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Basic Maintenance: Brake Fluid
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rdprdp01 Offline
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RE: Basic Maintenance: Brake Fluid
#11

(01-19-2026, 04:50 AM)Tev62 Wrote: Very comprehensive rdprdp01. I would add the brake fluid testers are extremely cheap now and it is a simple task to test the amount of water content in the brake fluid resovoir. Up to 4% is considered the limit but you might make a choice to replace earlier. It is hard for the brake fluid to ingest water as the resovoir does has a flexible rubber cap, the pinhole is above that to allow for expansion and contraction of that cap without fully exposing the resovoir fluid to any more air than it currently is. Not impossible of course, I have a classic car sitting here with 5% plus contamination and it is only 3 years since its fluid replacement.

While you were there you might of done the clutch fluid, it's an easy change too.

Thanks for the suggestion. To be candid, I was not even aware that a brake fluid tester existed! I have noticed that there are are several price points for various testers. Please advise if you think this unit would make a reasonable addition to my tool collection:

QRPKIng AS501

As for the clutch fluid, sadly work is getting in the way of my quality time with my CB1100EX. The clutch fluid change is on the list of things to do after I take care of a few more maintenance items. Thanks again for the suggestion. I really enjoy your Threads and Posts. David

2017 Honda CB1100 EX
The most sophisticated, smooth, perfectly engineered motorcycle I've ever owned. A pleasure in every way.


01-19-2026, 08:34 AM
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Tev62 Offline
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RE: Basic Maintenance: Brake Fluid
#12

(01-19-2026, 08:34 AM)rdprdp01 Wrote:
(01-19-2026, 04:50 AM)Tev62 Wrote: Very comprehensive rdprdp01. I would add the brake fluid testers are extremely cheap now and it is a simple task to test the amount of water content in the brake fluid resovoir. Up to 4% is considered the limit but you might make a choice to replace earlier. It is hard for the brake fluid to ingest water as the resovoir does has a flexible rubber cap, the pinhole is above that to allow for expansion and contraction of that cap without fully exposing the resovoir fluid to any more air than it currently is. Not impossible of course, I have a classic car sitting here with 5% plus contamination and it is only 3 years since its fluid replacement.

While you were there you might of done the clutch fluid, it's an easy change too.

Thanks for the suggestion. To be candid, I was not even aware that a brake fluid tester existed! I have noticed that there are are several price points for various testers. Please advise if you think this unit would make a reasonable addition to my tool collection:

QRPKIng AS501

As for the clutch fluid, sadly work is getting in the way of my quality time with my CB1100EX. The clutch fluid change is on the list of things to do after I take care of a few more maintenance items. Thanks again for the suggestion. I really enjoy your Threads and Posts. David

Yes, that looks OK. There are so many on the market. I got two from Ali-Express, less than $5 each I think. I got two just to check they read the same. And as you are stuck for time it would take you 2-3 minutes to check the fluid in the resovoir.


01-20-2026, 08:18 AM
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rdprdp01 Offline
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RE: Basic Maintenance: Brake Fluid
#13

True that, Tev62. I knew it would take some time to touch up the photos and create the "How To," so I did both after I changed the brake fluid. Sadly, the clutch fluid is still aging like fine wine. Smile

My time management and work/life balance needs some work, too. David

2017 Honda CB1100 EX
The most sophisticated, smooth, perfectly engineered motorcycle I've ever owned. A pleasure in every way.


01-23-2026, 11:08 PM
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rdprdp01 Offline
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RE: Basic Maintenance: Brake Fluid
#14

(01-18-2026, 01:53 PM)peterbaron Wrote: My biggest reservations are the length of this procedure and the fact that brake fluid is pumped in the opposite direction of normal flow, meaning that any sludge that has accumulated in the calipers must be flown through the ABS, brake master, compensation port, and back to the reservoir, as well as air bubbles in the brake system when this procedure is completed.

I ultimately came to the same conclusion, which is why I followed the traditional method. And I feel particularly proud of my decision after reading your post. You remain my mechanic role model! David

2017 Honda CB1100 EX
The most sophisticated, smooth, perfectly engineered motorcycle I've ever owned. A pleasure in every way.


01-23-2026, 11:14 PM
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