Brake fluid capacity - change without flush
#11
08-27-2023, 12:14 PM
The testers conductivity/boiling point/strips are measuring only in the brake fluid in the reservoir not what's in the lines or your calipers.
Both can give some piece of mind but in reality, you cannot know for certain your "complete" brake fluid condition without a measurement from the reservoir and each caliper bleeder.
I'll use drinking water as an example: You can have well or public water that test fine but when tested at one of your taps can have lead or other containments.
And if you are going to test each caliper you might as well change the fluid out.
Both can give some piece of mind but in reality, you cannot know for certain your "complete" brake fluid condition without a measurement from the reservoir and each caliper bleeder.
I'll use drinking water as an example: You can have well or public water that test fine but when tested at one of your taps can have lead or other containments.
And if you are going to test each caliper you might as well change the fluid out.
Here is why for normal fluid evaluation quick check it is done primarily and the most often at the resivoir. .
The reason most service technicians does not check each caliper is the human reason PIA and the technical reason the revisor is the first line which would be the most likely to get an idea of the overall brake fluid condition. Generally speaking, if the caliper was tested and shown to be of higher values comparing the revisor then you would also have seepage or brake fluid leak if even a small residue. When a truly experienced or actual trained "mechanic" or Automotive technician test the brake fluid they hopefully are looking at the overall condition of the brakes and if there are any tail tale signs of brake fluid leaks or residue from worn brake parts.
You know it funny but "testing" brake fluid in not on any ASE test questions nor do I ever recall it ever being on any general brake questions with any trade schools or automotive technical institutions? I just looked through mine.
I also looked at an old application for teaching I once was considering to do part time at a Aeromechanical institution and the brake scheduling coarse.... nothing there under fluid testing?? LOL
Also my Aircraft certification NEVER mentioned testing the brake or brake hydraulic fluids only when to service them?
I guess it has been one of those things I simply have done and relied on the results for about 4 decades?
Last edited by Callisto; 08-27-2023 at 12:25 PM.
#12
08-28-2023, 07:56 AM
If you do the research on independent testing sites, you see the test strips you use and the units that measure boiling point are pretty good.
However, the pen style conductivity units aren't very good at all. They aren't very accurate, if at all, and most people as you mentioned don't clean them properly.
They are basically for a false piece of mind much like some of the tire pressure alert systems in vehicles.
Plus, they are also only good for about two years then the probes fail. I can tell you in the lab we changed our conductivity meter probes on a regular basis and when they weren't in use they were kept in a neutral solution.
I "normally" change (now the shop does) my brake fluid when my brake pads are changed which is about every 2-3 years for me now.
Having ridden motorcycles off/on road and on the track for years I've always been very brake conscious which meant changing fluid yearly on them.
However, the pen style conductivity units aren't very good at all. They aren't very accurate, if at all, and most people as you mentioned don't clean them properly.
They are basically for a false piece of mind much like some of the tire pressure alert systems in vehicles.
Plus, they are also only good for about two years then the probes fail. I can tell you in the lab we changed our conductivity meter probes on a regular basis and when they weren't in use they were kept in a neutral solution.
I "normally" change (now the shop does) my brake fluid when my brake pads are changed which is about every 2-3 years for me now.
Having ridden motorcycles off/on road and on the track for years I've always been very brake conscious which meant changing fluid yearly on them.
#13
08-28-2023, 09:47 AM
If you do the research on independent testing sites, you see the test strips you use and the units that measure boiling point are pretty good.
However, the pen style conductivity units aren't very good at all. They aren't very accurate, if at all, and most people as you mentioned don't clean them properly.
They are basically for a false piece of mind much like some of the tire pressure alert systems in vehicles.
Plus, they are also only good for about two years then the probes fail. I can tell you in the lab we changed our conductivity meter probes on a regular basis and when they weren't in use they were kept in a neutral solution.
I "normally" change (now the shop does) my brake fluid when my brake pads are changed which is about every 2-3 years for me now.
Having ridden motorcycles off/on road and on the track for years I've always been very brake conscious which meant changing fluid yearly on them.
However, the pen style conductivity units aren't very good at all. They aren't very accurate, if at all, and most people as you mentioned don't clean them properly.
They are basically for a false piece of mind much like some of the tire pressure alert systems in vehicles.
Plus, they are also only good for about two years then the probes fail. I can tell you in the lab we changed our conductivity meter probes on a regular basis and when they weren't in use they were kept in a neutral solution.
I "normally" change (now the shop does) my brake fluid when my brake pads are changed which is about every 2-3 years for me now.
Having ridden motorcycles off/on road and on the track for years I've always been very brake conscious which meant changing fluid yearly on them.
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