The Stovebolt Site Forums The Shop Area Driveline Wheel cylinder lube

Changing the rear wheel cylinders ( Huck brakes) on my 49 3100. Continuing to use Dot 5 fluid. Should I use brake fluid to lube the rubbers and cylinder wall or is there a better alternative? Thanks Ed

Not one I've ever found.

Brake fluid is the only recommended lube.

They are correct, unless you use a product specifically made for that purpose.

Thanks for the input. I'll stick with brake fluid.

The nice thing about brake fluid, except for DOT 5 which exhibits more compressibility, is that it absorbs moisture. So the brake fluid left exposed after using it as an assembly lube will start causing corrosion right away. Like between the cup and the boot. Which eventually damages the steel, then the cup and causes leaks. Then wheel cylinder failure.

I agree with Mark, I only use "Brake Assembly Lube" and do my best to keep the DOT-3 OFF of everything else because it eats paint and starts premature corrosion.

Mike B

I'll continue to use Dot 5 in my system, don't think there will be issues like Dot 3/4.

You'll be fine with DOT 5.

Some old timey service documents make reference to using mineral oil to lubricate brake parts at assembly with implication that it was the method used by GM factory.
-s

The 47-53 service manual has a note on brake cylinder disassembly that says "Do not use gasoline, kerosene, or any other cleaning fluid that might contain even a trace of mineral oil." which implies that mineral oil is not good.
It also says to "dip internal parts in brake fluid" on assembly.

Ah then they must of changed their mind on mineral oil
Perhaps there was an incident
If I find the document that said to use it I’ll try to remember to post it for interest sake
But by all means done use that stuff then!
Thanks
-s

Some brake fluid is still made of mineral oil, for what it is worth. Most today are ether/glycol (except for DOT5 which I think is silicone based), but LHM stands for Liquide Hydraulique Mineral. What I've seen is green and it won't absorb water.

I use a thin film of silicone grease. It may not desolve in the brake fluid but a small amount will never hurt anything. It is really slick.
George