Silicone DOT 5 Brake/clutch fluid.

[Misfit]

4 hours ago, RogerH said:

Hi Derek,

as mentioned above when you drain the fluid try and save as much as possible and then leave to stand for 24Hr (sealed)

to see the water content.

 

Roger

Will do 

 

3 hours ago, Z320 said:

Derek,

you had brake fading „currently“ although you use DOT5 since 22 years?

You are our man!

If there is water in the DOT5 sadly it is down on the ground of the calipers and you  only get it out by bolting the calipers off from the axle and turn them upside down.

And you have to be free in your mind to find water and not being convinced not to find water.

The issue is: we all tends NOT to realize what will disappoint us (cognitive dissonance reduction) or what we have been convicted for a long time.

Ciao, Marco 

 

Its not unusual but  perhaps I didn’t explain I was on dot 4 in 2000 when I had brake fade and changed on return to the UK to Dot 5. 

I haven’t changed the dot 5 fluid since. I will now together with my flexi pipes and steel brake pipes to a copper mix. Discs, callipers   and drums appear fine,  but I will change the brake cylinders. 
 

I’ll do that Roger after 22 years it will be interesting to see how much water is in it.

Thanks Derek 

 

[stillp]

Here's an interesting comparison site: https://penriteoil.com.au/knowledge-centre/Types of Brake Fluids/107/silicone-brake-fluid/307

The lower lubricity of DOT 5 is something I didn't know, although I can't see that being a problem in a car that doesn't have ABS.

I had to remove a caliper a couple of years ago, and took the opportunity to drain as much brake fluid as I could. I couldn't see any water in the fluid at all, but I only left it stand for a couple of hours so perhaps that wasn't long enough for the water to settle out.

Pete

[stuart]

10 minutes ago, stillp said:

Here's an interesting comparison site: https://penriteoil.com.au/knowledge-centre/Types of Brake Fluids/107/silicone-brake-fluid/307

The lower lubricity of DOT 5 is something I didn't know, although I can't see that being a problem in a car that doesn't have ABS.

I had to remove a caliper a couple of years ago, and took the opportunity to drain as much brake fluid as I could. I couldn't see any water in the fluid at all, but I only left it stand for a couple of hours so perhaps that wasn't long enough for the water to settle out.

Pete

Their comparison tables are based on DOT3 fluids which are more suited to drum brake applications as opposed to the DOT4 or DOT5.1 that most of use use.

Stuart.

[Andy Moltu]

On 9/12/2022 at 3:09 PM, Z320 said:

What advice is this?

The moment you get steam to bleed out (if this will ever be the case)

you hopefully will not die by a car accident because of a brake failure.

Please everybody: don’t do that.

I am talking about the tiny amount of water vapour that has condensed in the master cylinder and made its way to the calipers on otherwise perfectly functioning brakes to deal with the possibility of it becoming  a problem in the future. Once you get the fluid in the caliper to 100+ Celsius the water will vaporise once depresurised.

Bleeding hot brakes is no more or less dangerous to other road users than Dot4.

On a modern abs fitted car we change the brake fluid every 2 or 3 years because of water contamination. Regular brake fluid is hygroscopic and will absorb water from the atmosphere. DOT5 doesn't so it's just condensation that enters the system and as water and DOT 5 are imiscible the water will sink to the lowest points.

 

[Tim D.]

This is really a discussion that is hard to resolve without real data.  Which is why it re-erupts. What I interesting is both fluids are legal, even in the litigation rich environment of the states. So both are deemed safe. So it us really consumer choice. 

As I say I run both. 

But I will definitely empty a caliper for the team this winter. With no prejudice. :-).

Cheers

Tim

[PaulAnderson]

I have silicone fluid in both my brakes and clutch systems and have done so since the car was rebuilt over 20 years ago.   I’ve had a recent leak from the clutch master cylinder which I’m about to swop out.   I’ll be flushing out the system and my question is, how do you dispose of old silicone fluid.  I recall seeing waste oil collection at my local council recycling but don’t recall seeing any signs for fluid such as this

Paul

[Z320]

At Germany: return the old fluid to the shop that sold you the new one.

[Tim D.]

I would go to your local recycling centre. According to the meterial hazard sheet it is not considered environmentally hazardous and in theory you can incinerate it if it is only a small amount and it just degrades to silicon oxide.

Tim