Clutch fluid - Motorcycle-Journal Forums

CheapBike · 03-15-2008, 11:29 AM

I need to bleed my brake & clutch today, heard rumor they both use brake fluid.

Can anyone confirm, or give suggestions?

omegajim · 03-15-2008, 11:40 AM

what, no owner's manual?

the clymer manual for my 1984 magna says "use dot 3 or 4 on the 700 - 750 models and only dot 4 for 1100 cc or larger models"

if that's any indicator.

frostbitevinnie · 03-15-2008, 12:56 PM

Yep, both the same. Essentially a hydraulic oil. Hydraulic brakes, hydraulic clutch.

omegajim · 03-15-2008, 08:59 PM

I would use dot 4, because the primary difference between dot 4 and dot 3 is the boiling point, dot 4 being higher.

Ordinarily, this wouldn't matter, excepting for the fact that brake fluid is hydroscopic (yeah, it took me awhile too, it means it absorbs water).

So, that all said, I would use dot 4, and in the event it absorbs water from the air (it will) the dot 4 will have to be hotter to boil over than dot 3 fluid.

The odds your brake fluid (much less clutch fluid) will ever get this hot under normal conditions? Unlikely.

Also, for the record, dot 5, silicone based. NEVER use unless specified. Never, and did I mention NEVER?

good luck with the honda, ride far.

CheapBike · 03-17-2008, 09:45 PM

Thanks guys. Now I've just got to figure out this fancy mity vac thing.

omegajim · 03-17-2008, 11:39 PM

you shouldn't even need a fancy mighty vac thing.

although it is tricky, and you may need an assitant, proceed as follows.

with a wrench on the bleeder valve (and a tube attached to that going into a jar of fluid) open valve.

pump clutch (upon pulling in clutch)
close bleeder valve.

release clutch lever.

rinse and repeat.

just like bleeding the brakes, if I recall.

CheapBike · 03-18-2008, 02:21 AM

Oh crap, trusted the guy at pepboys. I asked for dot4 as you recommeded omegajim and he said this stuff exceeeded dot 3 and 4 specifications.

It's castrol GTLMA brake fluid and I don't think based on the specs it's either. My bike's on hold for reasons other than the hydraulic fluid but if anyone knows if this stuff is a go or no, I'd appreciate it.

It does say it mixes with conventional brake fluids, which leads me to believe it's not conventional, ie synthetic. They didn't have dot 4 in stock but I'll pay for it, obviously.

omegajim · 03-18-2008, 01:00 PM

the label should say what it's compatible with.

castrol wouldn't be selling something they wouldn't stand behind.

as long as it's not silicone based.

wildwolf · 03-18-2008, 04:03 PM

Valvoline Synthetic DOT 4 is what I use. Great stuff.

03-15-2008, 11:29 AM	#1 (permalink)
CheapBike In Training Joined: Jul 2007 Bike: 88 Honda VF750 Supermagna Location: Utah Posts: 110	Clutch fluid I need to bleed my brake & clutch today, heard rumor they both use brake fluid. Can anyone confirm, or give suggestions?

03-15-2008, 11:40 AM	#2 (permalink)
omegajim M-J.Com Lifetime Achievement Award Joined: Jan 2007 Bike: 1980 Yamaha XS850 Location: Washington County, WI Posts: 6,544	what, no owner's manual? the clymer manual for my 1984 magna says "use dot 3 or 4 on the 700 - 750 models and only dot 4 for 1100 cc or larger models" if that's any indicator. __________________ "FREE TIBET!"* With purchase of one Tibet of equal or greater value.

03-15-2008, 12:56 PM	#3 (permalink)
frostbitevinnie In The Zone Joined: Jul 2007 Bike: 07' C90T 76' MT250 Location: 3rd house NW of the Depot Posts: 2,727	Yep, both the same. Essentially a hydraulic oil. Hydraulic brakes, hydraulic clutch. __________________ I set up a by knot of soups that valid terrific, and can be made in big batches and frozen. Is there any interest? Karri Tamsin

03-15-2008, 08:59 PM	#4 (permalink)
omegajim M-J.Com Lifetime Achievement Award Joined: Jan 2007 Bike: 1980 Yamaha XS850 Location: Washington County, WI Posts: 6,544	I would use dot 4, because the primary difference between dot 4 and dot 3 is the boiling point, dot 4 being higher. Ordinarily, this wouldn't matter, excepting for the fact that brake fluid is hydroscopic (yeah, it took me awhile too, it means it absorbs water). So, that all said, I would use dot 4, and in the event it absorbs water from the air (it will) the dot 4 will have to be hotter to boil over than dot 3 fluid. The odds your brake fluid (much less clutch fluid) will ever get this hot under normal conditions? Unlikely. Also, for the record, dot 5, silicone based. NEVER use unless specified. Never, and did I mention NEVER? good luck with the honda, ride far. __________________ "FREE TIBET!"* With purchase of one Tibet of equal or greater value.

03-17-2008, 11:39 PM	#6 (permalink)
omegajim M-J.Com Lifetime Achievement Award Joined: Jan 2007 Bike: 1980 Yamaha XS850 Location: Washington County, WI Posts: 6,544	you shouldn't even need a fancy mighty vac thing. although it is tricky, and you may need an assitant, proceed as follows. with a wrench on the bleeder valve (and a tube attached to that going into a jar of fluid) open valve. pump clutch (upon pulling in clutch) close bleeder valve. release clutch lever. rinse and repeat. just like bleeding the brakes, if I recall. __________________ "FREE TIBET!"* With purchase of one Tibet of equal or greater value.

03-17-2008, 09:45 PM	#5 (permalink)
CheapBike In Training Joined: Jul 2007 Bike: 88 Honda VF750 Supermagna Location: Utah Posts: 110	Thanks guys. Now I've just got to figure out this fancy mity vac thing.

03-18-2008, 02:21 AM	#7 (permalink)
CheapBike In Training Joined: Jul 2007 Bike: 88 Honda VF750 Supermagna Location: Utah Posts: 110	Oh crap, trusted the guy at pepboys. I asked for dot4 as you recommeded omegajim and he said this stuff exceeeded dot 3 and 4 specifications. It's castrol GTLMA brake fluid and I don't think based on the specs it's either. My bike's on hold for reasons other than the hydraulic fluid but if anyone knows if this stuff is a go or no, I'd appreciate it. It does say it mixes with conventional brake fluids, which leads me to believe it's not conventional, ie synthetic. They didn't have dot 4 in stock but I'll pay for it, obviously.

03-18-2008, 01:00 PM	#8 (permalink)
omegajim M-J.Com Lifetime Achievement Award Joined: Jan 2007 Bike: 1980 Yamaha XS850 Location: Washington County, WI Posts: 6,544	the label should say what it's compatible with. castrol wouldn't be selling something they wouldn't stand behind. as long as it's not silicone based. __________________ "FREE TIBET!"* With purchase of one Tibet of equal or greater value.

03-18-2008, 04:03 PM	#9 (permalink)
wildwolf Fourth gear and illegal Joined: Jan 2006 Bike: 1999 vs800 intruder Location: Delta Junction, AK Posts: 705	Valvoline Synthetic DOT 4 is what I use. Great stuff. __________________

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