GRX

I've heard good and bad about silicone brake fluid (DOT5). Does anyone use it in their brakes or clutch systems?

Half Fast

Do not use it! Only use DOT 3/4 or 5.1

JCAIRE2

:iagree: Any water that enters the system will find the lowest point, ie. in the calipers, and you will have braking/ corrosion problems.

Mrcorvette91

Also, the DOT 5 will NOT mix with the other brake fluids. I use the DOT5 in my Boss Hoss, and found out the hard way that it doesn't mix. Just creates a sludge in the braking system. The Boss has Wilwood braking systems, and when mixed, means you have to buy new master cylinder, lines, and also new calipers. Believe me, (who has made a $700.00 mistake on the rear caliper), don't mix them. The DOT5 fluid works well, is resistant to high temps more than the others, does not harm painted surfaces at all. BUT, the down side to the DOT5 is it results in more frequent brake bleeding (for some reason), and also costs almost $8.00 for a small bottle. The Boss is the only thing I would use it in, never my Vette. I hope this helps answer your question. :thumbs:

C10 JDR

But since Dot 5 is not hygroscopic, (i.e. doesn't absorb water from the atmosphere) how on earth is water going to get in there - short of pouring it in. It is non-corrosive, as stated above, doesn't need changing - it is superior to the other stuff - apart from in ABS systems where the valve body action can foam it up. I used it on my C3 Corvette, and on my "74 Jaguar with absolutely NO problems for years. Not on MY C4 or Range Rover though - they have ABS. (Although it doesn't work on the C4 - of course)

If you do change to DOT 5, again as stated earlier, then I would recommend stripping the calipers for new seals, and flushing the lines out with meths.

I say yes to DOT 5 - it gets my vote.

Failing that , use 5.1 synthetic, if you don't want to change the seals etc.

:thumbs:

c4cruiser

I recall reading somewhere (maybe the Autocrossing and Road Racing Forum) that DOT5 fluid and ABS do not mix. The DOT5 fluid will cause cavitation in the ABS pump resulting in bubbles in the fluid and introducing then in the brake lines.

C10 JDR

I think I just said that. Thanks for your support. Dot 5 is the dogs.

Anybody actually used it and doesn't like it?


[Modified by britvette, 2:10 AM 8/17/2003]

JCAIRE2

http://www.rpmnet.com/techart/fluid.shtml
Diffusion is another way in that water/moisture may enter the system.

Diffusion occurs when over time moisture enters through rubber brake hoses. The use of hoses made from EPDM materials (Ethlene-Propylene-Diene-Materials) will reduce the amount of diffusion OR use steel braided brake hose with a non-rubber sleeve (usually Teflon) to greatly reduce the diffusion process.

http://www.shotimes.com/SHO3brakefluid.html Silicone brake fluid (DOT 5) should be avoided because it is not compatible with regular brake fluid, it is hard to pour without introducing bubbles and thus results in soft pedal feel, and moisture still gets into your system and will pool in low areas like your calipers and encourage rapid corrosion.


That's two examples I pulled from a google search. If it was in a completely waterproof system, then it would be a choice. Why would they still give a wet and dry boiling point if it wouldn't interact with water?:rolleyes: Even most manufacturers of DOT5 fluid warn against using in a street vehicle.

C10 JDR

As DOT5 is not hygroscopic, water will not diffuse in there, through rubber hoses or any other way, so I still maintain short of pouring it in.....

OK, but I still say I have used it for years in two vehicles, both fairly heavy and both fairly fast, and have had no problems, and no spongy pedal.

If I were to change the fluid every year or less, possibly non-silicone is the answer. But if, like most people (not necessarily enthusiasts) the stuff is just topped up once in a blue moon, I favour silicone.

Has anyone reading this personally had bad experiences with DOT5?

Maybe I 'm just lucky! :blueangel:


[Modified by britvette, 8:44 PM 8/17/2003]

C10 JDR

No response - I rest my case.

( If there was an emoticon for smug and self-satisfied, I would insert it here) :hat

JCAIRE2

Or you could chalk it up to no one using it:p:

Not trying to flame, but when there are better options available why would anyone use a fluid in a C4 that's incompatible with ABS and has a chance of ruining a the system?

speedracer1996

If it's not broke, then why try to fix it :) Oh the whole deal with the boiling point is simply molecular interactions. Even if the two liquids are not miscible, the molecular interactions (london dispersion forces) will still have an effect on the specific heat of the solution (even if that effect is noticeable only with very precise equipment). All chemical data sheets have specific requirements as far what will be listed. It's just standard operating redundancy. BTW, I am not familiar with interactions between silicone brake fluid and water, so this is simply a general answer. Hope it helps :D

Cratzy

I've used it now for almost two years in my 91' Vette, with ABS. No problems at all. I haven't changed it yet. I use braided brake lines. Of course I pumped out all the old DOT 4 before I filled her up with the DOT 5. The brakes works fine and I can't see any corrosion.
:cool:

gene284

I've used silicone brake fluid for years in cars without ABS. They showed no signs of moisture problems, unlike regular brake fluid. They literally looked good as new.

I found nothing but sludge in purchasing cars with older standard brake fluid.

Don't most of the rubber enhancing solutions used in detailing cars use silicone?


I don't know about ABS problems, but in normal driving use, I would always go with slicone brake fluid.

JCAIRE2

Ok, now you can insert the smug and self-satisfied smiley :) I really didn't think anyone was using this in the c4. I still would rather use DOT4 or 5.1 in mine. :cheers:

C10 JDR

Thanks for that!

This topic seems to be one of those where it is fashionable to be "against" (DOT 5 that is), and yet everybody I have spoken to who actually uses the stuff is "for". This is why I stirred it up a bit and risked a few flames, because I think we should reconsider the accepted "truth" here on the forum and maybe we will learn something.

If I could be bothered to strip my calipers I would use it, but I can't, so its 5.1 for me!

:cheers:

GRX

:lurk: