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The manual says Dot 4. I have some unopened in-date Dot 5.1 on the shelf.
Is that ok to use and what's actually the difference?
Oh yes...I guess i should apologise up front if this question was already answered in June 2016 and/or is a daft thing to ask.
:)
 

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Many threads on this subject.

Everyone, please search before posting. If you don't find what you are looking for or don't understand the content then a new thread is good. Searching is actually great to cross-reference information and to stumble upon associated subjects. Learning how to maintain your bike in this manner is actually a fun process. I implore more members to take a few moments during your inquiries to take the initiative. That said new posts are fine, use Dot 4 unless heavy track use.
 

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DOT 5.1 and DOT 4 are compatible. It is the DOT 5 that is silicone based and cannot be mixed with the others.

Use your 5.1 .... It will be fine.

A Google search will send you to technical web sites where you can study the pros and cons of different brake fluids, and what specs in brake fluid are what.
Wet boiling temp is a key question if you use your brakes hard (like racing). ALL brake fluid should be replaced every 2 years regardless.
 

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Main difference is Dot 5/5.1 has a higher boiling point, it's a must on the rear brake on many MV's. Some say it eats seals, but I've always used dot 5.1 and never had an issue with that!! It's mainly used for heavy braking and where I used to do frequent track days it was my fluid of choice. No real difference in braking performance except that the dot 5/5.1 will help prevent brake fade with heavy use or high temps (i.e rear brake near exhaust on many MV's) so if you have dot 5.1 already, just get all the old fluid out of your system and replenish with Dot 5.1 Job done! :) (y)
 

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Dot 5/5.1 :) (y)
DOT 5 and DOT 5.1 are not at all the same thing. DOT 5 is a silicone based fluid totally incompatible with other brake fluids. It's primary benefit is it will not damage paint and plastic when spilled like other brake fluids. It is also hydrophobic so it doesn't absorb water which can be problematic in its own way.

Dot 5.1 can be mixed with DOT 4 or 3.... Different brands of brake fluids have different characteristics and dry/wet boiling points. They certainly are NOT all the same thing. DOT 3 is an obsolete spec. DOT 4 is what most manufacturers recommend. DOT 5.1 does have a higher boiling point in base form.

Here is some good basic info:
 

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DOT 5 and DOT 5.1 are not at all the same thing. DOT 5 is a silicone based fluid totally incompatible with other brake fluids. It's primary benefit is it will not damage paint and plastic when spilled like other brake fluids.

It is also hydrophobic so it doesn't absorb water which can be problematic in its own way.
Which makes it (DOT 5) the logical choice for vehicles sitting in a collection that are rarely, if ever, driven.
 

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DOT 5 and DOT 5.1 are not at all the same thing. DOT 5 is a silicone based fluid totally incompatible with other brake fluids. It's primary benefit is it will not damage paint and plastic when spilled like other brake fluids. It is also hydrophobic so it doesn't absorb water which can be problematic in its own way.

Dot 5.1 can be mixed with DOT 4 or 3.... Different brands of brake fluids have different characteristics and dry/wet boiling points. They certainly are NOT all the same thing. DOT 3 is an obsolete spec. DOT 4 is what most manufacturers recommend. DOT 5.1 does have a higher boiling point in base form.

Here is some good basic info:
All good info. Thanks Ed the brake fluid guru ;) I still maintain the main benefit/difference is the higher boiling point and I personally never mix any brake fluid, would always change the lot out in one go and clean reservoir, avoids any contamination with old or dirty fluid. Just my personal opinion, but appreciate it is possible to mix. I've always used Dot 5.1, great stuff! I have however also learnt a bit from your superior knowledge Ed, thank you kindly ole bean :) (y)
 

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Which makes it (DOT 5) the logical choice for vehicles sitting in a collection that are rarely, if ever, driven.
Actually not....water will condense in the system (I know, it is sealed, but it happens regardless) and any water will collect at a low point and cause corrosion. Best to have water absorbency, even if you don't change the fluid every few years because the bike is sitting unused.
 

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Actually not....water will condense in the system (I know, it is sealed, but it happens regardless) and any water will collect at a low point and cause corrosion. Best to have water absorbency, even if you don't change the fluid every few years because the bike is sitting unused.
Doubtless Ed knows more on the subject and I would welcome amplification for him, but I have seen substantial brake caliper piston corrosion from letting a bike sit unused. Even my Brutale, that was on the dealer showroom for about 18months before I bought it (otherwise new) had some corrosion in the master. When I store my bikes, One of the things I consider essential, is to change the brake and clutch fluid every couple of years at least. Ed, what say you? Why the counsel for leaving brake fluid sit in stored bikes?
 

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Why the counsel for leaving brake fluid sit in stored bikes?
I don't !!! But if you are going to let your bike sit stored for a long period I don't recommend DOT5 fluid as it will allow all moisture that may be or get into the system to accumulate at a single low point.
If you flush with fresh brake fluid before storage, and store in a climate controlled atmosphere (low humidity and minimal temperature swings) then fluids will last many years (not gasoline!!).
Barber Motorsports Museum does not run about flushing brake fluid in their collection routinely....and believe me, they take very good care of their bikes. Every bike on display can be up and running with minimal work if needed.
 

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I don't !!! But if you are going to let your bike sit stored for a long period I don't recommend DOT5 fluid as it will allow all moisture that may be or get into the system to accumulate at a single low point.
If you flush with fresh brake fluid before storage, and store in a climate controlled atmosphere (low humidity and minimal temperature swings) then fluids will last many years (not gasoline!!).
Barber Motorsports Museum does not run about flushing brake fluid in their collection routinely....and believe me, they take very good care of their bikes. Every bike on display can be up and running with minimal work if needed.
Yeah, I understood the Dot 5 observation for sure. Interesting and reassuring regarding the Barber storage. Do they do anything like fog the cylinders etc? I presume they drain the gas? Or fill it to avoid condensation, then drain and replace to prep for running? Thanks in advance for your knowledge!
 

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Barber's fuel systems are dry and batteries are removed. If you aren't familiar with the Museum and park, have a read:
 
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