Dot 3 or Dot 4?  By  lykos23 (Read 3,427 times)

The difference between dot 3, and dot4 fluids are the boiling point. I would go with dot4, simply because it's less likely to overheat

Thanks, Hank and Sailracer. I'm aware of the difference of the boiling point, just not sure what benefit that is. Will my brake fluid really be subject to boiling point temperatures? I mean, I guess it's possible for a really long stop-n'-go trip, but is this really a problem in the scooter world?

I think I'll go with Dot 4, right in the middle between dot 3 and dot 5. I kind of figured dot 3 was "good enough", but it's better safe than sorry.

I can see why this topic is so seldom discussed as there isn't much to say about brake fluid other than one boils easier than the other, haha.

Lets start with when brake fluid should be changed and the answer is every 2 years max with annually prefered regardless of how it appears. While the fluid may look good in the master cylinder it may be black and corrosive at the wheels. A lot of brake failures are caused by failing to flush and refill the systems with new fluid on a regular schedule.

Once the seal on a can of brake fluid has been broken it really should be disposed of in not all used up in a years time.

When flushing and then refilling a system you should always use a new can of fluid that has the seal intact untill the moment you start the flushing procedure.

For scooters and most other vehicles DOT4 will be preferred over DOT5 which came out for limited use and military vehicles that sit unused for years. DOT5 can be prone to absorbing air causing reduced braking effectiveness. Many will have great difficulty bleeding their brakes with DOT5 especially if they aggitate it which allows air to get incorporated into the fluid.

If your brakes already require a heavy hand to stop then DOT5 may be a very poor choice.

Hi
i like Dot 5 because one of its properties is, it doesn't damage painted finishes
heres some more info
DOT 5 is silicone fluid . Ideally, silicone fluid should be used only to fill non-ABS systems that have not been previously filled with glycol based fluid. Any system that has used glycol based fluid will contain moisture; glycol fluid disperses the moisture throughout the system and contains corrosion inhibitors. Silicone fluid does not allow moisture to enter the system, but does not disperse any that is already there, either. A system filled from dry with silicone fluid does not require the fluid to be changed at intervals, only when the system has been disturbed for a component repair or renewal. The United States armed forces have standardized on silicone brake fluid since the 1990s. Silicone fluid is used extensively in cold climate, particularly in Russia and Finland.
Take care and ride safely
Yours Hank

[replyingto=ryaanlx]ryaanlx[/replyingto]Thanks for the tip, Ryan.

I have some 1/4" fuel line that fits right on the nipple that should work. Then I can get a bottle of sorts to attach to the cap. Then I've got my younger brothers that can help me squeeze the breaks. I should be all set!

I had planned on first bleeding my breaks of all fluid and then switching calipers, then performing the bleeding process again with new fluid with the new calipers so that the new ones get less of the original brake fluid in them.

The brake fluid should have been changed as part of the PDI when you first got the scooter and may have saved you the bother of this repair.

HAHAHA, and here is how to BLEED your brakes all in ONE EASY STEP:

All this and all you have to do is look on the cover of the Reservoir and it will tell you DOT3 or DOT4 take your pick. And may I add how many RIDE THE BRAKE to cause the fluid to start bubbling(HAHAHA).
Alleyoop
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