Dot 5 (Silicone) brake fluid?

[Tropic-al]

Does anyone have pros/cons to using Dot 5 brake fluid in the 11's?
I was told not to do it because it COULD cause a problem in the old aluminum brake calipers.
I changed the rear fluid to Dot 5 and after about 300 miles, while on a ride, the caliper would not release, thus overheating and locking up. After it cooled off (?) it loosened up and I rode it back home without using the rear brake. Putting it on the center stand, turning the wheel by hand and pressing the lever it seemed to work normaly. Then I kept some pressure on the lever and it went down like the pedal would in a car when your master cilinder goes bad.
Any ideas? Think it has something to do with the Dot 5 or just a coincidence?

[tarzan]

I use dot 5.It supercedes the older stuff and it is the only grade available here.
I would bet you need to disassemble and clean calipers and masters.
As far losing pedal,that is probably like you thought, the master needs a rebuild.

[Pat Kelly]

DOT 5 is not compatible with DOT 3. The complete system needs to be disassembled and cleaned of all traces of DOT 3 (including the inside of the brake hose(s) ).
Even then vintage parts, like NOS hoses and rebuild kits, may react negatively to DOT 5.

[XSokieSPECIAL]

Does anyone have pros/cons to using Dot 5 brake fluid in the 11's?
I was told not to do it because it COULD cause a problem in the old aluminum brake calipers.
I changed the rear fluid to Dot 5 and after about 300 miles, while on a ride, the caliper would not release, thus overheating and locking up. After it cooled off (?) it loosened up and I rode it back home without using the rear brake. Putting it on the center stand, turning the wheel by hand and pressing the lever it seemed to work normaly. Then I kept some pressure on the lever and it went down like the pedal would in a car when your master cilinder goes bad.
Any ideas? Think it has something to do with the Dot 5 or just a coincidence?

This might be interesting reading for you Tropic-al..........

http://www.motorcycleproject.com/mot...rakefluid.html

[Tropic-al]

My bad !!!

Thanks Tarzan.
Just FYI, dot 5.1 is not silicone based, so its safe to use. Dot 5 is, and apparently it is what causes the problem.

Thanks Pat.
I definitely did not do a thorough cleaning of all the dot 3 fluid like you mentioned. I should have heeded the warning about it possibly affecting the aluminum calipers.
I guess a rebuild of M/C and caliper is in order. For sure I'll use dot 3 or 4.

[DGXSER]

There is an article in either the tech tips or the FAQ about the isue of DOT 5 and DOT 3 or DOT 4 fluids. The issue appears to be more of combining the two types of fluid. Like PAT stated, the two fluids will not play nice together so you need to get all of the old out before adding the new.

I am no expert and certainly do not know for sure, but I doubt there is any issue with the fluid and the metals involved. The rubber even seems unlikely to be an issue. JMHO

[petejw]

You should be sweet in flushing the system out with
dot 3, i doubt you would need to rebuild the calipers or m/c,
the fluids dont mix together, but it shouldnt effect
any of the rubbers.

[Tropic-al]

Thanks XSokie

Enlightening article.
Another learning experience!!

[XSokieSPECIAL]

Enlightening article.
Another learning experience!!

Welcome....... bottom line is standard dot 3/4 fluid is really all you need. The dot 5.1 has a higher boiling point but is not neccesary in our application.

Just flush it every couple of years. Your hydraulics will last virtually forever.

Dot 5 if you run NASCAR and want to replace it A LOT!

Postal vehicles used to run dot 5 because of thier stop and go life but it was changed at regular intervals.

Your tax dollars at work. Not to mention the price of stamps.

[cywelchjr]

Welcome....... bottom line is standard dot 3/4 fluid is really all you need. The dot 5.1 has a higher boiling point but is not neccesary in our application.

I'm not sure, I have DOT 4 in mine, and when the temps are over 115 in situations with lots of stop and go the brakes will go spongy on me.

Just flush it every couple of years. Your hydraulics will last virtually forever.

I'm not so sure about that. After reading the owners manual this week, Yamaha says all seals should be replaced at least every 2 years, and the flexible lines should be replaced at least every 4 years. I know that they seem to be doing ok (no leaks and all) but then I suspect mine was bled regularly, but according to the schedule all the seals should have been replace 14 times by now and the flex lines 7 times, and I'm pretty sure that at least the flexible lines are the originals, I plan on doing something about that before summer gets here, and since I run sintered pads, I'll probably go with DOT 5.1 for the higher boiling point.

Dot 5 if you run NASCAR and want to replace it A LOT!

Postal vehicles used to run dot 5 because of thier stop and go life but it was changed at regular intervals.

Your tax dollars at work. Not to mention the price of stamps.

Have spent 7 years in the Army I'm not only not surprised, I'm almost shocked that they didn't replace the entire brake system each time they did it.

[Rasputin]

This is what it looks like when you mix Dot 5 and Dot 3. I mixed in more Dot 3 and it went back to fluid state for a while. I did not get around to changing the brake system yet and now it is looking sorta like pudding.

[XSokieSPECIAL]

I'm not sure, I have DOT 4 in mine, and when the temps are over 115 in situations with lots of stop and go the brakes will go spongy on me.

I don't think that will be because of brake fluid boil cy. Most likely some runout in the rotor due to heat, pushing the piston back in a little further than usual. That rotor would pretty much have to be glowing red to boil the brake fluid in that extremely well ventilated caliper.

I'm not so sure about that. After reading the owners manual this week, Yamaha says all seals should be replaced at least every 2 years, and the flexible lines should be replaced at least every 4 years. I know that they seem to be doing ok (no leaks and all) but then I suspect mine was bled regularly, but according to the schedule all the seals should have been replace 14 times by now and the flex lines 7 times, and I'm pretty sure that at least the flexible lines are the originals, I plan on doing something about that before summer gets here, and since I run sintered pads, I'll probably go with DOT 5.1 for the higher boiling point.

I'm sure Yamaha enjoyed selling parts. Henry Ford did too.

That is why he sold the Model T so cheap. He knew he would make his money back on parts.

Truth is motocycle brake parts are no more susceptible to damage than automobile brake parts.

IF they are properly maintained.

Dot 5.1 is unquestionably superior to dot 3/4 as far as temp. goes but IMHO unnessesary.

[XSokieSPECIAL]

This is what it looks like when you mix Dot 5 and Dot 3. I mixed in more Dot 3 and it went back to fluid state for a while. I did not get around to changing the brake system yet and now it is looking sorta like pudding.

OOPS!!!!

[Rasputin]

OOPS!!!!

I did not do it but yup thats an oops. Kinda interesting to watch it change over the weeks. Once I get new S/S brake lines for that bike I will be rebuilding everything from brake handle to speed bleeders. Still have to finish up the 78E I have apart first as well so I will get to see more changes. I have left the lid loose so it changes more rapidly.

[wa407mpp]

Brake fluid is rated by boiling it's point, the higher the boiling point the higher the number, but also the higher the boiling point the quicker it will absorb moisture. That is why it is usually reserved for hard use applications.