clutch hydraulic fluid

[T Legg]

I thought I had a slipping clutch for a year instead of a bad second and third gear so i ran a double clutch spring with a stock master cylinder on my 84 FJ1100 .i pulled the second spring out but the clutch now didn't fully release. I rebuilt the master cylinder because it started to leak and then found out how bad my clutch handle was.I'm glad i don't need the double spring.            I know everything I've ever seen has said you absolutely can not use dot 5 in a (dot 3,dot 4,dot 5.1)  system but after reading a a post from an engineer who restores and maintains his own vintage triumph cars i am tempted to try it with my clutch. does anyone have experience with this?

[T Legg]

the web site was http://www.buckeyetriumphs.org/technical/Brakes/Fluid/Fluid.htm  that discussed the use of dot 5

[FJmonkey]

I have been using Dot 5 in my clutch for a few years now. I flushed out every part of the system to clean out the Dot 3. I should drain it now and check for water. Since Dot 5 will not absorb it like Dot 3. Performance seems the same as before.

[T Legg]

   my main reason to do it would be to save my fairing,but when i went to fix my master cylinder leak my fluid looked like chocolate milk and none of the seals showed any damage the cylinder is like a mirror all the parts had been replaced less than a year ago.i think it may have leaked because the fluid was so degraded ,in less than a year also.I,m glad to know its been done allready.

[T Legg]

Let me know if you find water pooling in the slave or water corrosion in your cylinder. It would be nice to establish that it is safe to use, maybe even for brakes at some point.I havent added fluid since the master rebuild yet so i am going to do dot 5 in the clutch.

[Pat Conlon]

Hey Travis, I've had DOT 5 in my '84 for 20+ years, no corrosion problems yet, but then again, I live in the desert.
The front brake lever is firmer with DOT 3, a tad bit softer with DOT 5, but I'm used to it.
I had a '92 with DOT 3 running the exact same brake system as my '84, so I had a good side by side comparison.

You are correct to be concerned with water collecting in your DOT 5 system. DOT 5 is lighter than water and non hygroscopic so water can pool at the bottom of the slave/caliper chambers. A casual bleed will not remove the water because the bleed nipple is located at the top of the chambers and designed to remove air which collects at the top and not any water which is pooled at the bottom.
What I do every two years is to remove the calipers (leave the lines connected) and zip tie the calipers upside down and let it sit that way for a good 3-4 days. With the calipers now upside down, any water will slide to the top of the chamber where I open the bleeder (now pointing down) and suck it out with my MityVac.
I do the same with my slave.
When converting from DOT 3 to 5 it's important to open everything up and clean out any old residue. Simple flush bleed will not do this. Of course when ever you open up the calipers, plan on new seals. I never re-use old piston seals. IMHO not worth it.

Gary Foreman, the founder of fj1100.com  had a bad experience with DOT 5 corroding his slave.
He did not use the Conlon technique in removing moisture. Click on the "rebuilding the clutch slave"
http://www.fj1100.com/main.htm

If I lived in a wet climate or rode a lot in the rain, I would not recommend DOT 5.

[ribbert]

Pat, do you really go through all that rigmarole with the calipers and do you still remove your rotors regularly to roughen up the faces?

Noel

[Pat Conlon]

It's really no big deal on the calipers. Gives me a chance to get a good look at the pads.
The rotors I scrub only when I change pad compounds, like going from organic pads to HH sintered pads (the transfer layer is incompatible)

[Tuned forks]

Pat, even though rotors are often soft cast iron, I've found them to be rather hard.  What do you use to scuff the rotors effectively?

Joe

[Tuned forks]

With regard to DOT 5 brake fluid, I learned something very important about it twenty years ago.  I tried using DOT 5 in a '69 Corvette.  Unfortunately I neglected to read the label before pouring in the first quart.  The instructions indicated that air bubbles were entrained by the brake fluid and that the fluid should be heated to just over a boil to release the air bubbles.  Now some of you may call BS here but read on.  I heated the second quart but the first quart was already in the system.  I then drove from SF to Reno, which passes over a 7000' elevation at the Donner Summit.  As I drove up increasing altitude my brake pedal became increasingly lower.  The air bubbles were being released from the fluid due to the lesser atmospheric pressure.  By the time I reached the summit I had no brake pressure.  Fortunately the car had a high compression big block and I used that compression to slow me down on the eastern/downhill section of I80.  By the time I got to Reno I had a brake pedal again although it was low and during the ensuing Hot August Nights event the brake pedal came back up to the top.  My return trip home was uneventful.  Soooo, be careful with DOT 5.  Perhaps if I had put more miles on the car before going up in elevation, the brake system would not have become filled with air bubbles.  Maybe not.  Travis, I hear you about saving the fairing.  I switched just to protect the paint on that car.  Unfortunately DOT 5 used to have a lower boiling point than DOT 3 & 4.  After I lost my brakes at Laguna Seca I switched back to regular brake fluid.

Joe

[Pat Conlon]

Jeeze Louise Joe, that must have been a fun ride down the I-80 to Reno with no brakes.

......Unfortunately DOT 5 used to have a lower boiling point than DOT 3 & 4.  After I lost my brakes at Laguna Seca I switched back to regular brake fluid.

Negative my friend...DOT 5 has a higher dry and wet boiling point than regular DOT 3 or 4***

DOT 3 dry = 401*F.....Wet = 284*F
DOT 4 dry = 446*F.....Wet = 311*F
DOT 5 dry = 500*F.....Wet = 356*F

DOT 5.1 (non-silicone) has the same dry/wet boiling point as DOT 5

***ATE makes some special DOT 4 racing brake fluid I use in my Miata.
Dry = 536*F ....Wet = 388*F
http://www.ate-brakes.com/products/brake-fluids/

[Tuned forks]

Well it made the trip "interesting".  11-1 compression, 427 ci and a Muncie M-21 was surprisingly able to slow me down for the curves.

Perhaps now it has a higher boiling point and that's a good thing.  The product I bought 20 years ago was lower than the traditional fluid.  Hopefully there is no longer air in the fluid too.

Joe

[Pat Conlon]

Pat, even though rotors are often soft cast iron, I've found them to be rather hard.  What do you use to scuff the rotors effectively?

Joe

Sorry Joe, I missed your post^^

Zip zip with my cordless drill

https://www.summitracing.com/parts/brh-rmfh120z25?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-brush-research&gclid=CjwKCAjwsfreBRB9EiwAikSUHQyApVIwbZSdTKtlG-emJkzh4OrP13OYKsSbwXVu6aS45vgVyd1ZbBoCnawQAvD_BwE

I use the poor man's lathe.
Lift the front end up, remove calipers (leave lines attached) tie them up out of the way, hold the drill at a slight angle perpendicular to the rotor face, then spin the tire, zip zip....then, spin the tire the opposite way, zip zip..(you get a nice even cross hatched finish) so that does the outside faces.

Now to do the inside faces: Remove the rim, flip the rotors around so inside face is out, reinstall the rim, spin the tire both ways,  zip zip.

Don't forget to go thru the important process of bedding in the pads to get a nice even transfer layer deposited on the now clean rotors.

Cheers

[Tuned forks]

That's so cool and ideas like that are the reason we are on this forum.  Thanks for sharing Pat.

Joe

[Ed Ramberger]

I thought I had a slipping clutch for a year instead of a bad second and third gear so i ran a double clutch spring with a stock master cylinder on my 84 FJ1100 .i pulled the second spring out but the clutch now didn't fully release. I rebuilt the master cylinder because it started to leak and then found out how bad my clutch handle was.I'm glad i don't need the double spring.            I know everything I've ever seen has said you absolutely can not use dot 5 in a (dot 3,dot 4,dot 5.1)  system but after reading a a post from an engineer who restores and maintains his own vintage triumph cars i am tempted to try it with my clutch. does anyone have experience with this?

I converted my bike over to DOT 5 (brakes and clutch) because I have a Harley (in same picture) where the master cyl leaked.  Luckily it was DOT5 because it had spend the day dripping on the tank.

I was very leery and when working at Harley, asked a brake engineer at work.  All the rubber components, seals, hoses, etc etc are the same except for the cap (identifies the fluid) in the HD systems - he explained the components are the same, the concern is mixing without completely flushing.  Also, DOT 5 is not to be used in ABS due to its nature to hold bubbles and ABS manufacturers won't green light it.

I just flushed everything well. Several years later (like eight) I needed a MC rebuild but hell, it's an 89.  

I have not had any problems, and I am confident that my paint which is practically mint will not be damaged by brake fluid.