Silicon DOT 4 VS.DOT 4 Brake fluid!!

[eberlebike4]

Thinking about replacing my DOT 4 Brake fluid with Silicon DOT 4 in my 1988 GL 1500.Good or Bad??Anyone have any experience with silicon Brake fluid in their old wing?

[ct1500]

Silicone based fluid is DOT 5 and must not be mixed with the 4 even in small amounts. If you are completely rebuilding your brake system go for it.

I will stick with what Honda recommends which is 4 and stops my bike reasonably well with a quick and easy flush every couple of years.

Perhaps you are confusing the synthetic 4 fluid which is a marketing ploy as all fluid is synthetic.

[eberlebike4]

Dangit,know i'm going to have to go back to the store and look @ the label again:(....could of sworn it said Silicon 4.....but i'm not going to bet on it:)

[spiralout]

Good write up on brake fluid and the differences by Mike Nixon http://www.motorcycleproject.com/motorc ... fluid.html

[Grasshutperformance]

HD I think used DOT 5. Here is my complaint(s) with it.
First off, regular brake fluid absorbs water, DOT 5 does not. Sounds good, right? Water is heavier than brake fluid. So the water that gets in, condensation, humidity, etc, collects at the lowest point. When you bleed the brakes, the water stays at the low point, by your caliper piston. Yeah, does not sound so nice now. The other thing is while it does not absorb water, it does AIR. Ride to Denver, get up there brakes feel spongy. Bleed them and a little air. Cool, all set, leave Denver get back to normal altitude and spongy again, and again, a little air.
I use DOT 4 fluid and change it every year. Very easy to do, cheap and no issues related to brake fluid.
Tom

[Old Fogey]

HD I think used DOT 5. Here is my complaint(s) with it.
First off, regular brake fluid absorbs water, DOT 5 does not. Sounds good, right? Water is heavier than brake fluid. So the water that gets in, condensation, humidity, etc, collects at the lowest point. When you bleed the brakes, the water stays at the low point, by your caliper piston. Yeah, does not sound so nice now. The other thing is while it does not absorb water, it does AIR. Ride to Denver, get up there brakes feel spongy. Bleed them and a little air. Cool, all set, leave Denver get back to normal altitude and spongy again, and again, a little air.
Tom

All the above are the reasons that the US army, who went for the silicon fluid, are now changing everything back to Dot4 !