purge the brake system

thebigone

thebigone

Joined
May 28, 2011
Messages
132
Location
Newhaven UK
Bike
st 02 & 03
Hi folks, just about to start the strip down of the complete brake system with new parts all round. I was wondering if blowing air through the system to remove the fluid was a good idea, rather than have drips from the diffrent bleed points as I open them ????

regards Chris
 
I wouldn't do that myself. The system was designed or fluid and air might damage seals or something internal. I don't know, I'm just guessing.
 
I do the opposite and use a brake bleeder to vacuum out fluid and a reservoir filler to keep system full while doing this.
 
Explain what new parts your replacing, and why you would need to drain or remove all the fluid to do so.
 
Air will contain moisture, main enemy of brake systems. If you think your fluid is contaminated flush the system(following recommended brake flushing from honda manual.) Then replace parts then re-flush. This will keep fluid in the lines as much as possible.
 
We bleed Air out of the brake system...and you want to Blow air into the brake system? Quick were's my prozac? :well1:
 
Hi may be I should be standing in the naughty boys corner. I was thionking that if the old brake fluid is no good dlow it it and re start with nice fresh after replacing al the piston seals, new pins, rubber boots, new SMC rebuild kit along with rear brake rebuild kit. To be honest I did not think that there might be additional seals and filtters in the lines. From what is being said other than don't do it, I will replace each part in turn and then bleed in a one'er as per the link on here.

PS how long do I have to stand in the corner :(
 
It's an honest question and you got some good replies. No need to stand in the corner, you were brave enough to ask what some have probably done and never asked.. LOL
 
Chris, good question. All the parts were built with air in/around them, so putting air in is not really a worry from that standpoint. However, you're better off having a small amount of old fluid inside the lines (inevitable when performing a standard bleed by the manual) than having a few air bubbles still inside the system because you 'blew' out all the old fluid. Proper bleeding procedure should get all the air out if you 'blew' out the system, but it is dependent on how well the bleeding was done.
:)

FWIW, I wouldn't blow air into my bike's brake system.
 
I gotta' go with blowing the old fluid out with air. If thebigone is rebuilding calipers with news seals, he will have the hydraulic lines disconnected ... which would be an opportune time to blow out old fluid (and any contaminants) before it ever reaches the newly-replaced seals. Though I haven't done this on a bike, I have blown out lines on a couple cars.

In addition to the listed parts being replaced, I would also replace all the flex lines.
 
Last edited:
thebigone said:
Hi may be I should be standing in the naughty boys corner. I was thionking that if the old brake fluid is no good dlow it it and re start with nice fresh after replacing al the piston seals, new pins, rubber boots, new SMC rebuild kit along with rear brake rebuild kit. To be honest I did not think that there might be additional seals and filtters in the lines. From what is being said other than don't do it, I will replace each part in turn and then bleed in a one'er as per the link on here.

PS how long do I have to stand in the corner :(
Click to expand...

Your forgiven...you may return to your seat.
Let us know if you need any help or advice.
The white courtesy phone is available if you need it.
Igofar
 
Mellow said:
It's an honest question and you got some good replies. No need to stand in the corner, you were brave enough to ask what some have probably done and never asked.. LOL
Click to expand...

:plus1:
No such thing as a bad question!
 
Hi,
thanks for all the comments, well I messed up taking my time and putting things down on board and the like, took off all the tupperware to clean thats all hung up. All calipers are off and now clean but I forgot to make surethat the oistons where pushed out:(:( and at the mo about one and half sets look to be stuck. Got work tomorrow Sunday and will be working till late so Monday I will attack them head on.
Another question if I can, on the the rear master cylinder how is the rubber boot removed is it the same type as the SMC
 
thebigone said:
Hi,
thanks for all the comments, well I messed up taking my time and putting things down on board and the like, took off all the tupperware to clean thats all hung up. All calipers are off and now clean but I forgot to make surethat the oistons where pushed out:(:( and at the mo about one and half sets look to be stuck. Got work tomorrow Sunday and will be working till late so Monday I will attack them head on.
Another question if I can, on the the rear master cylinder how is the rubber boot removed is it the same type as the SMC
Click to expand...
The

The white courtesy phone lines are open. PM me your number and I'll call asap to help you with your brake issues.
Igofar
 
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