A good alternative to brake fluid for hydro. clutch.

[Karbon]

Any ideas?

I know Magura uses some sort of mineral oil on their stand-alone/universal hydro clutch units.

I was wondering if there is a better alternative to plain old brake fluid.

 

[auntiebling]

why?

 

[OldFatGuy]

Any ideas?

I know Magura uses some sort of mineral oil on their stand-alone/universal hydro clutch units.

I was wondering if there is a better alternative to plain old brake fluid.

You can't use mineral oil in a system designed for brake fluid or vice versa. Just use what the manufacturer recommends.

 

[Seph]

You can't use mineral oil in a system designed for brake fluid or vice versa. Just use what the manufacturer recommends.

+1. the wrong fluid will destroy the seals on the slave and master cylinders.

 

[Crjunkee]

check with a harley shops they use some crazy stuff in there bikes

 

[Jakemate]

If its brake fluid, try the Dot Blue.

 

[stan23]

I've been using ATE superblue on all my bikes and I love the stuff.

 

[mototireguy]

Mineral oil you say?

 

[ST Guy]

The short answer is no. There is nothing better than brake fluid. Brake fluid is a specialized hydraulic fluid that resists compression and can handle a fair amount of heat. Besides the fact that bike and car manufacturers have designed their clutch systems to work with brake fluid, it's just the best choice.

I'd go with a quality 5.1 fluid. Motul makes some good ones. ATE also. And the ATE stuff is available in the standard color and the blue color. That way you can be sure all the old fluid is flushed out when doing fluid changes. You simply alternate colors each time you change out the fluid.

Do NOT use 5.0 which is silicone based. Bad idea. Use either a good DOT 3/4 or 5.1.

 

[stan23]

The short answer is no. There is nothing better than brake fluid. Brake fluid is a specialized hydraulic fluid that resists compression and can handle a fair amount of heat. Besides the fact that bike and car manufacturers have designed their clutch systems to work with brake fluid, it's just the best choice.

I'd go with a quality 5.1 fluid. Motul makes some good ones. ATE also. And the ATE stuff is available in the standard color and the blue color. That way you can be sure all the old fluid is flushed out when doing fluid changes. You simply alternate colors each time you change out the fluid.

Do NOT use 5.0 which is silicone based. Bad idea. Use either a good DOT 3/4 or 5.1.

ATE also has a combo pack of light/dark blue hues so you can alternate.

 

[Jakemate]

I've been using ATE superblue on all my bikes and I love the stuff.

Yeah, that stuff.

 

[Dan Kyle]

The short answer is no. There is nothing better than brake fluid. Brake fluid is a specialized hydraulic fluid that resists compression and can handle a fair amount of heat. Besides the fact that bike and car manufacturers have designed their clutch systems to work with brake fluid, it's just the best choice.

I'd go with a quality 5.1 fluid. Motul makes some good ones. ATE also. And the ATE stuff is available in the standard color and the blue color. That way you can be sure all the old fluid is flushed out when doing fluid changes. You simply alternate colors each time you change out the fluid.

Do NOT use 5.0 which is silicone based. Bad idea. Use either a good DOT 3/4 or 5.1.

Why would you use a DOT 5.1 over DOT 3/4?

Agree with you on the DOT 5.0, this is for systems that are designed to use DOT 5.0 only.

 

[ST Guy]

Why would you use a DOT 5.1 over DOT 3/4?

Agree with you on the DOT 5.0, this is for systems that are designed to use DOT 5.0 only.

DOT 3/4 and DOT 5.1 are the same chemistry. Just as DOT 4 was an improvement over DOT 3 (often sold as DOT 3/4 because it meets both specs - just a marketing call), DOT 5.1 is an improvement over DOT 4. Most of the time, these improvements are higher dry and wet boiling points. And because the chemistry is pretty much the same, all the various DOT 3,4, and 5.1's absorb moisture at pretty much the same rate, though some absorb moisture a bit faster than others.

DOT 5 (5.0) should have been named something else from the very beginning. Or at the very least, DOT 5.1 should have been DOT 6. At the time DOT 5 fluid was being developed, there was no other improved standards in the pipeline for the DOT 4 type fluids. So, the folks who set the standards, in their great wisdom, picked the number 5 to designate the next "improvement" in brake fluids. Little did they know at the time that silicone based brake fluids wouldn't end up being all that great and they'd have limited acceptance. Then, when an improved standard for the glycol based fluids (DOT3 and 4) came out, they choose, again in their great wisdom, to designate it 5.1. And a world of confusion was born. Suffice to say, 5 or 5.0 fluids are very different from 3, 4, and 5.1 and the two types should never be mixed. Also, even if you completely disassembled and cleaned your brake system of all trace of the glycol based 3, 4, or 5.1, you still don't want to use the silicone based 5.0.

Bottom line......5.1 gets you higher dry and wet boiling points. Usually. Sometimes DOT3/4 fluids exceed DOT 5.1 standards. A good one is Valvoline synthetic DOT3/4. Best bet is to read the labels and check the specifications.

Also, some brake fluids are a little more viscous than others and are, as a result, not suitable for use in ABS systems. Again, read the labels.

'Hope that helps.

 

[Dan Kyle]

DOT 3/4 and DOT 5.1 are the same chemistry. Just as DOT 4 was an improvement over DOT 3 (often sold as DOT 3/4 because it meets both specs - just a marketing call), DOT 5.1 is an improvement over DOT 4. Most of the time, these improvements are higher dry and wet boiling points. And because the chemistry is pretty much the same, all the various DOT 3,4, and 5.1's absorb moisture at pretty much the same rate, though some absorb moisture a bit faster than others.



Bottom line......5.1 gets you higher dry and wet boiling points. Usually. Sometimes DOT3/4 fluids exceed DOT 5.1 standards. A good one is Valvoline synthetic DOT3/4. Best bet is to read the labels and check the specifications.

Also, some brake fluids are a little more viscous than others and are, as a result, not suitable for use in ABS systems. Again, read the labels.

'Hope that helps.

My understanding is that DOT 5.1 is for ABS brake systems.

As far as Dot 5.1 having a higher boiling point, maybe based on the DOT spec, but it does not when compared to the better Dot 4 fluids.

Castrol SRF (590°F/518°F) Dot 4
ATE Type 200 and Super Blue Racing (536°F/392°F), Dot 4

Even a company making both has Dot 4 at a higher boiling point.

Motul RBF 600 (593°F/421°F). Dot 4

Compare these numbers to Motul 5.1 (518°F/365°F)

I will Copy this from "Shazaam" on another forum:
DOT 5.1 is a lighter viscosity glycol-based fluid that was developed for use in ABS systems that need to cycle on and off quickly. It really has no advantage over the DOT 4 fluid recommended by Ducati. DOT 5.1 fluid has worse performance after absorbing moisture.

The specification (527°F/347°F) for DOT 5.1 brake fluid has a higher minimum dry boiling point/minimum wet boiling point than the DOT 4 spec, but these are just minimum specs; some DOT 4 fluids exceed these DOT 5.1 minimums.

For example, (expensive) Castrol SRF (590°F/518°F) is used by Formula One teams, ATE Type 200 and Super Blue Racing (536°F/392°F), and Motul RBF 600 (593°F/421°F). Golden Spectro Supreme DOT 4 (520°F/367°F) comes close.

Compare these numbers to Motul 5.1 (518°F/365°F)

Most of us don't change our brake fluid very often, so wet boiling point numbers are more important. On the track, brake fade is the main concern so we change the fluid more often and use a higher dry boiling point fluid. Generally, the higher the dry boiling point, the faster the fluid absorbs moisture from the air, Castrol SRF and the ATE fluids excepted.

The reminder from Brembo:

For best braking performance, we recommend changing brake fluid twice a year. If the machine is to be stored in a damp environment (over the winter, say) , we recommend installing fresh fluid before and after the storage period. At minimum service levels, glycol brake fluids must be completely changed at intervals not to exceed a period of 18 months.

 

[ST Guy]

The specification (527°F/347°F) for DOT 5.1 brake fluid has a higher minimum dry boiling point/minimum wet boiling point than the DOT 4 spec, but these are just minimum specs; some DOT 4 fluids exceed these DOT 5.1 minimums.

That's the reason to check the specs on the can. The standards are only minimums and a DOT 4 can exceed the performance of a DOT 5.1

'Forgot about the DOT 5.1's absorbing moisture at a somewhat faster rate. But if you change once a year around here in California, you're OK.

 

[fast4d]

for magura masters use magura blood, atf or even mineral oil. don't use brake fluid.


for other masters such as brembo clutch I now use DOT5. it does not absorb water/moisture so I don't have to bleed often . aprilia's brembo masters are notorious for requiring frequent bleeds. make sure you flush out the old dot3,4,5.1 before switching.

 

[Dan Kyle]

for magura masters use magura blood, atf or even mineral oil. don't use brake fluid.


for other masters such as brembo clutch I now use DOT5. it does not absorb water/moisture so I don't have to bleed often . aprilia's brembo masters are notorious for requiring frequent bleeds. make sure you flush out the old dot3,4,5.1 before switching.

I am not sure why people do not seem to believe what the MANUFACTURES of each of these products recommend.

If Brembo recommends Dot 4 use Dot 4, do not use Dot 5.

Just above with Magura, they say on their website NOT to use off the shelf Mineral Oil, it is not the same as what they are recommending, yet he recommended it anyway.

If, insert motorcycle manufactures name here, recommend Dot 4 use Dot 4.

If you do not have ABS, do not use Dot 5.1.

In some cases the result of using the wrong fluid may not have a major effect, as is the case with using Dot 5.1 instead of Dot 4, but why do it??

Recommending Dot 5 because it does not absorb moisture, to me, does not seem like a good recommendation. Just maybe the Dot 4 is designed to absorb moisture, why, to keep the moisture from corroding the internal parts so they do not seize, and stop working.

Isn't it amazing how few brake system failures you hear about, do you ever wonder why?

 

[fast4d]

I was referring to what the OP was - clutch systems. not brake.

for brakes I use what the manual/manufacturer recommends (dot4 or 5.1)

my magura KTM equipped says:

mineral oil on the lid

manual says 'hydraulic mineral oil'

unless you're adding water with dot 5 and leaving it in for years, I don't see how you clutch actuation parts can seize.

 

[arnoha]

DOT 5 will not absorb moisture. That's a BAD thing.

Yes, as glycol based hydraulic fluids absorb moisture, their boiling points go down. As DOT 5 does not absorb moisture, it's boiling point will not move.

Here's the big 'but': Not absorbing the moisture doesn't make it go away. Any moisture that enters the system is still there. Since these mineral oil based fluids are lighter than water, the water descends to the caliper. Your effective boiling point just became the boiling point of water. That the DOT 5 is not boiling is completely irrelevant.

Do NOT use DOT 5 on motorcycles. Ever. It's very risky.

EDIT: I see that you're referring to the clutch. In that case...use what the manufacturer recommends. What is the point of converting a glycol fluid to mineral oil? Especially on a clutch?

 

[Dan Kyle]

I was referring to what the OP was - clutch systems. not brake.

for brakes I use what the manual/manufacturer recommends (dot4 or 5.1)

my magura KTM equipped says:

mineral oil on the lid

manual says 'hydraulic mineral oil'

unless you're adding water with dot 5 and leaving it in for years, I don't see how you clutch actuation parts can seize.

Take a look here about Mineral oil as well as Magura statement.

http://www.peterverdonedesigns.com/bikemineraloil.htm

That is says "hydraulic" is a clue that you should not be using just any mineral oi, as well as telling you not to use a DOT type brake fluid. I would guess that is there to meet a federal requirement.
I would think in the owners manual it is more specific as to what Hydraulic Mineral oil they are refering to.

As far as what in a Clutch system could suffer, let me offer my opinion:
Lets start with the mastercylinder, it is in design the same as a brake mastercylinder, usually Clutch Mastercylinders pistons are smaller, the piston and outer housing are anodized aluminum, it will corrode, look at Motorcycles that are left outside in areas that get a lot of fog, like where I am in the Monterey area.

Same with the slave cylinder, in design it really is no different than a brake caliper, the brake caliper is the brake slave cylinder.
On some Clutch slaves, the pistons are aluminum, most brake caliper are a hard chromed steel. Both are subject to corrosion.

Water is heavier than the oils used in the clutch or brake systems, so it tends to collect at the slave cylinder.
So you usually see the failure at the slave cylinder.
The water gets into the system thru the vent system in the fluid reservoir, if water were unable to get into the system, there would not be a need to make the fluids absorb the water in the first place.