Getting rid of DOT5 silcone Brake Fluid

[icemanrd19]

Spoke to willwood as well and they said the same thing today. Now I believe if you just mix them and leave the mix it will gunk but I don’t believe if you bleed a gallon of dot 3 fluid and do it again after driving a week it will gunk. I did find a solution. Let my buddy go first and report back before I do it lol

I was told by Wilwood that all seals had to be replaced in the calipers and master cylinder, along with a new proportioning valve after flushing the system.

Unless you're having pedal issues, you may want to leave it alone. Throwing some ducting to the brakes may help curb it.

[GoodysGotaCuda]

Spoke to willwood as well and they said the same thing today. Now I believe if you just mix them and leave the mix it will gunk but I don’t believe if you bleed a gallon of dot 3 fluid and do it again after driving a week it will gunk. I did find a solution. Let my buddy go first and report back before I do it lol

Silicone [dot 5] repels just about everything, this is no different. They don't mix and it's not really a conspiracy theory, Wilwood [or anyone here] has nothing to gain by leading you astray...

[67King]

Silicone [dot 5] repels just about everything, this is no different. They don't mix and it's not really a conspiracy theory, Wilwood [or anyone here] has nothing to gain by leading you astray...

+1. From memory, silicone polymers are (-Si-O-), so they are inorganic, whereas all of the other stuff (DOT 3, 4, 4+, and 5.1) are all organic. So they don't mix. Depending on what the R's are on the silicone chain, they might have some stuff there that would react, but as the base chain is inorganic, it is a bit like mixing oil and water.

[icemanrd19]

Figured I would update this.

I started by sucking most of the reservoir brake fluid out. I then went to the farthest caliper on the right rear and ran 3/4 of a 32oz bottle thru the system vacuum sucking the caliper while someone else slightly pushed on the brake pedal. Fluid started out pretty green and cleared up some. I then did this to the lr, rf, and then the lf running half a 32oz bottle in each caliper doing the same method. I then went back and repeated this process. Again. This time I noticed the fluid was pretty clear. After doing those 4 calipers again I did this again but with only 2 brake pedal pushes and the fluid looked clear as can be in each caliper. All in all I used 4 bottles of 32oz brake fluid and after each caliper I poured the old fluid in a cup to compared. Went on a test drive and the brakes feel great. I will drive it for about a week or two and run another 32oz bottle in the system. Cost was about $30 for the brake fluid from Walmart and $30 brake flush machine from harbor freight.

[XLexusTech]

Figured I would update this.

I started by sucking most of the reservoir brake fluid out. I then went to the farthest caliper on the right rear and ran 3/4 of a 32oz bottle thru the system vacuum sucking the caliper while someone else slightly pushed on the brake pedal. Fluid started out pretty green and cleared up some. I then did this to the lr, rf, and then the lf running half a 32oz bottle in each caliper doing the same method. I then went back and repeated this process. Again. This time I noticed the fluid was pretty clear. After doing those 4 calipers again I did this again but with only 2 brake pedal pushes and the fluid looked clear as can be in each caliper. All in all I used 4 bottles of 32oz brake fluid and after each caliper I poured the old fluid in a cup to compared. Went on a test drive and the brakes feel great. I will drive it for about a week or two and run another 32oz bottle in the system. Cost was about $30 for the brake fluid from Walmart and $30 brake flush machine from harbor freight.

Awesome.. can you share a link to the fluid you used.. ?

[icemanrd19]

Just some reg Walmart 32oz Preston braken fluid. Brake fluid is still great and I’ve ran it hard at piles peak optima event. No issues.

[TheBandit]

Whatever you do, do not flush the system with a petroleum distillate like mineral spirits, because they can interact with rubber components and cause them to swell. Personally I would not run any kind of solvent through the brake system unless I was planning to replace all the rubbers (master cup seals, piston seals, etc).

Silcon-based/mineral brake fluids (DOT5) are immiscible with glycol-based fluids (i.e. DOT 3/4/5.1) or water. That simply means they do not physically mix, but it does not mean they react. If you combine the two fluids and observe for a while, you may notice the purple dye used in DOT5 will eventually mix, but the brake fluid itself will not. Some people have claimed mixing these two fluids will cause gelling to occur. I have not seen actual evidence of this. Some also claim the fluids, when combined, will have some effect on rubbers in the system; I have not seen evidence of that either, but I have very limited experience. Since several aftermarket brake companies advise against it, you may want to be conservative and follow their advice.

I ran DOT 5 silicon fluid in my Nova's original brake system for about 18 years. Back then all I did to switch to DOT5 was flush the system with a lot of DOT5. I wanted silicon fluid because I had painted everything under the hood body color and I was afraid regular DOT3 would end up eating the paint. The DOT5 worked fine for me, but more recently, when changing my master, front lines, and front calipers, I decided to switch back to a glycol based fluid (DOT4). To accomplish this, I used compressed air first to evacuate the rear lines, then I ran/bled a large container of DOT3 (cheaper glycol-based) through the system to flush it, following up again with evacuating the system with compressed air. Then I ran a final flush with DOT4. I did not replace the proportioning valve or rubbers in the rear part of the system. I have not had any issues I could attribute to the fluid; the pedal is firm and the fluid came out clean about a year later when I rebled the brakes. In all likelihood there is probably still some trace residual DOT5 in the system, because it would be nearly impossible to eliminate without using a solvent. However this does not seem to have caused any issues for me.