Reusing new brake fluid | GTAMotorcycle.com

Reusing new brake fluid

bigpoppa

bigpoppa

Well-known member
Just curious, I have more than enough new brake fluid as I install new steel braided lines on the 05 fz6(no abs), can I reuse the new fluid after its been bled, to top up the system as I continue to bleed the lines? (so I dont have to pour fresh from the bottle just to remove some air bubbles?)

Or is this frowned upon?

Thanks
 
I wouldn't. Any junk/dirt/whatever in the lines will be flushed out along with the air during the bleeding process. I wouldn't introduce it back into the system again.
 
You can also get air introduced into the fluid somewhat when you are bleeding. If you are putting it back into the reservoir it might make getting a good lever feel more difficult.

Also brake fluid starts to deteriorate as soon as you open the bottle. you might as well use it up as fast as you can.
 
I don't. Part of it is a practical matter. Once the bottle is open, it is garbage anyway (or will be before the next time I am purging brakes) so I might as well use the new stuff I am going to throw out instead of the lightly used stuff.
 
The problem is dirt contamination.
If it's going into some old POS mud buggy go for it, if it's going on the road :/ not worth the risk.

They tell you to use new from an unopened bottle because of the products hygroscopic nature, the air in a partial full bottle in theory contains moisture that will find its way into the product. That is enough for them to word it as a disclaimer, dirt is considered equally dangerous.
 
No I wouldn't, it only costs a few bucks. I know it probably is inconvienent if you don't have a fresh bottle on hand...but...
 
Quick question, rebuilding the caliper, got the big piston out after some brake cleaner and a tooth brush, but the little piston is stuck, at this rate ill empty the lines/reservoir before the little piston moves, I got new lines that ill be installing, should I use some liquid wrench/penetrating oil?

Trying to pry it out carefully but no luck so far

(got no compressed air or grease gun)
 
Last edited:
bigpoppa said:
Quick question, rebuilding the caliper, got the big piston out after some brake cleaner and a tooth brush, but the little piston is stuck, at this rate ill empty the lines/reservoir before the little piston moves, I got new lines that ill be installing, should I use some liquid wrench/penetrating oil?

Trying to pry it out carefully but no luck so far

(got no compressed air or grease gun)
Click to expand...
Completely stuck it's not moving or moving but won't come out? Next time, block the one that is moving easily and let the fluid pop out the other one.
 
The small one wasn’t budging at all I managed to push it back in just a bit so clearly it’s capable of moving , put the other one back in as well in hopes of being able to force the fluid to push the small one out, but no luck so far


Sent from my iPhone using Tapatalk
 
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I have one of these if you want....
 
As for the expiry date of brake fluid.

I know its not expensive.... but....

say I have some left in a bottle from a previous bike that I did the brakes on this past March 2020.

Will it expire before I want to bleed the brakes on my current bike. I plan on doing them during this coming winter.
 
bigpoppa said:
How well do they work? lol
Click to expand...

I actually bought it after I did the brake job on my previous bike I was selling. I also had a hard time getting those pistons out. (the bike sat for 12 years)

The tool was on sale, inexpensive so I figured I would buy it.

Have not tested it but you are more than willing to try. (without braking the tool or your calipers ) ;)
 
You just want to make sure you do not damage the outside of the pistons.
I bet you are tempted to use a pair of channel locks with some tape on them.
I wouldn't recommend it as the teeth of the channel locks will bite through the tape and most likely leave score marks on the pistons. Which in turn could damage the seals.
 
oioioi said:
You just want to make sure you do not damage the outside of the pistons.
I bet you are tempted to use a pair of channel locks with some tape on them.
I wouldn't recommend it as the teeth of the channel locks will bite through the tape and most likely leave score marks on the pistons. Which in turn could damage the seals.
Click to expand...

Well I got a rebuild kit, new pistons and seals etc but always better to be gentle with the calipers
 
bigpoppa said:
Quick question, rebuilding the caliper, got the big piston out after some brake cleaner and a tooth brush, but the little piston is stuck, at this rate ill empty the lines/reservoir before the little piston moves, I got new lines that ill be installing, should I use some liquid wrench/penetrating oil?

Trying to pry it out carefully but no luck so far

(got no compressed air or grease gun)
Click to expand...
Do you have a great big syringe
... it makes a dandy hydraulic pump,
put the palm of your hand over the big hole and plug off the hydraulic line with your third hand ;)
 
Problem with the FZ6 or Yamaha calipers is that they are one piece. A little difficult to work on there with the limited space.
 
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