Why you should flush your brake fluid properly

[Jetfixer]

Here's a good read on brake fluid:

https://www.g-locbrakes.com/products/brake-fluid/

[bigbadbrucie]

Good info to know.What next for us.................... magnetics???

Don’t discount anything.....who the ach eee double hockey sticks knows?

[McRuss]

With that being said, I have been told that the fluid is replaced on a police vehicle after it has been involved in a prolonged high speed pursuit.

Hmm, maybe now.....During my 23 years as a LEO, and many high speed pursuits, as well as high speed non-pursuits (getting to an emergency for example), I never heard of replacing the brake fluid. I will say that this was about the time disk brakes were being introduced to cars. Maybe drum brakes were different. I will also say that the old drum brakes would fade pretty fast, making for some interesting stopping!

[Jetfixer]

Here's the latest one I've done. This is from a 2021 F3L with 17k miles that is almost exactly 2 years old.

20230407_130538.jpg

[FrogmanDave]

Here's the latest one I've done. This is from a 2021 F3L with 17k miles that is almost exactly 2 years old.

20230407_130538.jpg

That is crazy dark for being just 2 years old. Very surprising indeed.

[seaweed]

Here's the latest one I've done. This is from a 2021 F3L with 17k miles that is almost exactly 2 years old.

20230407_130538.jpg

Crap that is a lot of crap in the brake-fluid.

[UtahPete]

Here's the latest one I've done. This is from a 2021 F3L with 17k miles that is almost exactly 2 years old.

20230407_130538.jpg

I'm seeing discoloration but not necessarily contamination. Is that right?

[Peter Aawen]

I'm seeing discoloration but not necessarily contamination. Is that right?

The 'discoloration' IS contamination!

It's all the moisture/water absorbed into the brake fluid that's making it change colour. The darker the colour, the thicker the fluid; the more moisture/contamination present....

[FrogmanDave]

The 'discoloration' IS contamination!

It's all the moisture/water absorbed into the brake fluid that's making it change colour. The darker the colour, the thicker the fluid; the more moisture/contamination present....

Exactly right!

[Freddy]

The 'discoloration' IS contamination!

It's all the moisture/water absorbed into the brake fluid that's making it change colour. The darker the colour, the thicker the fluid; the more moisture/contamination present....

Pure conjecture. Get a brake fluid moisture tester to measure it correctly. See reply 9. Take the guess work out of it.

[Peter Aawen]

Pure conjecture. Get a brake fluid moisture tester to measure it correctly. See reply 9. Take the guess work out of it.

If the brake fluid never gets any moisture in it, Freddy, and there's no existing contamination &/or rust in the brake lines, then unless you cook the brakes well & truly, the brake fluid won't ever change colour - but you ARE right if you want to take the guess work out of finding out HOW MUCH moisture is in it; the only way to properly do that is with a moisture tester..... or with a whole bunch of fairly expensive laboratory equipment so that you can actually boil the water out, catch it as steam, re-condense it, and measure it!

For my 2 bob's worth, even if it's not time to change the brake fluid as per the maintenance schedule, if you've got discoloured brake fluid, then it HAS GOT moisture in it and your braking won't be as good as it could/should be, especially if you ever get the brakes hot, so I'd swap it out even without knowing exactly how much moisture is in there.... Hang on, that IS exactly what I do!

[Freddy]

I put the prongs of my little tester in the reservoirs once in a while just to check, but flush/bleed all my vehicles every 2 years anywho.

[Jetfixer]

I put the prongs of my little tester in the reservoirs once in a while just to check, but flush/bleed all my vehicles every 2 years anywho.

The reservoir will always show the highest moisture content since it's cap is vented to atmosphere. You have no way of knowing without flushing how much of that moisture has made its way through all the lines and components of the system. I always use a syringe to draw out as much of the reservoir fluid as I can before starting a flush procedure. That way, I'm not starting off pushing all that moisture through everything else.

[Knizar]

The reservoir will always show the highest moisture content since it's cap is vented to atmosphere. You have no way of knowing without flushing how much of that moisture has made its way through all the lines and components of the system. I always use a syringe to draw out as much of the reservoir fluid as I can before starting a flush procedure. That way, I'm not starting off pushing all that moisture through everything else.

Good instructions, I was planning on drawing out most of the fluid in the reservoir before starting the flush.

[bikerchris1270]

The factory recommended interval for brake fluid flushing is every 2 years. Yes, of course you can bleed the brakes the old fashioned way, one wheel at a time. However, there is no way to bleed the ABS unit without hooking up to BUDS/BUDS2. During the procedure, BUDS will tell you which wheel to do and for how long. It will then have you bleed the ABS unit. During this step of the procedure, BUDS will cycle the ABS unit on and off numerous times, getting all of the old fluid out and replaced with new clean fluid. I did a flush on a friends 2016 F3T today. The bleeder screw on the ABS unit has considerable corrosion and the fluid that came out is very cloudy, dirty, and contaminated with water. (Brake fluid absorbs water out of the air). Getting all this moisture out of the fluid will prevent corrosion in your calipers, brake lines, and ABS unit. Corroded calipers and/or ABS unit can prevent them from functioning properly, which means they might not apply properly or release properly causing dragging brakes.

I flushed the brake fluid on my 2019 F3L this afternoon using the BUDS interface……..I was surprised how much crap came out of ABS Pump bleed port……….the positive of bleed is the Brake Pedal is Firmer now.

[UtahPete]

The reservoir will always show the highest moisture content since it's cap is vented to atmosphere. I always use a syringe to draw out as much of the reservoir fluid as I can before starting a flush procedure. That way, I'm not starting off pushing all that moisture through everything else.

Good idea.

[Freddy]

The reservoir will always show the highest moisture content since it's cap is vented to atmosphere. .......

Where's the proof? Guesswork doesn't cut the mustard.

The cap is vented but the fluid is sealed from the atmosphere by the rubber diaphragm under the cap.

[UtahPete]

Where's the proof? Guesswork doesn't cut the mustard.

The cap is vented but the fluid is sealed from the atmosphere by the rubber diaphragm under the cap.

All seals leak, some more than others. Who cuts mustard, anyway?

[Freddy]

All seals leak ....

Not so.

[UtahPete]

Not so.

Good luck proving that.

Anyway, it makes sense to me that moisture would enter the closed system at the seal between the diaphragm and the reservoir body.

[Jetfixer]

Where's the proof? Guesswork doesn't cut the mustard.

The cap is vented but the fluid is sealed from the atmosphere by the rubber diaphragm under the cap.

If you take your caps off and look closely, you'll see chevron shaped vents in the rubber diaphragms. Here's the proof from the service manual. The 2020 and newer RT and F3's with the single reservoir cap have a one piece diaphragm that is not slitted, but the single cap is held on by a wire retainer that does not hold the cap as tightly as the earlier caps. These still manage to get lots of dirt under the edges of the seal which indicates air getting in.

diaphragm.jpg

[Freddy]

Well done Jet - go to the top of the class.

[Jetfixer]

If you have the older two cap system, be sure to place the caps back on with the slit to the rear.

[Little Blue]

...Son, there are several ways to get a job done.
The correct way, the wrong way and something in between.

For Best Results, do it the correct way and take your Time.

Stay Healthy and Be Safe. .....

[Woodenfish]

All seals leak, some more than others. Who cuts mustard, anyway?

After following this thread I became concerned about the possibility of having brake fluid contamination on my low mile 2021 Spyder and prepared myself for performing this service by myself with the installation of Speedbleeders. I was shocked at the deep discoloration of the fluid and how it happened happened so quickly. Looking at the brake fluid reservoir cap and seal I think I see the problem. This looks to be a very poorly thought out seal design along with a reservoir placement that is less than ideal. The engineer who signed off on this should be very concerned about their job. This fluid really needs to be changed at much shorter intervals than specified under current design conditions.

The simple process of carefully hand washing your motorcycle adds a significant risk of water infiltration into your brake fluid reservoir. The reservoir certainly should be at least redesigned and the seal needs to be of better fit. Perhaps a fellow enterprising Spyder owner could make a 3-D printed cover to act as an umbrella for the reservoir or some sort of seal could be added to the body side panel to help keep the water out of the engine area until BRP recognizes this engineering error.