ABS Brake Recall
#161
03-29-2018, 06:47 AM
#162
03-30-2018, 11:08 AM
Seasoned HDF Member
The military wanted a brake fluid that was more environmentally stable, among other standards. A fluid that would not absorb water in a humid environment, a fluid that would not freeze in cold environments, a fluid that could be left in vehicles for long term storage. Silicone satisfied that requirement. Current milspec is MIL-PRF-46176B.
You can download a copy of the current milspec here:
http://everyspec.com/MIL-PRF/MIL-PRF...F-46176B_6492/
It is worth note that the milspec is different than the NHTSA DOT5 spec. The various NHTSA DOT brake fluid specifications can be downloaded here:
https://www.gpo.gov/fdsys/pkg/CFR-20...sec571-116.pdf
Silicone fluids have no special attractive properties related to oxygen. However silicone fluids can suspend or otherwise retain more air suspended in the fluid than glycol. Excerpted from SAE J1705, Appendix A, A.2.2.8,
"It has been reported that dimethyl polysiloxane fluid, which is a major part of silicone-based, low water-tolerant type brake fluids can typically contain dissolved air at a level of 16% ±3% by volume at standard temperature and pressure. This compares with a typical level of 5% ±2% by volume of dissolved air for glycol ether based type fluids."
This suspension of air can create a more spongy brake pedal feel than glycol fluids. Coming from that same SAE J1705 standard; "An increase in brake pedal travel may be experienced under severe operating conditions, especially at higher altitudes and high temperature conditions."
I know of no free download of SAE J1705. However one can download it here:
https://www.sae.org/standards/content/j1705_199505/
This air retention and foaming or sponginess has been used as the basis of the claim that silicone brake fluids are unsuitable for use in ABS systems. The claim being that the rapid cycling of the hydraulic components in the ABS module would froth the fluid. Where the air would come from is left unexplained.
However, the Army commissioned a study on this. The results of this study showed silicone fluid to be incompatible with ABS systems. Not for frothing reasons, but for wear problems owing to the lower lubricity of silicone fluids.
This military report can be downloaded here:
https://events.esd.org/wp-content/up...quirements.pdf
And as a semi-sidebar, the military also investigated claims of silicone brake fluid suddenly becoming highly compressible in non-abs vehicles, resulting in catastrophic brake failure. The results of the study contra-indicated these claims, showing the cause to be conventional brake fade.
This military report can be downloaded here:
http://www.dtic.mil/dtic/tr/fulltext/u2/a251835.pdf
You can download a copy of the current milspec here:
http://everyspec.com/MIL-PRF/MIL-PRF...F-46176B_6492/
It is worth note that the milspec is different than the NHTSA DOT5 spec. The various NHTSA DOT brake fluid specifications can be downloaded here:
https://www.gpo.gov/fdsys/pkg/CFR-20...sec571-116.pdf
Silicone fluids have no special attractive properties related to oxygen. However silicone fluids can suspend or otherwise retain more air suspended in the fluid than glycol. Excerpted from SAE J1705, Appendix A, A.2.2.8,
"It has been reported that dimethyl polysiloxane fluid, which is a major part of silicone-based, low water-tolerant type brake fluids can typically contain dissolved air at a level of 16% ±3% by volume at standard temperature and pressure. This compares with a typical level of 5% ±2% by volume of dissolved air for glycol ether based type fluids."
This suspension of air can create a more spongy brake pedal feel than glycol fluids. Coming from that same SAE J1705 standard; "An increase in brake pedal travel may be experienced under severe operating conditions, especially at higher altitudes and high temperature conditions."
I know of no free download of SAE J1705. However one can download it here:
https://www.sae.org/standards/content/j1705_199505/
This air retention and foaming or sponginess has been used as the basis of the claim that silicone brake fluids are unsuitable for use in ABS systems. The claim being that the rapid cycling of the hydraulic components in the ABS module would froth the fluid. Where the air would come from is left unexplained.
However, the Army commissioned a study on this. The results of this study showed silicone fluid to be incompatible with ABS systems. Not for frothing reasons, but for wear problems owing to the lower lubricity of silicone fluids.
This military report can be downloaded here:
https://events.esd.org/wp-content/up...quirements.pdf
And as a semi-sidebar, the military also investigated claims of silicone brake fluid suddenly becoming highly compressible in non-abs vehicles, resulting in catastrophic brake failure. The results of the study contra-indicated these claims, showing the cause to be conventional brake fade.
This military report can be downloaded here:
http://www.dtic.mil/dtic/tr/fulltext/u2/a251835.pdf
Ok.... I admit it, you do a much better job of being Cliff than I do.....
I'd rather be Norm anyways.....
#163
04-02-2018, 05:50 PM
Ultimate HDF Member
Okay.... Serious follow up question.
After reading, digesting, absorbing and toiling over my ABS brakes, I have a question.
I am seriously concerned about this brake failure issue. Even though my '13 seems to not be part of the recall. It sounds to me like the issue is the ABS units freeze up, and thats where the trouble ensues. To me, it sounds like the issue is the ABS goes for years without being activated, or having the fluid changed, then fails at the worst time. Luckily, or unluckily as the case may be, I live on a dirt road. Yesterday as the case may be, I jacked both my front and rear brakes, and fully activated both my front and rear ABS units three separate times. Should I do this "activation of my ABS system" on a fairly regular basis? By doing this, can I effectively eliminate the issue of the ABS failing? I guess what I don't know is....
Is the problem that the system goes unused for many years, goes unflushed, then fails at the wrong time???
I just don't know and wanted to shoot this around...
And is regularly force activating it a possible solution??
Please advise.
After reading, digesting, absorbing and toiling over my ABS brakes, I have a question.
I am seriously concerned about this brake failure issue. Even though my '13 seems to not be part of the recall. It sounds to me like the issue is the ABS units freeze up, and thats where the trouble ensues. To me, it sounds like the issue is the ABS goes for years without being activated, or having the fluid changed, then fails at the worst time. Luckily, or unluckily as the case may be, I live on a dirt road. Yesterday as the case may be, I jacked both my front and rear brakes, and fully activated both my front and rear ABS units three separate times. Should I do this "activation of my ABS system" on a fairly regular basis? By doing this, can I effectively eliminate the issue of the ABS failing? I guess what I don't know is....
Is the problem that the system goes unused for many years, goes unflushed, then fails at the wrong time???
I just don't know and wanted to shoot this around...
And is regularly force activating it a possible solution??
Please advise.
Last edited by bikerlaw; 04-02-2018 at 05:51 PM.
#164
04-02-2018, 05:57 PM
#165
04-02-2018, 06:13 PM
Ultimate HDF Member
Agreed! I can't think of a better way of explaining it.
But.... Is it a solution? Does bleeding my brakes, doing a handfull of ABS dirt road activations, and reflushing the system, fully flush and clean my system? I don't want to bet my life on it, but bypassing the ABS unit completely seems to be the only "other" option.
But.... Is it a solution? Does bleeding my brakes, doing a handfull of ABS dirt road activations, and reflushing the system, fully flush and clean my system? I don't want to bet my life on it, but bypassing the ABS unit completely seems to be the only "other" option.
#166
04-02-2018, 06:48 PM
It's no match for the full and proper flush. It's better than not doing anything. The more you do it, the more you mix and change the fluid. You'll also learn the traction limits of your brakes and become comfortable with your abs.
All in all, a win-win in my book. But, it's just not as effective at fully flushing all the fluid as a full proper flush job is.
All in all, a win-win in my book. But, it's just not as effective at fully flushing all the fluid as a full proper flush job is.
#167
04-02-2018, 06:57 PM
#168
04-02-2018, 08:04 PM
Sorry about your ABS failure. I hope no one was hurt except for your wallet and welcome to the growing group of disgruntled Harley owners with failed ABS systems. Please report to the NHTSA. Maybe if enough of us report they will change this bogus recall to include more than a free fluid flush.
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