Brake fluid
 

Can you mix glycol & silicone brake fluid?

Re: Brake fluid
 

No!

Re: Brake fluid
 

No and double no!!! Not only that, the system has to be flushed to switch back and forth.

Re: Brake fluid
 

No. Not compatible at all.

Re: Brake fluid
 

I'm thinking about switching from silicone back to dot 3/4. When you say it needs to be flushed, does it need to be rinsed out with alcohol or something? Or can I just run a lot of the new fluid through the system?

Re: Brake fluid
 

I ran this by Google, it sent me to H.A.M.B. Word there is alcohol flush and air blow, through and out.

Re: Brake fluid
 

Why switch?

Re: Brake fluid
 

I found dot4 to work better than dot3 when testing clutch slave cylinders years ago.

Re: Brake fluid
 

As someone who switched to DOT-5 and then back to DOT-4, I will give you my reasons :

1. Firmer pedal
2. Easier bleeding
3. Relative cost of each
4. My realization that brakes need regular maintenance which includes periodic fluid replacement which negates any advantage DOT-5 may have
5. The fact that no major automobile manufacturer uses DOT-5

Re: Brake fluid
 

I found using speedbleeders and getting good ol' DOT4 when on special [not thats its much anyway] and every two years or so take 15 mins and shes good to go, easy cheap..

Re: Brake fluid
 

I have posted about this before, but nobody seems to listen. You can buy an electronic tester that will tell you the moisture content of DOT-3 and DOT-4 brake fluid. If I remember correctly, anything under 3% moisture is OK. I have been doing this for years now, and it takes about 10-15 years for brake fluid to reach the moisture percentage where replacement is even recommended.

This is for cars that are stored under good conditions; kept inside and not exposed to a lot of bad weather (as most of our cars are). Just think about all of the 20 to 30 years old cars out there with their original brake fluid from the factory. Let's face it; if there was a real danger of brake fluid failing prematurely, there would be all kinds of state and federal regulations mandating regular replacement. I know of none. Flushing the system and replacing the fluid every two years is a complete waste of time and money.

Oh yeah, no matter what I said above, I'm still a real fan of "Speed-Bleeders".

Re: Brake fluid
 

Yes I have one of those and Ive found all cars are different, in fact on my 56 fairlane with a dual circuit system, the rear goes off way before the front, probably less than 2 years Its got me stumped as Ive put all new lines through it. Ive found our more modern cars last way longer than say my 35 pickup even with completely new brake parts..

Re: Brake fluid
 

So. If you are going from Dot 5 to 3 or 4 and flush out the lines with alcohol does it affect the rubber in the master cylinder and wheel cylinders? Or do you not flush the cylinders with alcohol?

Re: Brake fluid
 

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Re: Brake fluid
 

Silicone ( dot 5 ) is Not used in New Cars because most all have ABS.
The very fast pumping action of the Anti Lock actuator causes silicone to foam.
Also, the Cost for car manufacturers to put dot 5 in all the cars they build,
would cost about 4 times more than dot 3.
Plus, they make money selling you new brake parts every few years.


I've used silicone ( dot 5 ) in many of my old cars for many years, and
I would never change back.
I recommend using a mechanical brake light switch with dot 5.
If you spill silicone fluid on your paint, you just wipe it off.
Spill some dot 3 or 4 on your paint and you'll have to dig out your wallet.






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Re: Brake fluid
 

Changing brake fluid type correctly requires disassembly of all cylinders, including the master, and flushing the lines with denatured alcohol. Any contamination of either type of fluid is risky because it is very difficult to switch without the disassembly, given the critical function of the brakes.