Mission Statement
The K.M.C. Cycling Club is a diverse group of people from across the Kaiserslautern Military Community (KMC) brought together by a common interest in cycling and cycling advocacy. Whether through racing, group rides, community involvement or social events centered on cycling, K.M.C. Cycling's primary purpose is to further the sport of cycling in the KMC, and provide a valuable cycling outlet to its members. We are a not-for-profit organization that values diversity, friendship and, above all, a good ride.
The K.M.C. Cycling Club is a diverse group of people from across the Kaiserslautern Military Community (KMC) brought together by a common interest in cycling and cycling advocacy. Whether through racing, group rides, community involvement or social events centered on cycling, K.M.C. Cycling's primary purpose is to further the sport of cycling in the KMC, and provide a valuable cycling outlet to its members. We are a not-for-profit organization that values diversity, friendship and, above all, a good ride.
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DOT 5.1 from Finish Line...Good or Bad
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spookyload
powerpro369
6 posters
Page 1 of 1
DOT 5.1 from Finish Line...Good or Bad
I am getting ready to shorten the brake hose on my Hope brakes but I will need to do a bleed afterwards. I founds some brake fluid by Finish Line at Outdoor Rec. that states it is compatible with all brakes using DOT 3, 4 & 5.1. Apparently, it has the boiling point of 5.1 fluid. I am normally pretty hesitant when purchasing anything that claims that it is multi-compatible. Has anyone used this brake fluid before or should I go with something that is specifically DOT 5.1? I am guessing that 5.1 can go into any brake system, except the mineral oil style brakes, but 3 or 4 cannot go into 5.1 brakes. I imagine the main difference between 3, 4 and 5.1 is the boiling temp. Can anyone enlighten me on this? Should I steer away from Finish Lines multi-compatible fluid?
powerpro369- Posts : 206
Join date : 2011-04-07
Age : 43
Location : Ramstein
Re: DOT 5.1 from Finish Line...Good or Bad
Just because you shorten your lines, doesn't mean you will need to bleed them. Just be careful when you cut the line and not press the lever. It is amazing how little fluid you will lose.
spookyload- Posts : 1167
Join date : 2010-11-21
Age : 55
Location : Vogelweh, Germany
Re: DOT 5.1 from Finish Line...Good or Bad
powerpro369 wrote: I imagine the main difference between 3, 4 and 5.1 is the boiling temp. Can anyone enlighten me on this?
Boiling point is only one factor, the main issue is weather it's compatible with the seals and O-rings of your system...
Zenkem- Posts : 1818
Join date : 2010-11-20
Age : 56
Location : Hermersberg
Re: DOT 5.1 from Finish Line...Good or Bad
^ what he said. I wouldn't take any chances other than the specified DOT 5.1. I found some at ATU in Kaiserslautern for cheap. There's one in Homburg, too. Probably any auto shop will have it, if I remember right it's called Bremsenflussigkeit. Brand should not matter.
Matt is also correct. Remove the pads and press the pistons against a small spacer to put max volume of fluid in your calipers. Remove the hose, remove the insert and slide the olive back, cut, replace the insert and slide the olive forward to about 3/16" from the end, reinstall. Press the pistons into the calipers to push any bubble that may have formed past the master cylinder and into the reservoir... Hopes have an open-style reservoir, making this type of reverse-bleed possible. Personally, I prefer to back-flush a syringe of fluid from the bleed nipple to the reservoir. Might as well, since you're already working on the brake system.
Matt is also correct. Remove the pads and press the pistons against a small spacer to put max volume of fluid in your calipers. Remove the hose, remove the insert and slide the olive back, cut, replace the insert and slide the olive forward to about 3/16" from the end, reinstall. Press the pistons into the calipers to push any bubble that may have formed past the master cylinder and into the reservoir... Hopes have an open-style reservoir, making this type of reverse-bleed possible. Personally, I prefer to back-flush a syringe of fluid from the bleed nipple to the reservoir. Might as well, since you're already working on the brake system.
eurotrash- Officer
- Posts : 786
Join date : 2010-11-28
Age : 47
Location : Granny Gear (ಠ益ಠ)
Re: DOT 5.1 from Finish Line...Good or Bad
Thank you to all of you that sent me your opinion. I think I will try and locate some legit 5.1. I figure, even if I don't need it now I will in the future.
powerpro369- Posts : 206
Join date : 2011-04-07
Age : 43
Location : Ramstein
Re: DOT 5.1 from Finish Line...Good or Bad
Just remembered that my neighbor gave me a bottle of brake fluid for his motorcycle when he PCSd. It might be 5.1. I will never use it so I will check it out when I get back Friday. It is yours if it is 5.1 since my brakes all use mineral oil.
spookyload- Posts : 1167
Join date : 2010-11-21
Age : 55
Location : Vogelweh, Germany
Re: DOT 5.1 from Finish Line...Good or Bad
That would be great. Thank you very much
powerpro369- Posts : 206
Join date : 2011-04-07
Age : 43
Location : Ramstein
Re: DOT 5.1 from Finish Line...Good or Bad
I was interested myself, so I read through 49 CFR §571.116, Motor vehicle brake fluids. Also read la Wikipedia, FWIW...
The Red Line 3-4-5.1 oil is good to use. Except in some formulations regarding viscosity at -40F, all 5.1 fluids meet DOT 3 and 4.
There are variances in formulation from one manufacturer to the next. I would bet money on the motorcycle fluid being better for our bikes, since motorcycle and mountain bike calipers get hotter than car brakes. The tradeoff is in the viscosity, when the wet boiling point goes up, so does the viscosity. Our brakes with their small parts would respond better on both application and retraction with lower viscosity fluids. I really couldn't say what is best in that range, but the closer to the maximum spec the 5.1 fluid is (900 mm/s) the better. DOT 4 runs more like 1500 mm/s, but has a lower BP.
I have DOT 4 in my older Hope 4-piston brakes, and DOT 5.1 in my late-model Hope 2-piston brakes. Strangely, with the same 183mm rotors, I experience less fade with the DOT 4 system... but it could just mean that the DOT 5.1 fluid has taken on water from diffusing past the seals because I have ridden that bike through so much wet weather since changing it last (not to mention storing the bikes in the cellar where the humidity is high). The water portion boils out of fluid with water absorbed in it and makes brakes spongy and draggy at the caliper while they are hot from a ripping descent... like the kind that turn your rotors gold and blue.
So change your fluid more often... I am going to do mine when I get home, and every 6 months instead of every year from now on. Fight brake fade.
There's four more cents on top of my first two.
The Red Line 3-4-5.1 oil is good to use. Except in some formulations regarding viscosity at -40F, all 5.1 fluids meet DOT 3 and 4.
There are variances in formulation from one manufacturer to the next. I would bet money on the motorcycle fluid being better for our bikes, since motorcycle and mountain bike calipers get hotter than car brakes. The tradeoff is in the viscosity, when the wet boiling point goes up, so does the viscosity. Our brakes with their small parts would respond better on both application and retraction with lower viscosity fluids. I really couldn't say what is best in that range, but the closer to the maximum spec the 5.1 fluid is (900 mm/s) the better. DOT 4 runs more like 1500 mm/s, but has a lower BP.
I have DOT 4 in my older Hope 4-piston brakes, and DOT 5.1 in my late-model Hope 2-piston brakes. Strangely, with the same 183mm rotors, I experience less fade with the DOT 4 system... but it could just mean that the DOT 5.1 fluid has taken on water from diffusing past the seals because I have ridden that bike through so much wet weather since changing it last (not to mention storing the bikes in the cellar where the humidity is high). The water portion boils out of fluid with water absorbed in it and makes brakes spongy and draggy at the caliper while they are hot from a ripping descent... like the kind that turn your rotors gold and blue.
So change your fluid more often... I am going to do mine when I get home, and every 6 months instead of every year from now on. Fight brake fade.
There's four more cents on top of my first two.
eurotrash- Officer
- Posts : 786
Join date : 2010-11-28
Age : 47
Location : Granny Gear (ಠ益ಠ)
Re: DOT 5.1 from Finish Line...Good or Bad
eurotrash wrote:I was interested myself, so I read through 49 CFR §571.116, Motor vehicle brake fluids. Also read la Wikipedia, FWIW...
The Red Line 3-4-5.1 oil is good to use. Except in some formulations regarding viscosity at -40F, all 5.1 fluids meet DOT 3 and 4.
There are variances in formulation from one manufacturer to the next. I would bet money on the motorcycle fluid being better for our bikes, since motorcycle and mountain bike calipers get hotter than car brakes. The tradeoff is in the viscosity, when the wet boiling point goes up, so does the viscosity. Our brakes with their small parts would respond better on both application and retraction with lower viscosity fluids. I really couldn't say what is best in that range, but the closer to the maximum spec the 5.1 fluid is (900 mm/s) the better. DOT 4 runs more like 1500 mm/s, but has a lower BP.
I have DOT 4 in my older Hope 4-piston brakes, and DOT 5.1 in my late-model Hope 2-piston brakes. Strangely, with the same 183mm rotors, I experience less fade with the DOT 4 system... but it could just mean that the DOT 5.1 fluid has taken on water from diffusing past the seals because I have ridden that bike through so much wet weather since changing it last (not to mention storing the bikes in the cellar where the humidity is high). The water portion boils out of fluid with water absorbed in it and makes brakes spongy and draggy at the caliper while they are hot from a ripping descent... like the kind that turn your rotors gold and blue.
So change your fluid more often... I am going to do mine when I get home, and every 6 months instead of every year from now on. Fight brake fade.
There's four more cents on top of my first two.
Zenkem- Posts : 1818
Join date : 2010-11-20
Age : 56
Location : Hermersberg
Re: DOT 5.1 from Finish Line...Good or Bad
Um,
simply, DOT 5.1 from Finish Line = Good
Been using for 3 years now, with better fade resistance then whatever comes in Avid brakes from the factory.
simply, DOT 5.1 from Finish Line = Good
Been using for 3 years now, with better fade resistance then whatever comes in Avid brakes from the factory.
PB Matrix- Posts : 215
Join date : 2011-06-13
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