Silicone DOT 5 brake fluid.

[KEITH KRAUSE]

My new '79 GS1000E came with glycol (DOT3) brake fluid.
After 1 year I replaced it with (DOT 5) silicone fluid and after 23 years I thought I should post this recommendation.
The advantages of silicone are, it does'nt attract moisture like glycol, so there's less chance for corrosion of the metal parts.
It has a higher boiling point (510 degrees) than glycol (450 degrees.)Again, less chance for moisture in the system. The extra 60 degrees is more protection.
Silicone helps the rubber parts in the system to last longer.
Silicone won't damage your paint like glycol.
Silicone apparently has a longer service life than glycol. I don't have a specific maintenance schedule for silicone, but the mechanics/people I've known, say they can change their fluid less often and when they do, the old fluid is much cleaner. I've only changed mine about 4 times and each time the fluid looked good, almost like I was just throwing out perfectly good fluid? When I changed out the original glycol, I noticed a large glob of water floating in the rear master cylinder and both the front and rear systems had a lot of contaminants in the fluid. This was on a 1 year old bike!
The only disadvantage to silicone is the price. About $8 for each 12oz. bottle. The glycol is about $3 each. However, the ability of the silicone to last longer because it stays cleaner helps make up for the extra cost. You also have more free time.
If you decide to try silicone fluid, COMPLETELY FLUSH all the old glycol out first. Silicone and glycol do not mix!

[Anonymous]

And if you get any silicone brake fluid on your paint (cars mostly) it will NOT hurt the finish. One of my favorite characteristics

[Mr. Jiggles]

KK - What did you flush the glycol out with?? I plan on upgrading to stainless braided lines soon and hope to make the switch to silicon while I'm at it.

Thanks,

Jeff

[KEITH KRAUSE]

I completely took apart the entire system. You would be surprised how much contaminants can hide in the calipers that typical bleeding procedures may not flush out. Popping the pistons out with compressed air was easy, but I remember installing their new seals was a real learning experience, at least on my '79 GS1000E. The factory manual was no help and I tried 3 times before they sealed right. There was a certain trick to doing it that I cannot remember now. That is the only problem I had by taking apart the entire system. I also replaced the caliper axle o-rings and re-greased the axles. I think this is the best way to do the job. Clean everything up with contact cleaner or brake cleaner and dry. I have SS lines too, from Russell. Also the Speedbleeders.
If you don't want to take the calipers apart(and I don't blame you) you can always just remove the bleed screws(if they are'nt stuck) and dump the old fluid out and rinse/spray the insides with brake cleaner and dry. Don't use something like carb spray, it's bad for the rubber seals. Clean up your master cylinder real good and (along with your new lines) you should have a clean/dry system to re-fill.
If you're real lazy and just want to pump in the new fluid to force the old out, be prepared to buy more silicone fluid than you would normally need.