Wetheads dot 4 brake fluid thread

[taylor1]

Didn't want to hijack their thread nor turn this into an oil thread. After reading a bit about the 5.1 fluid, I am wondering if it would be safe to use it on my 1150rt. I would think anything that is less hydroscopic would be benefit to the old ABS. Any suggestions are welcome as it is time for a flush this winter. TIA

[George S.]

The way I understand it is DOT 5.1 is compatible with DOT 4 since they are both glycol based.
DOT 5 is very different and should not be mixed or interchanged with any other. 

[Mike279]

I have been using the Bosch 5.1 in my 04 for a few years and it is working fine.  I really can't find find a single reason to not use it. 

[dirtrider]

6 hours ago, taylor1 said:

Didn't want to hijack their thread nor turn this into an oil thread. After reading a bit about the 5.1 fluid, I am wondering if it would be safe to use it on my 1150rt. I would think anything that is less hydroscopic would be benefit to the old ABS. Any suggestions are welcome as it is time for a flush this winter. TIA

Morning taylor1

 

There is compatible, then there is recommended.

 

Just remember that your 1150 is a servo pump assist ABS equipped motorcycle. All the ABS calibrations & ABS orifice sizes are based on the DOT 4 fluid characteristics. 

 

The DOT 5.1 is close but not exactly the same or it would be called DOT 4 - DOT 5.1. 

 

 

 

 

[JamesW]

If you want to improve the brake system on your 1150 it's simple.....just remove the ABS system altogether, just my humble opinion.  Been there done that!  Then if you want to really improve things sell the 1150 and maybe find yourself a good condition low miles 1100 then just pull the CCP and go down the road happily ever after.

[Skywagon]

I guess I don't get it.  There have been so many reports of failed ABS units which require a very large sum of money to fix/replace or a pretty hard project to remove the pump taking away the safety of ABS. It just doesn't make sense to me to risk the ABS unit for a fluid out of engineered spec.  When I had my 1150RT it was flushed IAW the mfg instructions to flush the ABS unit and the brakes.  It never failed me or gave me a minutes trouble.  I have done the same on my 2014 since new.  To me it's a simple formula........fluids cheap....repairs expensive and time consuming.

[taylor1]

Thanks D.R.and Skywagon   common sense answers.

[Hosstage]

A certain other brand of motorcycle found out the hard way that flushing the abs every two years with the abs pump being activated during service is a requirement, not a suggestion. The fail safe on that system is not safe at all, but freezes the handle and foot pedal from working, allowing no brake activation at all. Nice system. Can't believe it has not been recalled yet in almost 15 years.

Mine gets properly flushed every two years with dot4.

[Skywagon]

osstage....wow...no brakes no bueno.  Back when my 1150 was new I was headed towards the garage at maybe 15mph.  About 150 ft out I killed the engine.  Boy was I surprised when I had virtually no brakes.  I did pull and stomp hard enough to not go through the back wall, but learned a valuable lesson.  I can't image 

12 minutes ago, Hosstage said:

certain other brand of motorcycle that might weigh close to 900 lbs suddenly with no brakes.

[Hosstage]

18 minutes ago, Skywagon said:

osstage....wow...no brakes no bueno.  Back when my 1150 was new I was headed towards the garage at maybe 15mph.  About 150 ft out I killed the engine.  Boy was I surprised when I had virtually no brakes.  I did pull and stomp hard enough to not go through the back wall, but learned a valuable lesson.  I can't image 

Yes, evidently if the abs is not activated on a normal basis (most don't use their brakes hard enough to do it, especially the front brake, no linked system) the fluid crystalizes in the abs pump and will not allow the brakes to work at all. There is no bypass system like every automobile and other bike brand has. It has caused some real problems, and requires a new abs system to be installed, not a serviceable item. And still no recall.

 

Sorry everybody, I didn't mean to hijack this thread on a tangent. I just meant to point out the importance of regular maintenance on the abs system.

[dirtrider]

2 hours ago, Hosstage said:

Yes, evidently if the abs is not activated on a normal basis (most don't use their brakes hard enough to do it, especially the front brake, no linked system) the fluid crystalizes in the abs pump and will not allow the brakes to work at all. There is no bypass system like every automobile and other bike brand has. It has caused some real problems, and requires a new abs system to be installed, not a serviceable item. And still no recall.

 

Sorry everybody, I didn't mean to hijack this thread on a tangent. I just meant to point out the importance of regular maintenance on the abs system.

Evening  Hosstage

 

On the wethead__

 

Actually on the linked systems the ABS (servo) pump is run every time the front brake lever is used. That is how the rear brake is linked to the front brake apply. This only happens with the key-on as the ABS needs to be on & booted for the rear brake linking to work. 

 

With the linked system just put the motorcycle on the center stand,  then turn the key on, then while spinning the rear wheel with your foot pull the front brake lever. The servo pump will come on & the rear brake will lock up. No do this with the key off & you have nor rear brake linking.  

 

 

The ABS (anti-lock) part is just a release of the braking pressures & those valves are cycled at every initial ride off with the engine running as part of the ride-away system check.   

 

On the 1150 there are 2 servo pumps & those run every time the front brake is used on a linked I-ABS system. The ABS valves are cycled at every fresh engine start rideaway as part of the system self test.  

[Mattlo]

One thing to keep in mind…

The higher boiling points of these DOT fluids also means the fluids are more hygroscopic. Which means they should be flushed more often due to moisture absorption. 
 

also note 5.1 is not the same base as 5, which is the silicone base.  As others noted 5.1 is same base as 3 and 4.  And is hygroscopic. 

Edited October 5, 2022 by Mattlo

[Mike279]

I know you can't believe everything you read but the sales pitch is pretty good. 

Designed to improve your life

 

• Bosch ESI6 is the next generation brake fluid. It exceeds all current DOT standard requirements (FMVSS 116)
• First to simultaneously combine both low viscosity and high wet boiling point at its operation
• ESI coverage includes the majority of all brake systems launched since 1990; Use with DOT 3, DOT 4, or DOT 5.1; Coverage excludes DOT 5 silicone based brake fluid which is limited to military and racing applications
• Excellent lubricity properties to prevent wear of components in the brake system and reduce noise
• Longer lasting: 100% longer than DOT 3, 50% longer than DOT 4, and 10% longer than DOT 5.1 (with 30% lower viscosity)
• Wet boiling point ~ 360 DegreeF/Viscosity at -40 DegreeC ~ 685mm2/s

  BOSCH BRAKE FLUID: WHY CHOOSE OUR PRODUCT

  Right from the development stage, modern brake fluids such as Bosch ESI6 are designed to cope with the demands of current and future ESP systems

   

• High wet boiling point [°F ]: The higher the wet boiling point, the lower the risk of formation of vapor bubbles – the main cause of brake failure.
• Viscosity [mm²/s] : The lower the viscosity, the faster response times of ESP. The higher the wet boiling point, the lower the risk of formation of vapor bubbles – the main cause of brake failure.

•  

  High lubricity, less corrosion and wear – the advantages of ESI6:

  • One size fits all: As Bosch ESI6 can be used to substitute almost any brake system launched since 1990
  • Bosch ESI6 reduces corrosion
  • Bosch ESI6 helps reduce the stock of brake fluids thus saving storage space
  • Featuring replacement intervals of 3 years
•