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I flushed and bled my brakes last night (for the first time) using the Mityvac method. I did not flush the clutch cylinder due to time constraints. My stupid questions are these: If the master cylinder and all of the brake lines now have new dry fluid in them, wouldn't this eventually circulate into the clutch cylinder? If so, I assume this would partially defeat the purpose of flushing the brakes since some of the old clutch fluid will be mixing with the new fluid, but how much old fluid are we talking about? Isn't a system with 25% old fluid better than one with 100% old fluid?
 

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You'll be fine. Its not that much more work here at the shop when we do a brake flush and bleed the clutch system and 99% of the time we are doing an oil change and have the bottom pan off already. Yes it would be safe to say that 25% old fluid is better that 100% old fluid.
 

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Discussion Starter #3
Thanks for the info. I'll have to PM you later with my VIN so you can tell me when my factory warranty expires.
 

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Unless you put the ABS system through it's paces during the bleed you've left old fluid in that circuit too. :(
 

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My stupid questions are these: If the master cylinder and all of the brake lines now have new dry fluid in them, wouldn't this eventually circulate into the clutch cylinder? If so, I assume this would partially defeat the purpose of flushing the brakes since some of the old clutch fluid will be mixing with the new fluid, but how much old fluid are we talking about? Isn't a system with 25% old fluid better than one with 100% old fluid?
there are no stupid questions except those that are not asked.
we are all here to learn
 

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the clutch hydraulics produce the most contaminants (but not temps) so it could be argued it is very important to flush it.

no idea how much or how long it would take for that to back into the system though, or if it can - don't know if there is a check valve in there???

if you have the time - flush it all - drive it for 15 mins and fire the ABS a bunch, and flush it again....

allways suck out the old resivour fluid prior to flushing.

something is better than nuttin' ...this is true!

i need to do mine!!!
 

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Discussion Starter #8
I appreciate the tips. I'm gonna take Fit's advice and activate the ABS this weekend and flush everything again. Now that I figured out the Mityvac, it shouldn't take as long.
 

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I appreciate the tips. I'm gonna take Fit's advice and activate the ABS this weekend and flush everything again. Now that I figured out the Mityvac, it shouldn't take as long.
I'd ditch the Mityvac for car use and get a Motive. I've got both and use the Mityvac on bikes and the Motive on cars - pressure bleeding is much easier and more foolproof with the cars than vacuum bleeding.

Motive Products
 

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Meh, just change it at regular intervals and it should be fine.

Most of us activate the ABS on a regular enough basis anyway ;) that the fluid won't be trapped in there for very long.
 

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Meh, just change it at regular intervals and it should be fine.

Most of us activate the ABS on a regular enough basis anyway ;) that the fluid won't be trapped in there for very long.
true - however "regular" intervals is a very vauge term depending on usage. less than a year old is a good rule of thumb for track days to not have to worry about issues.

also - perhaps the OP has a situation where there is some rather old fluid that would be good to fully eliminate. the stuff that come out of the clutch is pretty narly....

but you are right that if you are regualrly flushing it while its still "clean" , then you probably do not need to double flush, huhuhu i just said... double flush!
 

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I'd ditch the Mityvac for car use and get a Motive. I've got both and use the Mityvac on bikes and the Motive on cars - pressure bleeding is much easier and more foolproof with the cars than vacuum bleeding.

Motive Products
+1 man i wish i had one back in my rear transaxle alfa days .....
 

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huhuhu i just said... double flush!
related to a courtesy flush?

yearly is a good interval IMO. I used to be a brake mechanic. you'd be shocked how long many cars have had the same fluid in them...or maybe you wouldn't be that shocked:shrug: I was.

I find it necessary to put warnings @ the bottom of my posts made while @ work on a friday - It may not make sense...I'm sorry...my brain is fried and so take all that's said with a grain of salt. or maybe 5 grains.. :D
 

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related to a courtesy flush?

yearly is a good interval IMO. I used to be a brake mechanic. you'd be shocked how long many cars have had the same fluid in them...or maybe you wouldn't be that shocked:shrug: I was.

I find it necessary to put warnings @ the bottom of my posts made while @ work on a friday - It may not make sense...I'm sorry...my brain is fried and so take all that's said with a grain of salt. or maybe 5 grains.. :D
I was surprised (in a good way) that the annual service on my M5 included a full brake system flush (at no charge).
 

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I flush the clutch every few years, and bleed the brakes about every 3-4 track days
And I would like to add that the Motive Pressure bleeder you sell kicks a$$!
 

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I flush the clutch every few years, and bleed the brakes about every 3-4 track days
Keep in mind that the clutch shares the brake fluid (on the Elise and Exige) with the brake system. If you are only flushing the clutch every few years, you are only flushing the brakes every few years.

Take the time to flush the clutch when you flush the brakes...
 

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My Porsche 930 with the G50 hydraulic clutch pedal is much the same, yet the clutch is isolated form the brakes such that the brakes are bled with minimal interaction with the clutch.

That said, the clutch is moderately easy to get to -
 
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