Zitat von basskleff im Beitrag #39

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Good thread, Paul.
My 2016 has low miles- 12.5K, and I had one service done at the local dealer(bums) at 9K.
I'll definitely keep this in mind, as maybe the sitting a lot could up the change interval.

You're in Mass too. Who do you like/trust for when you need service?
Or do you perform nearly all yourself?
Wagner in Worcester where I bought new is generally awful. AJ Cycle on route 2 in Gill has a good reputation.
And it sounds like you like the GS911 diagnostic tool. Enthusiast version?

Cheers

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Thanks for the offer. That's very generous.
I'll keep it in mind!
Chelmsford is not too far. I went to UMass Lowell. Know the area well.
I'm in Boylston, an east-side burb of Worcester right off I-290.
Cheers- Brian

Zitat von Paul911 im Beitrag #35

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Zitat von Mr. 36654 im Beitrag #32

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Where in the system is that dissolved gas going to cause harm or performance degradation?

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My observation on cars has been that it resulted in a firmer pedal feel and less brake fade (two cars autox). Clearly it was far from valid sample set, but does dissolved gas not come out of the fluid at higher temps?

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Zitat von basskleff im Beitrag #39

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Zitat von Paul911 im Beitrag #36

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Zitat von zer0netgain im Beitrag #33

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Wow. I’m happy when a system flush doesn’t result in any air bubbles in the system. Some of you make a Broadway production about changing the fluid.

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It's really not that much of an extra effort.

https://www.powermotiontech.com/hydrauli...ds-generate-air

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Good thread, Paul.
My 2016 has low miles- 12.5K, and I had one service done at the local dealer(bums) at 9K.
I'll definitely keep this in mind, as maybe the sitting a lot could up the change interval.

You're in Mass too. Who do you like/trust for when you need service?
Or do you perform nearly all yourself?
Wagner in Worcester where I bought new is generally awful. AJ Cycle on route 2 in Gill has a good reputation.
And it sounds like you like the GS911 diagnostic tool. Enthusiast version?

Cheers

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Zitat von Mr. 36654 im Beitrag #42

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But, you're assuming it stays out and accumulates. Henry's law says it goes back into solution when the pressure is relieved. While glycol has a larger expansion coefficient than water, you can conceptually understand the 4% change in density between frozen and boiling water. Thus, heating of the brake fluid will tend to increase pressure. I fear you're confusing dissolved gas with water contamination, which lowers the boiling and yields vapor when heated

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Zitat von Paul911 im Beitrag #44

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Zitat von Mr. 36654 im Beitrag #42

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But, you're assuming it stays out and accumulates. Henry's law says it goes back into solution when the pressure is relieved. While glycol has a larger expansion coefficient than water, you can conceptually understand the 4% change in density between frozen and boiling water. Thus, heating of the brake fluid will tend to increase pressure. I fear you're confusing dissolved gas with water contamination, which lowers the boiling and yields vapor when heated

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The brake system is sealed. How would the air get back in?

In a system like that, the brake fluid gets heated and cooled regularly. If the fluid has dissolved gas, heating it will drive out the dissolved gas which will form bubbles. Will those bubbles be reabsorbed at the same rate? Also, when the system is hot, won't those bubbles compress leading to brake fade?

All that said, googling "Henry's law brake fluid" brings up this: https://www.researchgate.net/project/Res...-Braking-System

So apparently someone is/has studied it. I'll request the paper and see if they respond.

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