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Brake Fluid

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One of the common questions I asked all riders was for an interval on brake fluid changes. The norm seemed to be every 1-2 years for most road riders. Various intervals were given by track riders and racers like from very regularly to annually.

The follow up question on "How long is a bottle of brake fluid good for once the seal is broken?" again received a common answer of 30 days which is correct.

After 30 seconds of silence, puzzled looks and a little discomfort, the obvious question would come back to me - "Are you saying we should change brake fluid every 30 days?".

It's your bike - you choose.

I change my brake fluid every race weekend on the race bike. My track coaching bike is monthly. My street bike every 90 days. Why so frequently? How much do we depend on our front brakes? Depending on your braking technique the answer is 80-100% for all stopping power.

Rather than take up pages on brake fluid, read this link and come back:

The core of that article looks at native climates and DOT needs and also highlights the key point on brake fluid - dry versus wet boiling points. Do you really want the boiling point dropping by 200F or more with old wet fluid? How's that going to effect your braking distance and stopping performance?

Ever wonder why brakes get mushy after a while? Now you understand why as the brake fluid slowly gets diluted by water coming into the system. Ever seen white crud in the bottom of your master cylinder/reservoir?

If your bike calls for DOT4 on the cap use it. I've tried synthetic and it doesn't work as well so stay away from it on bikes. Way too spongy and no real stopping power compared to conventional fluid. There are all kinds of fluids out there so do some research and see what have the closest and highest dry and wet boiling points. Those products will change annually as new ones are launched, so don't get behind in your research!

That's the first part - the next is splitting the calipers. Many riders think just changing the fluid is enough. It's not - no where near enough. The brake fluid is polluted by brake dust, dirt and debris and water, all sitting inside the calipers growing as goo and sludge all the time. It is critical to split the calipers and pull out all the debris and muck and then polish the brake pistons as well as clean/lube or replace the dust and oil seals. If you have monoblock calipers, you'll need to remove the pistons and then flush the calipers with clean fluid and use lots air to blow all the excess grime and grit out. We wary of using paper towels etc as you may 'lose' some inside the caliper - not a god thing! How often should you do this?

That's right - it's your bike, you choose.

At all the classes I taught during the trip, the one thing I pushed more than anything is "community". Here's a great opportunity to get together and share the work load and cost and get brake fluid changed on multiple bikes at once. gather a group together and rotate the purchaser every 3 months so it all works out $$ wise.

Help each other become more knowledgeable and safer through that knowledge.

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