Silicone Brake Fluid.... Should I use it ?

[72MARIO]

I just bought my new master Cyl for manual brakes. I am going to spray it torch red just like the fire wall. I dont want the brake fluid to peal the paint off my firewall and MC. So I have been told about Silicone. Is it oky to use in these systems ??


I have all new brake Stainless 20 straight lengths coming this Friday. The entire system is dry and brand new.

Let me know you thoughts.

Mario

[zeeklu]

As long as the wheel cylinders and calipers are clean you won't have any problems. I've used it in my 67 k10 for 5 or 6 years with no side effects at all.
Just pour it in slow ,don't shake the bottle, pump the pedal slowly when bleeding and you will be good to go. I usually open all the bleeders and fill the system and let it gravity bleed before I start the regular bleeding routine. Chris

[Longhorn Man]

I lost the link, maybe some one here still has it, but silicone isn't a good idea for a driver.
Acording to the articles I've read on it, it is actually a BAD idea for a driver...better suited for a race car or a trailer queen.

[zeeklu]

I've had it in my driver for 5 or 6 years and 50K miles but that doesn't mean my results are the norm. Chris

[Gee_Emm]

Silcone fluid is perfectly fine to use. The only problem is that you would have to get ALL of your old fluid out, and then flush the system before changing over. If you are using all new parts then you are good to go. Silicone has great advantages like not absorbing water from the air, not eating paint and better heat capabilties.

[zeeklu]

But supposedly it does hold air bubbles longer than regular brake fluid but I didn't have any problems. The nice thing is how clean the system stays. You can take the lid off the mastercylinder and still see the ports in the bottom through the silicone fluid like you were looking through water. Chris

[ratrod67]

I run the silicone fluid in all my older cars. Haven't had any problems yet. I've heard of a lot of people not getting as firm of a pedal with the silicone but I think it's because they haven't gotten the system bled well enough.

[RON WOODGEARD]

I've ran Silicone for over twenty years... It's been in this truck for 18....

Just be sure as you typed "ALL" of the other is out of the System, they are NOT compatible whatsoever...

It comes FACTORY in many vehicles..It is not bad as long as the changeover is done correctly.

Replace or clean with alchohol every rubber part in the system, and as I already typed, ALL of the old stuff HAS to be OUT...

[Longhorn Man]

One thing i remember is that since the sillicone stuff doesn't absorb water, the water that gets in there from normal humidity/condencation doesn't mix and sinks to the lowest point of the system and rusts the lines from the inside out.

[4x4Poet]

Consider synthetic DOT 3 or 4 fluid. I was in Checker, of all parts places, and they had Valvoline synthetic brake fluid for sale. A little more costly than petro brake fluid, but the synthetic is compatible with petro fluid, so I can use it without having to start with a clean, dry system and can use any DOT 3 or 4 fluid with it, say if I'm unable to find synthetic. The synthetic should not break down as easily as petro fluid. For our street driven trucks, I think these advantages outweigh any of silicone fluid's advantages, namely the ability to handle high heat IIRC.

Originally Posted by Longhorn Man

One thing i remember is that since the sillicone stuff doesn't absorb water, the water that gets in there from normal humidity/condencation doesn't mix and sinks to the lowest point of the system and rusts the lines from the inside out.

Interesting, LM. I never thought of that possibility. Not that it matters since I'll probably never use silicone brake fluid.

[RON WOODGEARD]

It'll work..

[zeeklu]

If the system is full to the top and the rubber diaphram in the lid is against the top of the fluid where would the condensation come from? Chris

[BurnoutNova]

dot 5 costs about 4x what normal dot3 costs, but your ENTIRE system ptobobly only holds 1qt at the most.


i'd go with it if all my stuff were new.

[mocwon]

Stainless lines like Mario is getting should not rust.

[72MARIO]

Oky,

Sounds Good.

I checked into pricing it's a bit more but if I have to get the inner fender resprayed the paint is going to be more than the diffirence in cost between regular and silicone brake fluid. I am going to pick some up when I get the lines.

Thanks for the help.

Mario

[Longhorn Man]

zeeklu, water will get in there. no matter what you do, it will get in.
When you depress the pedal, fluid is forced through the lines...somethign has to take the space where the fluid once was...in the resivour. Air will move in. Air with humidity.
Plus, if you have it that full, then you have it overfilled anyways.

[724wdcopper]

isnt that where the rubber bladders in the MC lid come in? they fill with the incoming air, preventing it from mixing with the fluid? of course, like you, i believe some air WILL eventually enter the system from one source or another. but it will with regular brake fluid, too, so i dont see a whole lot of difference. how often does everyone check their brake fluid level? i for one have probably neglected it more than i've monitored it. whichever way you go, proper maintenence would be the key.

[tom hand]

The only problem you will have with it if changed over properly, is that is doesn't work well at high altitudes...somthing to do with the boiling point. If you go to really high altitude you will have a spongy pedal and there is nothing you can do about it...at sea level you will have no problems and it will save the paint

[BubbaGreen]

Hey folks, this is an interesting subject....I replaced the DOT3 fluid in my '86 mustang when it was new...then I read the manual where it stated "DONT USE SILICONE" brake fluid. Well, lets just say, its been in there for almost 20yrs now. I have had absolutely no issues with the brakes, its not a daily driver, but I do have 80K on the car now and I have owned it since new.
Thing is, I am almost done doing a frame off resto on my 71 truck, and purchased a new master cylinder from master power brakes (the power assist version) and all new components, ie, calipers, rear cylinders, prop-valve, and all sst lines. But have been thinking the DOT4 Valvoline brake fluid over silicone. MasterpowerBrakes states they will instantly void the lifetime warranty if silicone fluid is used and I am not really sure why. Original DOT3 fluid just bites the bullet, it ruins paint with no advantages. DOT4 seems to just cost more and still it eats paint...DOT5 seems like the cats meow, but it cost more and for some reason, manufactures say to avoid it....uhm....

[mr402]

I haven't heard too much about the synthetic brake fluid. Is it any better as far as not eating paint? 4X4 what was your experience with it?

I went to silicone fluid in my 62 Impala a good 15+ years ago. I have had no brake issues since that time. I know that with any other fluid I would have had to rebuild the wheel cylinders at least once or twice in the same time period. Main reason I did was because it's a garage queen. I rebuilt the wheel cylinders when I first got it and 3 years later they needed them again. At that point I redid everything and tried the silicone fluid and haven't looked back since.

[Canadian72GMC]

Well, here goes. Silicone brake fluid and regular DOT 3 or 4 will not mix. They will stay separated. I would not waste time cleaning out the system to change to one or the other though. They will not harm one another. DOT 3 and 4 are hydroscopic. They absorb water. This feature is essential in a brake system. Brake fluid will absorb moisture through the bladder in the m/c, through brake hoses, and simply from removing the lid, at the rate of about 1% per year on average. It can absorb up to about 3% of it's volume.2% moisture will reduce the boiling point of brake fluid almost by half. Not normally a problem unless you do severe braking(mountain driving etc). Boiling brake fluid is just that-liquid to gas, gas is compressible = no brakes. Brake fluid for that reason alone should be changed every 2 years. Silicone brake fluid (DOT 5), as previously mentioned, does not absorb water. Water will migrate to lower areas in the brake system, typically wheel cylinders and calipers, causing rust and brake problems.It does however have a higher boiling point. DO NOT USE SILICONE BRAKE FLUID IN BRAKE SYSTEMS WITH ABS. Yes, I was yelling. There are very finely machined electronic valves and actuators in all ABS systems(expensive) that will not tolerate ANY moisture or rust.

[neonlarry]

DOT 3 & 4 absorb water DOT 5 does not, like Andy said that water (and there will be water eventually) sits next to your metal parts and rusts. The real advantage of DOT 5 is increased boiling point, this is a real advantage in race cars. But race cars usually have their fliud changed after every race so water buildup is not a problem. All I can say about leaving the same brake fluid in your car for 20yrs is how long do you leave your oil in? Brake fluid should be changed about as often as antifreeze, every year.

[RON WOODGEARD]

Originally Posted by neonlarry

DOT 3 & 4 absorb water DOT 5 does not, like Andy said that water (and there will be water eventually) sits next to your metal parts and rusts. The real advantage of DOT 5 is increased boiling point, this is a real advantage in race cars. But race cars usually have their fliud changed after every race so water buildup is not a problem. All I can say about leaving the same brake fluid in your car for 20yrs is how long do you leave your oil in? Brake fluid should be changed about as often as antifreeze, every year.

Neon, You're absolutely right about changing the Fluid, But it's like the tranny fluid, it's something that unfortunately gets skipped over as a Maintenance issue....

I've changed the brake fluid in my truck, every other year in the last 18 years.... Tranny Fluid every year. Along with the Rear end fluid, and Anti-Freeze...

[4x4Poet]

Originally Posted by 72MARIO

Oky, So am I stil good to go with the silicone ? Just change it every 2 years ?

Looks like a big yes all around, 72MARIO.

Originally Posted by tom hand

The only problem you will have with it if changed over properly, is that is doesn't work well at high altitudes...somthing to do with the boiling point. If you go to really high altitude you will have a spongy pedal and there is nothing you can do about it...at sea level you will have no problems and it will save the paint

I've heard of the spongy pedal problem. Never knew why until now.

Originally Posted by mr402

I haven't heard too much about the synthetic brake fluid. Is it any better as far as not eating paint? 4X4 what was your experience with it?...

Synthetic brake fluid definitely eats paint. No need to ask me how I know. I found it last Fall just as I was overhauling my TravelAll's brake system. New master; SS braided hoses; PDB shoes, springs, and wheel cyls; a few new SS hard lines mixed in with the old. The brakes work great, but I haven't noticed anything superior about it. I just figured that, like synthetic oil, it would not break down as easy and maybe not absorb as much moisture as petro brake fluid.

Originally Posted by neonlarry

...Brake fluid should be changed about as often as antifreeze, every year.

Great point, neonlarry. I think I have a good flush tip. I don't have a mityvac, so I use one of those battery bulb suckers (tech name) to suck out most of the fluid from each reservoir without letting air hit the bottoms so as to keep air out of the system. (I use a coffee can to catch the fluid with rags under the master.) Then, I fill each reservoir with new and, while keeping the reservoirs full, bleed the brakes till I see new fluid come out. This way I don't flush all the moisture ridden reservoir fluid thru the lines and past the calipers/wheel cyls. And fresh fluid hits the bleeders sooner.

[72MARIO]

Oky, So am I stil good to go with the silicone ? Just change it every 2 years ?