Brake Fluid Compatability

[Vstar2FJR]

My 05 FJR is coming up for the 16K service and I want to change all the brake and clutch fluids. At about 5000 miles I changed the front brake and clutch fluid because it was all dark green/brown as described by Warchild in FJRTech. At that time, I used a good DOT 4 fluid, non synthetic. The rear reservior has stayed clean and clear, so I haven't futzed with it till now.

My intent at 16K was to use the Valvoline Synthetic DOT 4 fluid in all 3 locations, because at Warchild has said, it's the "Dog's Dangles" (or words to that effect). The Valvoline bottle says it is compatible with all brake fluids. The dealer service rep told me it isn't a good idea to switch from a non syn to a syn fluid because it would affect the seals and overall brake performance. They have allegedly had bikes come in with problems with the brake system when folks did that.

I'm thinkning this is a load of crap, but want to hear the collective wisdom of this forum, even the sarcastic, smart a$$ed comments from RAD (just messin' with ya buddy )

BTW, I've moved off the EZ Board forum, hope I'm allowed to mention that here!

 

[radman]

Silicone (dot5) and dot 4 won't mix, but dot 4 is dot 4. Seals etc would not be a concern, only the fact that the benefits gained by using a syn would be lessened in the mix. Best would be to flush the systems with the syn fluid (recommended periodically anyway) to gain all the bennys of the syn.

 

[Vstar2FJR]

Thank you Rad. If it's the same Valvloline bottle that's pictured in the FJRTech article about changing the clutch fluid, I should be OK as it says it's DOT 3/4.

I was planning on doing the complete bleed using the Valvoline as you mentioned, so I guess I ws given a load of bull.

John

 

[radman]

Bull yes, but understandable. Brakes are a sensitive subject to a shop, as even the slightest misunderstanding concerning reccomendations usually leads to a lawsuit if the shit hits the fan, regardless of the cause, as an attorney gravitates toward deep pockets. That he answered at all is a point in his favor. In any case, he was probably thinking slicone fluid.

 

[f1fan]

What about DOT5.1 brake fluid? I heard that it is Glycol based and can be used in the FJR mixing with DOT4. Anybody tried this yet?

Also, how much fluid does the FJR ABS need to do a flush on all the brakes and the clutch?

 

[teerex51]

F1fan,

My € .20

I wouldn't mix DOT 5.1 with DOT 4.

I do not know the actual capacity of the brake and clutch reservoirs (and I don't think it really matters). You need to get the air out and you'll end up wasting quite a bit of fluid in the process.

I would suggest you have at least a pint handy. Nothing worse than having to stop flushing your brake system because you ran out of fluid. :angry: :headbonk:

Stef

 

[C&C]

What about DOT5.1 brake fluid? I heard that it is Glycol based and can be used in the FJR mixing with DOT4. Anybody tried this yet?
Also, how much fluid does the FJR ABS need to do a flush on all the brakes and the clutch?

Not much point in mixing brake fluids, they're fairly cheap and doesn't take much for flushing all resevoirs. I bought a pint of Prestone Dot 4, did all the flushes, finished the bleeding, topped off the resevoirs and still had some left over.

 

[afterburn]

5.1 and 4 mix fine. They both are Glycol based and are the same, except for the hot/wet boilingpoints.

 

[f1fan]

teerex,

sorry when I said mixing, I actually meant flushing the old DOT4 and filling in the new DOT5.1

I plan on cleaning out the whole system.

However, as afterburn stated already mixing the two is OK as well and that's the info I get when I looked

up different DOT5.1 brands on the web. They all say that mixing the two is no problem.

I think I will get a 0.5 or 1 liter bottle and give it a try. The 5.1 stuff is supposed to last longer as well. Plus they say it's good for

using in ABS systems. I plan on using it in the clutch as well.

Thanks for all the answers and suggestions

 

[FJRottie]

DOT3 and DOT4 are glycol-based fluids, which absorb water. DOT5 is a silicone-based fluid and does not absorb water.

Thanks to Dave Zeckhausen : Lets look at what the DOT ratings mean.  The table below shows the MINIMUM wet and dry boiling points for DOT 2, 3, 4, and 5 brake fluid in degrees fahrenheit.

                          DOT 2  DOT 3  DOT 4  DOT 5

Dry Boiling point    374      401      446      500

Wet boiling point              284      311      356

The DOT 2 spec is for drum brakes and is obsolete.  If you have any DOT 2 in your garage, throw it away!  DOT 5 is for silicone brake fluid.  Silicone brake fluid (DOT 5) should be avoided because  it is not compatible with regular brake fluid, it is hard to pour  without introducing bubbles and thus results in soft pedal feel, and moisture still gets into your system and will pool in low areas like your calipers and encourage rapid corrosion.  STAY AWAY!

That leaves DOT 3 and DOT 4 fluids.  These fluids are compatible with each other and may be interchanged or mixed with no ill effects.

Let's look at some popular brake fluids and their boiling points:

  Fluid                            DRY  WET

Castrol LMA DOT  3/4      446    311

Ford Heavy Duty DOT 3  550    290

ATE Super Blue Racing    536    392

ATE TYP 200                  536    392

Motul Racing 600            585    421

Castrol SRF                    590    518

Performance Friction        550    284

 

[f1fan]

DOT3 and DOT4 are glycol-based fluids, which absorb water. DOT5 is a silicone-based fluid and does not absorb water.

DOT 5.1 is also glycol based and can be mixed with DOT 3 & DOT 4 fluid.

Here is some info: Clicky

I like the sounds of the long life 5.1 version. 10 Years!!!!!

Don't mind the annoying music!

 

[afterburn]

Yes, it is confusing that there is silicon based DOT5 and glycol based DOT5.1. The name was introduced, because DOT5.1 has similar characteristics as DOT5 yet it doesn't have the downsides of it since it is glycol based instead of silicon.

 

[Vstar2FJR]

Now you can see why I started this discussion in the first place. I guess it turns out that what the dealer told me was essentially correct, don't mix DOT 3/4 with DOT 5. DOT 5.1 may indeed be a different animal than DOT 5, but I don't need to worry about any of this. Had the Valvoline synthetic put in last weekend, brakes feel great at 16500 miles.

John

 

[Rogue]

teerex,
sorry when I said mixing, I actually meant flushing the old DOT4 and filling in the new DOT5.1

I plan on cleaning out the whole system.

However, as afterburn stated already mixing the two is OK as well and that's the info I get when I looked

up different DOT5.1 brands on the web. They all say that mixing the two is no problem.

I think I will get a 0.5 or 1 liter bottle and give it a try. The 5.1 stuff is supposed to last longer as well. Plus they say it's good for

using in ABS systems. I plan on using it in the clutch as well.

Thanks for all the answers and suggestions

I would never buy a lot larger bottle than I'm going to use. Due to the hygroscopic properties once you break the seal it will start absorbing moisture.

 

[f1fan]

I would never buy a lot larger bottle than I'm going to use. Due to the hygroscopic properties once you break the seal it will start absorbing moisture.

I hear you. A liter may be too much. Then my question is, how much approximately do I need to flush all the brakes and the clutch? Is a 0.5 liter bottle sufficient? ABS bike here, I guess I need a bit more fluid.

 

[donaldb]

Silicone (dot5) and dot 4 won't mix, but dot 4 is dot 4. Seals etc would not be a concern, only the fact that the benefits gained by using a syn would be lessened in the mix. Best would be to flush the systems with the syn fluid (recommended periodically anyway) to gain all the bennys of the syn.

So soon I'm performing a break and clutch fluid flush. I have a set of speed bleeders, been sitting on the shelf for a year and decided to do it all at 1 time especially w/NAFO trip coming up.

So.............

From what I'm reading above, it is ok to switch to the dot 4 syn when I flush the system both clutch and breaks. But what about the ABS reservoir? My understanding w/ABS system there is no way to remove all the fluid in a flush, some will remain..........will the mix of the 2 be ok so long as they are both 4s??

 

[C&C]

DOT 3 and 4 are compatible; the only difference is that DOT 4 is synthetic. The reason 3 & 4 don't mix with 5 is because 5 silcone based and 3 & 4 are mineral based.

https://books.google.com/books?id=g3v3MXzJE...hl=en#PPA534,M1

 

[JamesK]

Can someone who's done a brake & cluch fluid flush pls tell me how much fluid they required?