Silicone brake fluid

**Mick_Marsh** · 23rd July 2012, 08:30 PM

I'm thinking of using some.
I know Ron (101Ron) reckons it's good stuff but are there other people who use it or know about it?
I read this today:
Since DOT 4 fluids were developed, it was recognized that borate ester based fluids offered the potential for boiling points beyond the 446F requirement, thus came the Super DOT 4 fluids - some covered by the DOT 5.1 designation - which exhibit a minimum dry boiling point of 500F (same as silicone, but different chemistry).

You can go ahead and mix or flush (replace) any DOT 3, DOT 4, or DOT 5.1 brake fluids, no problem. So there are no special bleeding procedures and you don't need to run anything in the lines. The only one to watch out for is DOT 5 (silicone brake fluid).

DOT 5 does not damage paint like other brake fluids do, but is not recommended by AP Lockheed for use in their systems due to higher wear than with other type fluids.

Brake system contamination:

The single most common brake system failure caused by a contaminant is swelling of the rubber components (piston seals etc.) due to the introduction of petroleum based products (motor oil, power steering fluid, mineral oil, etc.) A small amount is enough to do major damage. Flushing with mineral spirits is enough to cause a complete system failure in a short time. I suspect this is what has happened when some owners change to DOT 5 (and then assumed that silicone caused the problem). Flushing with alcohol also causes problems. Brake systems should be flushed only with DOT 3 or 4.

If silicone is introduced into an older brake system, the silicone will latch unto the sludge generated by gradual component deterioration and create a gelatin like goop which will attract more crud and eventually plug up metering orifices or cause pistons to stick. If you have already changed to DOT 5, don't compound your initial mistake and change back. Silicone is very tenacious stuff and you will never get it all out of your system. Just change the fluid regularly. For those who race using silicone fluid, I recommend that you crack the bleed screws before each racing session to insure that there is no water in the calipers.

It is not recommend use of DOT 5 silicone brake fluid on British motorcycles equipped with any AP Lockeed disc brake components.

Let the discussion begin.
(It would be good to read about things other than Hiclones, HHO generators and Energy Polarisers (the last of which did not increase my fuel consumption).)

**LandyAndy** · 23rd July 2012, 08:45 PM

Hi Mick
Steer clear unless you are building an EX ARMY racecar

As stated in your quote,it CANNOT be mixed with other brakefluids.
If you do develop a decent leak away from home it may be hard to get silicone fluid,normal brakefluid is available everywhere.
Its use really only has a home on the racetrack or supercars.
Andrew

**blackbuttdisco** · 24th July 2012, 07:09 AM

How often do you need brake fluid on the side of the road? I have only needed it once in 50 years and I have been using silicone for the past 20years, in 4 Triumph 2500's, 3 Triumph TR7's, 2 Volvos, and 2 Landrovers and 2 1951 Austins. I won't use anything else. Its up to you though.

**101 Ron** · 24th July 2012, 06:18 PM

Vintage & Classic Car Silicone Dot 5 Brake Fluid
Brake Fluid
D.O.T. 5 Brake Fluid

I like this one.
Some one has done the home work and is not full of BS.
It refects what I have found using the slicone fluid in real life

Selecting Brake Fluid

**mick88** · 24th July 2012, 06:44 PM

Hey Mick,
make sure you don't get it confused with DOT 5.1 as it's DOT 5.
I use it in my series 3 clutch and brakes and also it is in a series 2A that I have. I am the second owner of that vehicle (2A) and it has had silicone in it since just after the guy purchased it brand new in 1971.
I also use it in my Tojo Hi Lux and no problems there.
The best place I have found to buy it is at a Harley Shop, as they use it in a vast range of their motorcycles.
Another big user is the American Military, as it is suitable for any climate in the world..according to them.

Cheers, Mick.

**101 Ron** · 24th July 2012, 06:49 PM

I just love reading some of the BS on the internet.
Softer pedal ?..........hasnt happened to me.
The two different fluids mixed together will cause problems.........hasnt happened to me.
hoses and seals giving out with silicone fluid ....no on that one too and thats after more than six years of use.......in fact the brake components are working better and lasting longer.
Hard to bleed brakes ?.........i havent had a problem.
I have used the stuff in many different vehicles without problem.
I never had brake fade with a silicone fluid..........but yes with normal brake fluid.
Silicone fluid expensive and hard to find.......yes.
I like one comment above some where, that you cannot buy it everywhere if you need it on a trip.
I carrry a small amount of brake fluid in all my vehicles, because if you should need fluid of any type it nevers happens to be near a servo.(remember you can mix the two different types of fluid if you need to.)
I was working on a forklift to day.....a crown electric reach truck and it is 22 years old and I know the history of it too.
Crown recommends silicone brake fluid, yet few forklift service men ever carry the stuff, so normal fluid goes in.
This fork has been running a mixture of fluids for years and it is fitted with twin alloy master cylinders and a mixture of alloy and cast iron wheel cylinders.......no problems
The slicone fluid is recomended not for heat resistance ( a forklift doesnt go fast enough), but everytime the operator hops on or off the unit, or stops the machine the master cylinders are in use........alot more than a car or truck.
brake parts last longer with silicone fluid.
the cheap chinese mini bike you buy to day have hydraulic front and rear disc brakes.
the handle bar mounted master cylinder , even though they are sealed from the atmostphere will in time , first bubble the the paint around the cylinder reservoir and then leak and corrode the master cylinder and you find your up for another master cylinder..............guess what fixes the problem...silicone fluid.
Why do i go on about Silicone fluid , simpley cause real world use of the stuff and BS about it seem to be worlds apart.

**mick88** · 24th July 2012, 06:49 PM

Clutch fluid leak - master cylinder?

Another thread about silicone brakle fluid!

Cheers, Mick.

**mick88** · 24th July 2012, 06:56 PM

Dot 5

Another thread about silicone brake fluid!

Cheers, Mick.[/QUOTE]

**101 Ron** · 24th July 2012, 07:21 PM

This is the brand I use.
RUSSELL DOT 5 SILICONE BRAKE FLUID from Parts Canada Snow

The local motor parts place gets it in on special order for me.

**Mick_Marsh** · 24th July 2012, 07:26 PM

Thanks for the responses people. 'Tis all good stuff.
I know you're a converted user of this stuff Ron. Thanks for the concise point form. I didn't know you could mix the fluids.
Keep the facts coming. (oh, and best places to buy)

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