Silicone Brake Fluid Experiment

[JHZR2]

Ive talked for a while about the possibility of using synthetic brake fluid as an option for rubber seals and other parts. Something like AGS DOT 5 brake fluid is primarily Dow Corning silicone oil with a tiny bit of a phosphate additive (MSDS available online and linked to in other threads).

I didnt do door seals yet, but I can report back on another rubber part - a rear subframe bushing. One of mine on my 91 318i (168k miles) creaked a bit at launch. I decided to apply the silicone brake fluid to that bushing to see how if would work. Im happy to say that it has kept it quiet! Im happy. No indication of paint issues where the stuff contacted either.

The fluid is purple, and much less viscous than I expected. I just put it in a spray bottle, and while I cant get it to atomize, it squirts well.

 

[spasm3]

I would not have thought of using dot 5 brake fluid, thats pretty ingenious! I think i can read on the bottle that its compatible with neoprene and natural rubber. I might have to try this on seals of the avalanche truck bed covers!

 

[JHZR2]

Originally Posted By: spasm3
I would not have thought of using dot 5 brake fluid, thats pretty ingenious! I think i can read on the bottle that its compatible with neoprene and natural rubber. I might have to try this on seals of the avalanche truck bed covers!



And it also claims compatible with paint, which was a concern with the very minority additive component...

But that may just be transient interface and not continuous contact. Still, Ive not seen any effect.

 

[nitehawk55]

Won't hurt your paint , I've been using it on my door rubbers for years so the doors don't freeze closed in the winter . Bottle lasts for years !

 

[antiqueshell]

Smart man. Good find!

 

[expat]

I have used it as a lube to press in new suspension bushings.
It worked really well.
I was going to use Dish washing liquid, but was told that it might contain salt.

 

[GMorg]

Like nitehawk55, I have used DOT5 around door seals for several years. It also works well to to put a nice shine on plastic bumpers. However, in areas that are directly exposed to rain, it washes off amazingly fast. Keep in mind that Armor All is a water/silica oil emulsion. A few squirts of Armor All may be just as good.

 

[buck91]

Good to hear, JHZR2