The Stovebolt Site Forums The Shop Area Driveline Synthetic vs Regular brake fluid

I'm installing new stainless brake lines and new cylinders. I'm curious what others are using synthetic or regular brake fluid? (I searched the forums but didn't find any info). I've read that synthetic can sometimes leak past the brake cylinder rubber pistons & that it is harder to bleed. With stainless lines and new cylinders, is the synthetic property of not absorbing water no longer an advantage? Have folks had any issues? Thanks! (ps. I have a 46, so the stop light switch is mechanical).

When you say "synthetic" brake fluid I believe you are referring to "silicone" brake fluid. There has been alot of information about this topic on this site, so I would try your search using "silicone".

I think that most people use regular brake fluid (DOT 3) due to their familiarity with the product and it is true there are compatibility issues with rubber cups in the master and brake cylinders. Still, there are some who advocate silicone (DOT 5).

Kent

I've been using the Dot 5 in my turck for the past 7 or 8 years. Haven't had a problem with it yet. I like it. Others will disagree.

There is a lot of info on the silicone brake fluid subject.

Have fun.
George

I built (2) street rods and used silicone brake fluid on both.

Like you I ran all stainless lines, and I used a new master cylinder and brake cylinders. Since everything was new there was no compatability problems related to old brake fluid in the system.

One of the cars is now 12 years old, the other is 8 years old.

I have had no problems whatsoever with either of the vehicles.

Thanks all - that was a dumb mental mis-fire of mine. Don't know why I was searching on synthetic. Thanks!

I have used silicone fluid in my mga for the last 28 years with no problems. the one issue is it has a slightly spongy pedal. this may not be relevant but in the past is was not advised too use in corvette brake systems. it will seep over time, maybe because i only use the car in the summer and it sits most of the time.

If you use silicone, you must make 100% sure any rubber componenets in the system are compatible. Not all manufacturers use silicone compatible rubber, EIS was the only company I know for sure did, and they are no longer in business. Since silicone fluid is not factory fill on any current production car, exept maybe for some European cars, most rubber parts only have to work with DOT3, 4, and 5.1. I tried silicone, because of the non-hygroscopic qualities and that it won't eat paint, but found out that it was not compatible with the brake parts I used. 2 leaky wheel cylinders and leaking master cylinder (all new when the brakes were installed) convinced me to go back to DOT3. I did contact the manufacturer (Wagner), and they informed me that they only manufactuer their parts for the OEM fluid fill.
I won't say not to use it, but please make sure that there won't be a problem with using with whatever brand parts you use. Loosing your brakes is not worth any benifits you may gain.

it doesn't absorb water, thusly won't eat up cylinders. we HAD to use it in Chignik AK, the atmosphere was such, regular brake fluid allowed the cylinders to completely die within 1 or 2 years, after we swithced to silicone that all went away. You have to make sure you use NEW rubber parts that have never been used with dot 3 that are compatible with silicone, and flush the system with alcohol is what we used. I'm completely sold on it myself, after seeing the difference.