Dot4 vs V10

[BER18 100]

I always used dot4 hydraulic fluid on my R1200C for both brake lines and clutch lines.
With the R18, BMW uses V10 for clutch. OReilly didn’t know what I was talking about when I asked for V10!

Was told today on the phone that this fluid is lifetime, i.e. won't need to change for the life of the bike.

 

[1911tex]

I always used dot4 hydraulic fluid on my R1200C for both brake lines and clutch lines.
With the R18, BMW uses V10 for clutch. OReilly didn’t know what I was talking about when I asked for V10!

Was told today on the phone that this fluid is lifetime, i.e. won't need to change for the life of the bike.

Love good news! And that is good news!

 

[BobW]

The clutch uses mineral oil concoction and should not be mixed with dot4, etc. Brake fluid will damage seals and if used in an emergency should be flushed asap! Magura offers a mineral oil if you can't locate the V10.

I haven't looked on my. R18, but in the past BMW has the type of fluid to use imprinted on the cap.

click

 

[Hammo]

I can inform you from painful experience , do not use Dot4 as clutch fluid on R1800 , it will perish the clutch rubber in the resovoir will lead to other problems , clutch fluid is mineral on an R1800 i know and it was a costly experience .

 

[RazMan]

Wow! Now that is something I have learned today

 

[BER18 100]

GOOD to know this. I need to get educated. Sounds to me like V10 is similar to dot5 mineral oil.

 

[Cu Dubh]

The head mechanic at my dealership told me about the mineral oil-based clutch fluid. I had asked them to change the fluid because it had darkened and, based on years of using standard DOT hydraulic clutch & brake fluid, which is hygroscopic, and a couple of clutch slave cylinder failures on my GS, I wanted the fluid changed. Which they did.
Mineral oil is not hygroscopic, it's apparently hygrophobic; perhaps it was unnecessary but I felt better with fresh, clean clutch fluid.
Interesting article here, though it is bicycle-centric.
https://www.bikeradar.com/advice/buyers-guides/brake-fluid-mineral-oil-vs-dot

 

[tngarren]

I accidently added DOT 4 to the R18 clutch reservoir. Stupid me. Remained there for maybe a week and 100 miles before I realized my mistake. I removed all the fluid from master cylinder, cleaned it, and refilled with Spectro 10 mineral oil. Did not flush entire system. DOT 4 is heavier than 10W mineral oil so it probably got to the slave cylinder. I'll watch for leaks and poor clutch operation and go on from there.

Funny thing, I asked ChatGPT about R18 clutch fluid type before topping off and reply was DOT 4. So much for AI lol. There is no mention on the R18 reservoir lid. Thanks BMW.

 

[Hammo]

I was shown the in side of the clutch reservoir and sure enough the rubber insert had perished with the DOT-4 .

 

[tngarren]

Interesting how other bikes with DOT 4 brakes and clutches with rubber inserts don't perish. BMW must have picked a specific rubber to punish us for our mistakes.

 

[BER18 100]

Until the R18, I always used Dot4 in both. Silly to not use the same.

 

[Keehn]

From what I understand, the blue V10 "mineral oil" is used in the clutch assembly because it's meant as a "lifetime fluid", and it doesn't absorb water. However, it doesn't have the anti-boiling properties of standard DoT 3-4 fluids. But, because it's used in a low-temp application (pressing clutch lever), it's perfectly acceptable.

Understand that BMW used to use "lifetime fluid" in their vehicle transmissions, which I liked to joke "yeah, the fluid lasts....right up to transmission failure". So, I'd take the blue V10 "lifetime" claim with the same grain of salt I gave bimmer transmissions.

Just flush out the blue V10 and replace with fresh V10, and you'll be fine.

Mike

 

[MilwDave]

The BMW clutch fluid is inexpensive (around $8 if I remember correctly) so why look for an alternative?

 

[BER18 100]

I get the lifetime use idea for the clutch now that you clarified it.