brake fluid identification - help please

[BlurE]

Hi all, I need to bleed my Marc Ingegno brake system and would like to top up the fluid as required.

 

Maintenance manual does not specify a fluid grade. Looking at it, it appears completely colourless and looks as clear as water in the nylon lines. 

 

Does anyone have any idea what this might be or how I can test it? I know a number of fluids are not compatible.

 

Cheers

 

 

 

[Jaba-who]

Do a google search etc or call the company. 

 

As as far as I am aware brake fluids can be all colours.   Ive used a number of brands that have been green, clear or red and they are the same stuff

 

 

[spenaroo]

I have zero experience with aircraft brakes.

 

but it is usually written on the reservoir cap.

 

 

[skippydiesel]

Hi BlurE -

 

Be careful, aircraft brakes can use radically differing types of fluid.

 

Brake components, particularly the "rubber"/flexible seals etc may not be compatible with certain brake fluids.  The wrong fluid may cause accelerated ageing/perishing and softening resulting in a brake failure.

 

The introduction of the wrong fluid, either in topping up or replacing, may react badly with the old fluid causing blockages, shortened service life, etc etc

 

My aircraft uses ordinary Dot 4 automotive fluid BUT do not assume yours will be the same.

 

As Jaba-who said automotive brake fluids can be almost any colour - green, dark/light blue, yellow, almost colourless (straw) etc etc. The colour is  a branding/sales gimmick, although in some cases changes in colour ,while in service, may indicate when the fluid should be changed.

 

One other point - standard automotive brake fluids should be changed at no more than 2 year intervals due in large part to their hydroscopic characteristics the result of which which will reduce brake efficiency , corrode internal brake components, etc.

 

 

[kgwilson]

Automotive brake fluids will not function well if at all at high altitudes. Mil spec fluids are petroleum based and usually red.

 

 

[Downunder]

Doing a bit of research, it seems the brake mfg makes brakes for both hydraulic and "dot 4" fluids.

 

Best contact aircraft mfg.....

 

As everyone has said.....don't get it wrong!

 

 

[Thruster88]

Does it smell, feel like brake fluid or smell feel like hydraulic oil, if it is oil like most VH aircraft it won't mix with water.

 

 

[Jaba-who]

Automotive brake fluids will not function well if at all at high altitudes. Mil spec fluids are petroleum based and usually red.

But non-mil spec stuff of different types can be red as well. Unless you know what it is it would be very unwise to take any notice of colour. 

 

 

[Downunder]

If it is hydraulic, this is what you need.

 

https://www.ebay.com.au/itm/Phillips-66-Aviation-Hydraulic-oil-Cessna-Piper-Aircraft-Engine-RV-Lycoming-/232810261222

 

Needs to be milspec 5606.....

 

 

[BlurE]

Thank you for the advice everyone. I'll do some more investigation. 

 

 

[skippydiesel]

Automotive brake fluids will not function well if at all at high altitudes. Mil spec fluids are petroleum based and usually red.

Often heard this observation - just wondering how high ? AND how often are you are using your brakes at high altitude?

 

I suspect the "problem" with common automotive brake fluid is its propensity to attract moisture (hydroscopic). The moisture may the freeze at very low temps - damaging components, "flash" heat to steam - reducing brake efficacy, etc etc.  

 

Its probably wrong to lump fluids into automotive and aviation - I believe there is a Rolls Royce brake fluid which is basically a hydraulic oil and also a very expensive a silicon brake fluid which never needs to be replaced (except when leakage occurs).

 

Further most of the "issues" will be around component comparability with the brake fluid and failure to replace the fluid at the manufactures recommended service intervals.

 

 

[David2ayo]

Sometimes I think bowden cables or rods are more reliable - what you see is what you get. Automotive fluid Dot5 is the silicon version, as used in some American military vehicles and Harley Davidson motorbicycles. For some reason, probably hatched after a heavy night at a local alehouse, Dot 5.1 is back to a 'normal' glycol based fluid. I suppose one test is to put some on a painted surface - silicon fluid doesn't harm it, glycol will.

 

Once you've figured out what you should use, then put labels EVERYWHERE to indicate what it should be!

 

 

[skippydiesel]

Sometimes I think bowden cables or rods are more reliable - what you see is what you get. Automotive fluid Dot5 is the silicon version, as used in some American military vehicles and Harley Davidson motorbicycles. For some reason, probably hatched after a heavy night at a local alehouse, Dot 5.1 is back to a 'normal' glycol based fluid. I suppose one test is to put some on a painted surface - silicon fluid doesn't harm it, glycol will.

Once you've figured out what you should use, then put labels EVERYWHERE to indicate what it should be!

You could go one step further - dismantle one of your slave cylinders/caliper - put the "rubber" components in DOT 4 (glycol based) - if they soften and or swell its the wrong fluid - eliminated the most common automotive brake fluid.

 

With the other slave cylinder/caliper components, try a mineral oil brake fluid (some of the  aviation types & RR) - if you still get softening/swelling the third type silicon based brake fluid must be what you are after.

 

One other alternative is to replace all your "rubber" bits (including lines) with known resistant to ?? components and then use  ?? brake fluid from then on & NOTE it in your maintenance log..

 

 

[fly_tornado]

my brakes specify Automatic transmission fluid

 

 

[skippydiesel]

my brakes specify Automatic transmission fluid

Well there you go - however automatic transmission fluid (& power steering fluid) are likely to be a mineral oil. One other thing  - automatic transmission fluid comes in different types ie just saying auto fluid is not enough  info - which one?

 

 

[M61A1]

Well there you go - however automatic transmission fluid (& power steering fluid) are likely to be a mineral oil. One other thing  - automatic transmission fluid comes in different types ie just saying auto fluid is not enough  info - which one?

I think "mineral" is what they are looking for. Most the MIL-H-5606 (not skydrol) is mineral compatible even though there are synthetic versions of it. The Automotive brake fluids generally are not compatible and will destroy your seals, wreck your paint and other stuff. Almost any mineral oil will do. The red stuff is good because its easy to see in transparent lines and identify if it's leaking.

 

 

[Yenn]

GA aircraft use 5606 usually and this is a petroleum based fluid, usually red in colour. They can also use automatic transmission fluid, which has the advantage that it does not have as great a tendency to leak. You really need to talk to the manufacturer of your plane.