Moparts

silicone brake fluid

Posted By: Barnstorm

silicone brake fluid - 06/09/09 06:56 PM

Have been using silicone brake fluid in my 4 corner Wilwoods for 10 years with no apparent issues. Called Wilwood to order some seals and was advised not to use it. Back in the day it was thought to eliminate moisture issues and rust. Any experiences?

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Posted By: sixpackgut

Re: silicone brake fluid - 06/09/09 07:01 PM

me and Quicktree got that same lecture at the PRI show. i cant remember as to why its no good to use
Posted By: Hemi_Joel

Re: silicone brake fluid - 06/09/09 07:31 PM

I have been using it forever with no issues. My 442 has had it since 1982 and never had a problem.

I've had in in Wilwoods for at least 6 years with no problems.


But you better quit using it, just ask Chicken Little.
Posted By: Quicktree

Re: silicone brake fluid - 06/09/09 07:56 PM

Quote:

me and Quicktree got that same lecture at the PRI show. i cant remember as to why its no good to use




they said it draws moisture into the system.
Posted By: CokeBottleKid

Re: silicone brake fluid - 06/09/09 08:00 PM

Ya I've heard basically the same stuff. My friends been using it since the 80s in his stock AAR with no problems, it's mainly worth it to prevent paint damage with leaks, it's saved his paint many times.
Posted By: Lee446

Re: silicone brake fluid - 06/10/09 01:49 AM

Regular brake fluid is hygroscopic, draws moisture. Silicone Does Not. I have run silicone in my cars for over 20 years with zero problems. I even run it in my surge brake equipped trailer that sits in a field in the weather year round, the silicone fluid is as clear and clean as the day it went in, and that was ten years ago. As long as you are not a road racer, it is a good choice.
Posted By: Michael

Re: silicone brake fluid - 06/10/09 03:04 AM

It's been in my street driven, drum braked car for 10 years-----no problems.
Posted By: Dartman75

Re: silicone brake fluid - 06/10/09 04:57 AM

The only problems silicone caused for me was to cause hard pedal, which wasn't "spongy enough" for the vac booster to not assist at all. With the squishier DOT fluids the booster would work better. It's possible that people have similar issue and then complain to Willwood and they just want to avoid having those common complaints? I use DOT5 and hydroboost and it works just fine even with nearly no pedal travel for my brake current system.
Posted By: John_T_Brown

Re: silicone brake fluid - 06/10/09 12:51 PM

I did use Dot 5 in the ‘80’s but went back to using racing brake fluid (Dot 4) because of the following issues.

1. Silicone brake fluid entrains air bubbles easily when pouring and or maintaining the system and produces spongy feeling if not properly handled.

2. It doesn't absorb water, so any water that gets into the system accumulates in the lowest point stays there and causes rust mainly at the wheel cylinders and/or calipers which may cause seal failure at that point.

3. Some silicone fluids have additives that can vaporize at moderate temperatures, increasing the spongy feel in some instances.

4. Silicone fluid is incompatible with systems that have held glycol-based fluids for any length of time, require total rebuild of the brake system. Flushing and seal replacement can be done but extreme caution must be used when performing this task. There are other opinions on this which state that the modern silicone formulations are compatible with only a flushing and a complete reseal is not necessary (The actual DOT specification requires chemical compatibility so the two fluids won't cause reactions if used in the same system, but they certainly won't mix, either…You decide, it’s your car and possibly your life at stake here).

In closing, it might be fine for some people to use this fluid but do you really want to risk it all just to use a fluid that won’t damage your paint?

Most serious racers use this fluid
Castrol SRF

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Posted By: Hemi_Joel

Re: silicone brake fluid - 06/10/09 02:35 PM

Quote:

...In closing, it might be fine for some people to use this fluid but do you really want to risk it all just to use a fluid that won’t damage your paint?...






The point is, that there is LESS risk with DOT 5. With DOT 3, you are guaranteed to have a moisure related failure of your brakes if you keep it in there long enuff. It is just a matter of time. DOT 3 is a moisture magnet, it sucks in moisture and corrodes the cylinders.

For me, using DOT 5 has nothing to do with paint. I have had it in my 442 for 27 years. Most of my older cars now have silicone fluid. As the DOT 3 equiped systems fail, (and they all fail) I re-do them with DOT 5. The only exception is my 49 Plymouth, because I rebuilt the brakes at the site where I bought the car so I could drive it home, and the local parts store did not have enuff DOT 5. That was in '93 and I have replaced one or 2 wheel cylinders due to corrision at least twice, taken them apart and cleaned and re-assembled them and cleaned fluid off the shoes at least a couple more times. Every spring when I get the car out of storage, I have to allow time to mess with the brakes. Meanwhile, none of my silicone fluid equiped cars have had any problems.
I don't care what Wilwood or anybody else thinks, 27 years of experience proves that dot 5 is better, safer, and more reliable, at least in my circumstances.
Posted By: CokeBottleKid

Re: silicone brake fluid - 06/10/09 04:35 PM

Quote:

I did use Dot 5 in the ‘80’s but went back to using racing brake fluid (Dot 4) because of the following issues.

1. Silicone brake fluid entrains air bubbles easily when pouring and or maintaining the system and produces spongy feeling if not properly handled.

2. It doesn't absorb water, so any water that gets into the system accumulates in the lowest point stays there and causes rust mainly at the wheel cylinders and/or calipers which may cause seal failure at that point.

3. Some silicone fluids have additives that can vaporize at moderate temperatures, increasing the spongy feel in some instances.

4. Silicone fluid is incompatible with systems that have held glycol-based fluids for any length of time, require total rebuild of the brake system. Flushing and seal replacement can be done but extreme caution must be used when performing this task. There are other opinions on this which state that the modern silicone formulations are compatible with only a flushing and a complete reseal is not necessary (The actual DOT specification requires chemical compatibility so the two fluids won't cause reactions if used in the same system, but they certainly won't mix, either…You decide, it’s your car and possibly your life at stake here).

In closing, it might be fine for some people to use this fluid but do you really want to risk it all just to use a fluid that won’t damage your paint?

Most serious racers use this fluid
Castrol SRF




Well considering the O.P HAS been using silicone you don't have to worry about him flushing it. I say he stays with it
Posted By: Hemi_Joel

Re: silicone brake fluid - 11/11/17 10:43 PM

Guess who is now selling the evil DOT 5 fluid? xmaseek

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Posted By: Racer68

Re: silicone brake fluid - 11/11/17 11:19 PM

I may be a bad example because I don't drive my car much but I use Dot 5 fluid. The only thing I noticed was that it was harder to bleed the brakes and the pedal is a little spongey.
Not long ago I was at a body shop that does tons of Mopars. He had a 68 SS Dart in the shop. He was repainting the firewall and inner fenders because they weren't using Dot 5 fluid and wheel stands had sprayed fluid all over the engine compartment. They had already pulled the motor for a freshen up so it was a good time to address the brake fluid damage. If you're worried about moisture accumulating in the calipers you could always flush some new Dot 5 through it to remove any moisture without having to actually bleed again. By the way I was told that the master cyl in the Dart was overfilled.
Posted By: Jeremiah

Re: silicone brake fluid - 11/12/17 03:45 AM

Exciting, I love a good DOT5 brake fluid thread.

We have DOT5 in everything from four wheel drums to four wheel discs. If my new (to me) 5 yard dump truck didn't have air brakes I'd put it in that too.

After 5 years as an all weather driver in Oregon everything inspects okay and a quick flush produced nice looking fluid. This particular car has original wheel cylinders that I honed on the car and put kits in too.

The only down side of DOT5 is aeration. If you get tiny bubbles in the system by pumping to fast, and air leak, etc. they can be time consuming to get out of the system. Switching from the various parts house brands to Cartel DOT5 Brake Fluid solved my aeration issues when bleeding new or freshly refurbished systems.

http://www.cartelproducts.com/performancebrakefluids/siliconebrakefluiddot5.html
Posted By: dvw

Re: silicone brake fluid - 11/12/17 04:02 AM

My Willwoods were reused from my old car. They were originally purchased in 1992. Been on the current car for 5 years. Always run with DOT 5. I pulled them a part a few years ago to look. Everything was fine. I did replace the seals since they were apart but at the time they still were functioning perfectly.
Doug
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